Laura Puchot

Etienne Fleury

Florent Allais

Valérie Langlois

Frédéric Vidal

Youssef Habibi

Recently, considerable interest of the chemistry of renewable ressources and their resulting materials has grown with a view to reduce the use of finite petroleum-based resources. The present thesis entitled « Cardanol: a bio-based building block for new sustainable and functional materials » is dealing with the chemical modification of cardanol and its use for various applications. Cardanol is a naturally occurring phenolic compound issued from cashew nutshell liquid. Its chemical structure is interesting because cardanol is bearing a phenolic hydroxyl function and an unsaturated alkyl chain in meta. Numerous chemical reactions can thus be considered for its chemical modification.

The first part of this study is dealing with the synthesis and the characterization of three cardanolbased ammonium surfactants differing by their amine functionalities content. Their effectiveness on the exfoliation of silicate clay within an epoxy matrix was investigated with the aim to elaborate composite materials.

The second chapter is describing a novel method for the synthesis of bio-based benzoxazine monomers and the elaboration of polybenzoxazine networks issued from cardanol. A new generation of benzoxazine monomers issued from cardanol or from lignin derivatives such as vanillin were recently developed. However, up to now, the majority of the synthetised benzoxazine monomers are mainly mono-functionnal or display too high melting temperatures.

The elaboration of valuable self-standing materials is thus strongly impeded. To solve this problem, an innovative synthesis of asymmetric benzoxazine monomers by combination of cardanol and lignin derivatives is described. The resulting self-standing materials display improved properties in comparison to materials issued from symmetric bio-based monomers.

Finally, the third chapter realtes to the use of a cardanol-based epoxy pre-polymer for the elaboration of bio-based epoxy materials. Nevertheless, this new material displays low Tg due to the alkyl side chain of cardanol in addition to low water uptake. In order to reinforce the thermomechanical properties of the material and to reduce its water uptake, a chemical modification was achieved at the macromolecular scale by the elaboration of interpenetrating polymer networks with polybenzoxazine networks.

These various studies allowed to highlight the easy and versatile modification of cardanol, resulting thus in a diversity of bio-based synthons and their resulting materials. This work paves the way to the elaboration of other chemical structures and molecular architectures for various applications.

Résumé:

Récemment, la chimie des ressources renouvelables et les matériaux qui en découlent ont suscités un intérêt considérable dans le but de limiter l'utilisation des ressources fossiles. La présente thèse intitulée « Cardanol : a bio-based building block for new sustainable and functional materials » traite de la modification chimique du cardanol et de son utilisation dans diverses applications. Le cardanol est un dérivé phénolique naturel extrait de l'huile de coque de noix de cajou. Sa structure chimique est intéressante : il est substitué d'une chaîne alkyle en C15, partiellement insaturée, et il est porteur d'une fonction phénol, permettant d'envisager de nombreuses réactions chimiques.

La première partie de cette étude traite de la synthèse et de la caractérisation de trois surfactants ammoniums issus du cardanol se différenciant par le degré de substitution de leurs amines. Leur capacité à favoriser l'exfoliation d'une argile lamellaire dans une matrice de type époxy a été étudiée dans le but de concevoir des matériaux composites.

Le second chapitre décrit une nouvelle méthode de synthèse de monomères benzoxazines biobasés et l'élaboration de réseaux polybenzoxazines à partir du cardanol. Une nouvelle génération de monomères benzoxazine, issus du cardanol ou de dérivés de la lignine tels que la vanilline, a récemment été développée. Cependant l'essentiel des benzoxazines bio-basées synthétisées jusqu'à présent sont monofonctionnelles ou présentent des températures de fusion trop élevées.

Elles ne permettent donc pas l'élaboration de matériaux autosupportés valorisables. Afin de pallier ce problème, une synthèse originale de monomères benzoxazines asymétriques, reposant sur la combinaison de cardanol et de dérivés de la lignine, est décrite. Les matériaux autosupportés résultants présentent des propriétés améliorées par rapport à celles que ne pourraient atteindre les monomères symétriques issus de ces phénols bio-sourcés.

Finalement, le troisième chapitre concerne l'utilisation d'un pré-polymère époxy issu du cardanol pour l'élaboration de matériaux époxy bio-basés. Cependant, ce nouveau matériau présente une faible Tg en raison de la chaîne alkyle du cardanol et une faible prise en eau. Afin de renforcer ses propriétés thermo-mécaniques et de diminuer sa prise en eau, une modification chimique a été réalisée à l'échelle macromoléculaire par l'élaboration de réseaux interpénétrés de polymères à base de réseaux polybenzoxazines.

Ces différents travaux ont permis de mettre en avant la modification aisée et versatile du cardanol, pouvant ainsi résulter en une large variété de synthons bio-basés et des matériaux qui en découlent. Ces travaux ouvrent la voie vers d'autres structures et architectures moléculaires aux applications nombreuses.

FTIR

Fourier Transform Infrared Spectroscopy

HAD Hexamethylenediamine

HRMS

List of Tables

General Introduction and Context

In the recent years, the interest of the researchers, both from the academy and industry, in the chemistry of renewable resources and related materials has considerably grown. Indeed, until recently, the largest part of the resources used for the production of commodity materials is mainly petroleum-based compounds. Furthermore, the world production of plastic materials is constantly increasing, reaching in 2014 a production of 311 million tons of plastic, using 8 % of the global petroleum annual world production. 1 The production of petroleum-based plastic materials concerns a wide range of applications such as packaging (39.5 %), building and construction (20.1 %), automotive (8.6 %), electrical and electronics (5.7 %) or agriculture (3-4 %). Various sectors such as consumer and household appliances, furnitures, sports, or health and safety constitute 22.7 % of the global demand. However, the depletion of fossil resources, combined to their increasing prices and the growing environmental concerns, led to huge demand in the development of new bio-based precursors. Nowadays, bioplastics are representing a minority of the world plastic production, less than 1 % of the global plastic production. 2 In 2013 the bioplastic production amounted only around 1.6 million tons. Nevertheless, the demand is rising, and by 2018 the production capacity is expected to increase to 6.7 million tons, leading to more and more sophisticated bioplastic materials (Figure 1). In consequence, numerous researchers focused in the past few years on the use of naturally occurring building-blocks for the synthesis of monomers and polymeric materials. Up to now, the natural resources used to this aim are predominantly agricultural crops such as corn, cereals, sugar beets and sugar cane (first generation feedstock); most of them competing with food value chain. Nevertheless, the bioplastic industry favours now the natural resources provenance rather towards non-food crops and non-edible by products (second and third generation feedstock), among others, cellulose. Indeed, a large amount of cellulosic by-products are produced by the growing of crops such as straw, corn stover or bagasse which could be recovered. Other renewable materials such as wood, proteins, lignin, tannins, starch, vegetables oils or even animal resources such as chitin, are also widely studied and used. However, many of these naturally occurring resources exhibit important drawbacks such as low purity and high molar masses, reducing their industrial development. The depolymerisation of lignin for example also remains very challenging, limiting its exploitation as source of chemical building blocks. 3 Among the possible raw renewable materials available for the development of new bio-based materials, cardanol is gaining considerable interest as a natural source of phenol and a versatile building block. 4 Cardanol is produced from Cashew Nutshell Liquid (CNSL), and is an economical and abundant non-edible agricultural annually renewable resource used in many applications in research and industry. 5 Indeed, in 2013, the world production of cashew nuts in shell was estimated to 4.4 million tons. 6 Beside the sustainability, availlabatility and the advantageous price of raw cardanol compound, its particular aromatic structure makes it an interesting and promising natural alternative to petrochemical derived phenols. Indeed, due to similar reactivity to a phenol compound and through various chemical modifications on its three main availlable reactive sites, a wide range of molecules can be designed with wide application range such as surfactants, plasticizers or polymer precursors. The raw cardanol compound was already intesively studied, and a state of the art of the possible chemical modifications and their applications will be described in a first introductive chapter. The following chapters are them highlighting various chemical modification strategies we applied to cardanol for the elaboration, or the reinforcement of polymeric materials as tentative ways to find new high value applications of these raw biobased building blocks.

First of all, we report in Chapter II the synthesis of a set of novel cationic surfactants prepared from cardanol. The synthetized ammonium cardanol-based surfactants exhibited interesting properties. They were thus herein applied for the organomodification of Montmorillonite (MMT), a clay mineral widely used as filler in polymer materials for its reinforcing, thermal and gas barrier properties. Indeed, it is well established that the chemical structure of surfactants used for the organomodification of clay minerals plays an important role on the clay exfoliation during the elaboration of nanocomposite materials. The compatibilization of clay mineral and polymer material may be enhanced by the incorporation of reactive surfactants capable to covalently graft to monomers and polymer chains. It will be evidenced that cardanol-based surfactants act as efficient compatibilizers of MMT within epoxy polymer. Furthermore, it will be demonstrated that the reactivity of the synthetized surfactants plays a particular role on the clay exfoliation mechanism within an epoxy matrix. Interestingly, different (nano)composite structures were observed depending on the reactivity of the surfactants.

As highlighted before, cardanol is a naturally occurring phenolic compound that has recently attracted attention for the synthesis of benzoxazine monomers. Undergoing the efforts to promote the development of bio-based benzoxazine thermosets, we explore in Chapter III a new strategy for the elaboration of bio-based and processable Bz-materials. In particular, Bz monomers from cardanol alone or in conjunction with some lignin derivatives -like vanillinwere studied. A versatile synthesis of asymmetric di-benzoxazine monomers from naturally occurring phenolic compounds cardanol and vanillin was developed. By taking advantage of the low reactivity of cardanol, a mono-substituted cardanol-based benzoxazine monomer was prepared and further coupled with vanillin to yield vanillin-cardanol di-benzoxazines. The asymmetric monomer presents the great advantage of displaying a low melting temperature and thus a wide processing window, facilitating its processing (melting and shaping). Furthermore, a moderate gelation time was observed as well as high Tg for the polymerized material. Such strategy constitutes an efficient and versatile route for an easy elaboration of bio-based monocomponent thermosets.

Finally, in the last chapter we envision the substitution of Bisphenol A -a well-known endocrine disruptor -in coatings, by using diglycidyl ether of cardanol (CDGE). Because of its weak properties (Tg, storage modulus, water repellence), coatings prepared with CDGE need to be reinforced. In particular, we focused on a macromolecular reinforcement by the elaboration of interpenetrating polymer networks of CDGE and polybenzoxazine (PBz). Indeed, CDGE thermoset materials display poor thermo-mechanical properties, whereas PBz resins are well-known for being high performance materials. In spite of the possible co-crosslinking between cardanol diglycidyl ether and benzoxazine monomers, leading to polymer co-networks, we found the appropriated experimental conditions to only tangle the two polymer networks without chemical links between the two networks. The elaboration and the properties of these interpenetrating polymer networks are reported in this last chapter.

Chapter I: Introduction were also found to be present mainly in technical CNSL. The industrial grade of cardanol oil recovered from CNSL, may reach 90% of cardanol content and a smaller percentage of cardol and methylcardol. 12,13 As above mentioned, cardanol is a mixture of four phenolic molecules differing by their degree of unsaturation of their alkyl side chain and the determination of their relative abundance has been the subject of many researches through various methods. The reactive hydroxyl group on cardanol allows chemical reactions such as esterification, 14 allylation, 15,16 epoxidation, [17][18][19][20][21][22][23][24][25] or ethoxylation. 26,27 Structural changes may also occurred by reacting the aromatic ring, for example through condensation, 28 nitration, 29 sulfonation, 30,31 bromination, [START_REF] Attanasi | Organic preparations and procedures international[END_REF] and hydrogenation. [START_REF] Madhusudhan | Industrial & Engineering Chemistry Process Design and Development[END_REF] Furthermore, cardanol can also undergo chemical modifications on the C15 alkyl side chain. Indeed, the side chain unsaturations enable reactions such as hydrogenation, [START_REF] Madhusudhan | Industrial & Engineering Chemistry Process Design and Development[END_REF] hydrosilylation, 34 epoxidation, 17,18 phenolation, 35 or metathesis reactions. 36 Consequently, cardanol is used in a wide range of applications (plasticizers, surfactants, curing agents, antioxidants), depending on its chemical modification, as described in the following sub- 3 Cardanol based chemicals and functional molecules Among fine chemicals and functional molecules from cardanol reported in the literature, there are plasticizers, surfactants, curing agents or antioxidants.

Plasticizers and reactive diluents

The incorporation of a plasticizer molecule within a polymeric material increases its flexibility Hence, with the actual concern of replacing the commonly used phthalate-based plasticizers because of toxic release, 37 both raw and chemically modified cardanol compounds are intensively used as plasticizer.

For instance neat cardanol has been used as plasticizer for Poly(methyl methacrylate) (PMMA) as reported by Prabhakaran et al. 38 . The rheological properties were influenced by the addition of cardanol to PMMA. The viscosity decreased from 6.4 Pa.s to 1.5 Pa.s with increasing the weight ratio of cardanol/PMMA from 0.33 to 1. Furthermore, the plasticizing effect of cardanol was evidenced by the decrease of the Tg of PMMA-cardanol blends from 48 °C to -12 °C with the addition of 50 wt % of cardanol in PMMA.

Chlorinated cardanol as well as its chlorinated acetyl and methoxy derivatives were tested for the partial replacement of dioctyl phthalate (DOP) in polyvinyl chloride (PVC) leading to an improvement of the properties of the material as resumed in Table I -3. 39 The DOP was added to the PVC compound in a 50/50 ratio to the synthetized cardanol-based plasticizers. The chlorinated cardanol methyl ether (Cl-cardanol methyl ether) appears to be a good plasticizer for PVC with comparable performances to DOP, particularly thermal once. Similarly, acetyl cardanol derivatives were evaluated as plasticizer in PVC. 14,40,41 Thermal and mechanical properties of the resulting PVC-based materials were comparable to those of PVC plasticized with di-ethyl-hexyl-phtalate (DEHP) or DOP lonely.

Plasticizer

However, a well-known drawback of plasticizers is their migration from the bulk to the surface of the host polymer matrix. To prevent this phenomenon plasticizers are generally modified with a reactive function towards the polymer matrix (reactive plasticizer). Furthermore, the addition of a reactive plasticizer to high viscosity epoxy is known to reduce the viscosity and facilitate the materials processing. In the case of cardanol, the most common reactive cardanol-based plasticizer used to prevent its migration is obtained from the reaction of cardanol with epichloridrin in basic conditions. This cardanol derivative is commercially available under the

Surfactants

Surfactants are amphiphilic molecules constituted of a hydrophobic part (the tail) and a hydrophilic group (the head). They are largely used as detergents, wetting and/or foaming agents, emulsifiers or dispersants due to their ability to lower the surface tension of a liquid, between two liquids or between a liquid and a solid. [START_REF] Yang | Mechanical Engineering, Materials and Energy III[END_REF] Petroleum-stemmed linear alkyl benzenes are the most commonly used reactants for the synthesis of surfactants. A sustainable alternative would be the synthesis of cardanol-based surfactants as it could be expected from its appropriate chemical structure. Even though unmodified cardanol cannot be considered as surfactant but its chemical structure and inherent amphiphilic properties are ideal for the synthesis of bio-based surfactants. Indeed the C15 alkyl chain represents the hydrophobic part while the aromatic ring bearing a hydroxyl group represents the slightly hydrophilic part. The amphiphilic properties of cardanol can be accentuated by chemical modifications of the phenolic hydroxyl group, obtaining thus cardanol-based surfactants. Through numerous possible chemical modifications of its phenolic hydroxyl function, various types of surfactants were synthetized from cardanol such as anionic, non-ionic or cationic surfactants. Surfactants may also bear reactive functions and could thus be able to take part in polymerization reactions. These reactive-surfactants known as "surfmers" can be used in order to improve the final material properties. 46 The CMC of the reactive surfactants were reported to be much lower than the conventional SDS

Cationic surfactants

Cationic surfactants can also be synthetized from cardanol. Nevertheless only two studies are reported in the literature. The synthesis of a quaternary ammonium salt from cardanol was described. 49 The distinctive feature of this compound is the quaternary ammonium located at the Several heterogeneous reactions such as oxidations and Williamson ether synthesis were tested with cardanol quaternary ammonium salt as phase transfer catalyst. The synthesis yields were reported similar or even higher to those obtained with a commercially available quaternary ammonium salt (Aliquat ® ) (Table I The Tg values obtained using DSC increased in the order ARK351 < PA1 < PA2 < PA3. An increasing of the crosslinking density and of the Tg of the thermosets was reported to be in relation with the increase of the phenalkamine molecular weight and amine content. In addition, it is assumed that the cycloaliphatic moiety in cardanol-based phenalkamines samples was also responsible for higher Tg than ARK351 sample, which was based on aliphatic polyamine. Nevertheless, the high toxicity of formaldehyde, identified as a carcinogenic compound, in addition to low primary amine functionality of the resulting phenalkamines are main drawbacks for the use of Mannich-based phenalkamine curing agents. To overcome these shortcomings Darroman et al. 16 proposed the synthesis of a cardanol-based aromatic amine

Properties

Antioxidant

Antioxidants are used as additives in various polymer-based materials. Indeed, their presence inhibits the deterioration of the organic material by oxidation under atmospheric conditions which increases the material lifetime. The most current and efficient additives are ortho and/or para substituted phenolic compounds. The anti-oxidant effect is depending on the substituents electronic effects and on their steric hindrance. Indeed, electron-donating effect of the substituents increases the hydroxyl oxygen electron density, resulting in an efficient radical trap.

An important steric hindrance of the substituents prevents the coupling of phenoxy radicals and increases their efficiency. 57 Cardanol, through its phenolic chemical structure and particularly through the steric hindrance brought by the alkyl side chain has been reported to be a suitable compound for antioxidant applications, especially for petroleum products. Nevertheless, the antioxidant activity of nonmodified hydrogenated cardanol and cardol compounds was very low in comparison to commercial antioxidant compounds such as butyl hydroxyl toluene (BTH). 58 In consequence, various modifications of cardanol were reported (Figure I -25) attesting of its efficiency as radical scavenger.

The alkylphenol synthetized by Rios et al. 59 The presence of the alkyl side chain increases hydrophobicity and results in highly flexible materials with lower mechanical properties than usual phenol-formaldehyde resins. As a consequence, cardanol-formaldehyde resins are barely used alone, but mainly in blends with phenol-formaldehyde resins to obtain materials with good toughness. 28,64,65 Some studies also reported the substitution of formaldehyde by furfural -a bio-based heterocyclic aldehyde obtained from agricultural waste -and the synthesis of cardanol-furfural resins (Figure

I -27).

The replacement of formaldehyde by furfural promotes the thermal stability of the phenolic resin. Indeed, according to the TGA results, cardanol-furfural resins display a higher thermal stability as cardanol-formaldehyde resins. The furfural moiety of cardanol-furfural resins was shown to be thermally more stable than the methylene bridge of cardanol-formaldehyde resins. 66 Cardanol is a good precursor for the synthesis of polyurethane resins considering its easy conversion to polyol compound. The most current modification to obtain polyols from cardanol relies on the reaction of the cardanol hydroxyl group or by condensation on the phenolic ring.

Furthermore, previous researchers reported the use of cardanol derivatives for the elaboration of PU materials with enhanced thermal and mechanical properties. PU resins exhibiting good thermal and mechanical properties were obtained for example from pre-synthetized cardanolformaldehyde resins, [67][68][69][70] or from cardanol-furfural resins. 71 Nevertheless, direct synthesis of cardanol-based diols or polyols was also considered for the elaboration of cardanol-based PU materials. These syntheses are detailed in the following paragraphs.

Synthesis of cardanol-based polyols

Cardanol-based diols (Figure I -29) have been synthetized by reaction of cardanol hydroxyl group with 3-chloropropane-1,2-diol, 72 with epichlorohydrin, 73 or by condensation of paminophenol on cardanol. 69 The two first syntheses resulted in the formation of aliphatic diols while the third approach aimed at forming a molecule bearing two phenol moieties. I -10). The lower Tg of PU material from CAP2 compared to PU material from CAP1 is probably due to the long carbon chain introduced on the phenolic hydroxyl group and increasing the flexibility of the polymer chains. The degradation temperatures showed no remarkable difference because the degradation process is mainly attributed to the cardanol chain scission. wt% weight loss and Tmax is the temperature at maximum rate weight loss).

Sample

Cardanol-based non-isocyanate PU

The handling of isocyanate raw materials and their use for the production of polyurethane products has become an issue due to the high toxicity of isocyanate. In this context, the development of non-isocyanate polyurethanes through the reaction of amines and cyclic carbonates is of growing interest. The synthesis of cashew nutshell liquid (CNSL)-based urethane polyols via a non-isocyanate route has been reported. 78 Cyclic carbonate derivative of diglycidyl ether of cardanol was obtained by addition reaction of high pressure CO2 followed by reaction with primary hydroxylamines yielding to the formation of hydroxyl and urethane groups (Figure

I -35).

The so-synthetized polyols were then cured using hexametoxy methylene melamine as hardener yielding PU materials. Finally, an enzymatic synthesis was proposed as a green approach for the epoxidation of Cardanol (Figure I -39). [START_REF] Kim | [END_REF] The unsaturations of the alkyl chain were epoxidized by reacting with lipase in the presence of acetic acid and hydrogen peroxide, prior to form a polymer with epoxyfunctionalized pending C15 chains through coupling of the phenol moieties with peroxidase and hydrogen peroxide. Peroxidase was shown by the authors to polymerize meta-substituted phenols such as cardanol with chemical selectivity. Peroxidase was thus used to obtain polycardanol and epoxide-containing cardanol. During the epoxidation by lipase/H2O2/acetic acid, some polycardanols are crosslinked due to highly oxidative environment. The amount of crosslinked polycardanols is higher for the polymer (Route B) than for the monomer (Route A).

The route A rather the route B is thus recommended to produce epoxide-containing polycardanols as prepolymer. Finally the as-synthetized prepolymers were cured with a phenalkamine to elaborate the final crosslinked material. Film samples of 50 µm thickness were prepared on a glass slide. The hardness of the resulting materials measured by pencil scratch technique revealed that the hardness improved with increasing epoxy content suggesting that the epoxy groups play a major role in the materials hardness. Epoxide-containing polycardanols reached the highest hardness of 9 H when cured for 5 h at 150 °C, a higher value compared to a commercially available alkyl resin coating at 4 H. Furthermore, the addition of a phenalkamine curing agent still enhanced the hardness to the material up to 5 H within 2 h curing. Epoxide containing polycardanol resins were thus demonstrated to be a viable bio-based alternative to phenol-formaldehyde resins for applications requiring high hardness and mechanical durability.

Conclusion

This first chapter highlights that cardanol is an important industrial crop that can be used for many applications. Furthermore, the presence of different reactive sites (phenol, unsaturation etc.) makes it as versatile chemical platform to design a wide range of molecules with high addedvalue applications such as surfactants, antioxidants or plasticizers to polymer precursors. In particular, due to its intrinsic properties, cardanol has been widely used for the synthesis of biobased surfactants and for the elaboration of phenolic, epoxy, or polyurethane materials. More recently, the use of cardanol for the design of benzoxazine monomers is gaining more and more interest, since it tackles several issues frequently encountered with benzoxazine monomers such as high melting temperatures or the high brittleness of the resulting polybenzoxazine materials.

The following chapters are highlighting various chemical modification strategies we designed to access new cardanol-based derivatives to be used for the elaboration or reinforcement of polymeric materials.

The chapter II deals with the synthesis of reactive ammonium cardanol-based surfactants and the study of their reactivity for the preparation of clay composite materials with BADGE. In the chapter III a new strategy for the elaboration of bio-based and processable Bz materials by combining cardanol with other naturally occurring phenolics is reported and studied. Finally the use of Bz resins for the macromolecular reinforcement of a cardanol di-glycidyl ether resin by the elaboration of interpenetrating polymer networks will be investigated.

Chapter II: Surfactants from cardanol

1 Introduction
Due to its naturally amphiphilic structure, cardanol is an excellent candidate for the preparation of surfactants, as it has been detailed in Chapter I -3.2. Indeed, surfactants are amphiphilic molecules constituted of a hydrophobic part (the tail) and a hydrophilic group (the head). The C15 alkyl side chain provides an essential hydrophobicity while the slightly polar hydroxyl group allows a wide variety of chemical functionalization. 82 Notwithstanding this particularly adequate structure, cardanol-based surfactants are just emerging as a green alternative to conventional petroleum-derived nonylphenols for the preparation of surfactants. 4,30,31,[START_REF] Anilkumar | [END_REF][45][46][47][48][49]51 Surfactants are largely used as detergents, wetting and/or foaming agents, emulsifiers or dispersants due to their ability to lower the surface tension of a liquid, between two liquids or between a liquid and a solid.

They are also largely used as clay organomodifier for the elaboration of clay-polymer nanocomposite materials. In the present chapter, we aimed at synthesizing new ammonium cationic surfactants from cardanol displaying different reactivities. Then we studied their effect on the exfoliation of Montmorillonite clay within Bisphenol A diglycidyl ether (BADGE) epoxy thermoset for the elaboration of composite materials. A state-of-the-art about the elaboration of silicate layered polymer composite materials, the compatibilization between clay minerals and polymer materials (clay organomodification) as well as the choice of the surfactant kind will be introduced in the following part.

Preparation of nanocomposite materials

With the aim of improving polymeric materials properties, numerous researchers studied the dispersion of compatible inorganic materials within the polymeric matrix. The addition of particles as fillers leads to improvement of the material thermal, mechanical or conductive properties such as stiffness and toughness, barrier effect or fire resistance. A large range of natural and synthetic fillers are available for their elaboration. (Table II -1). The pioneer work of the Toyota research group (1990) on polyamide 6 reinforced with alkylamonium-modified Montmorillonite (MMT) 84,85 opened the gate to the use of clays and layered silicates as polymer fillers. More particularly, polymer-layered crystal nanocomposites are a class of composite materials. These materials are obtained by the intercalation of the polymer within the particles layers. Such materials can be defined as nanocomposites when the dispersed clay particles are sized in the range of nanometres (Less than 100 nm). It is noteworthy that a homogeneous dispersion of clay is essential to an efficient reinforcement of a composite.

The percentage of clay needed to enhance the thermal and mechanical properties of polymer layered silicate nanocomposite is very low (2 to 5 wt %). As a consequence, a great advantage of these materials is their light weight.

Among the possible polymeric materials available for the elaboration of nanocomposites, the study of epoxy based polymeric matrix has been significant. Indeed, epoxy thermosets are broadly used in adhesives and coatings. Nevertheless, high performance applications are hardly reached with non-modified epoxy thermosets. [START_REF] Pascault | Epoxy polymers[END_REF] The elaboration of epoxy composites, by the incorporation of layered silicate filler particles, was shown to lead to an enhancement of the materials properties 86 and was thus widely studied. 83,[86][87][88][89][90] The mechanical properties of lamellar silicate-modified epoxies are strongly dependent on the fillers size, organophilic treatement and on their intercalation/exfoliation state within the final material. Through isomorphic substitutions of structural ions within the MMT sheets, a charge deficiency is created. Indeed, some ions within the platelet sheets can be replaced by lower charged ions.

For instance, Al 3+ can be replaced by Fe 2+ or Mg 2+ . The MMT platelets are thus globally negatively charged. Consequently, exchangeable counter-ions are present in the interlayer space between the platelets in order to insure the clay platelets electro-neutrality. The nature of the cations and their hydration are mostly determining the interlayer dimension. The interlayer distance between two platelets is described as a basal spacing d001. In the case of MMT clay the interlayer cations are essentially hydrated Na + and Ca 2+ , conferring a hydrophilic character to the MMT clay.

As polymeric materials, such as epoxies, are generally characterised by a hydrophobic behaviour, the modification of the clay minerals hydrophilic property is essential for adequate matrix-filler compatibility. Indeed, the properties of nanocomposite materials are strongly impacted by the morphology and the filler dispersion state within the polymeric matrix. 83,[START_REF] Bergaya | Handbook of clay science[END_REF] Depending on the polymer-clay compatibility several dispersion states can be obtained (Figure II -2). 83 with an improvement of the corresponding neat polymeric material properties. Nevertheless, the exfoliated state appears to be the most efficient in terms of mechanical and barrier properties enhancement [START_REF] Liu | [END_REF]96 and a particular attention has been paid to the understanding of the exfoliation mechanism of lamellar silicates, especially for MMT clay. 97,98 Indeed, in order to obtain an exfoliated structure it is essential to enhance the clay-polymer compatibility and to promote either the intercalation of the polymer chains or the in-situ polymerisation of monomers within the interlayer space. The surface modification of the clay mineral by an organic compound (organomodification) represents a widely studied approach. 88, 99

Clay organomodification strategies

Elaboration of MMT nanocomposites by direct polymer intercalation is hardly reached due to their discordant properties. Indeed, most of the polymers are hydrophobic whereas pristine MMT clay is hydrophilic due to the presence of hydrated metallic cations within the sheets interlayer space. The elaboration of MMT nanocomposites requires thus the clays organomodification. For the last two decades, many works report on the investigation of MMT exfoliation mechanism in polymers and how to drive them. [START_REF] Bergaya | Handbook of clay science[END_REF]98,100 Through its particular structure composed of lamellar sheets, the MMT modification to hydrophobic/more organophilic compound is easily achievable. Clay organomodifications can be achieved predominantly by two processes: (1) a non-covalent grafting (by a cationic exchange of the interlayer cations with cationic surfactants) or ( 2) a covalent grafting (reactive groups towards the polymer are bonded on the edge or on the surface of the clay platelets). 101

In the following part, we will mainly focus on the clay organomodification strategies for the reinforcement of epoxy resins.

Clay organomodification by cationic exchange reaction

MMT clay organomodification is generally achieved by cation exchange reaction. Indeed, the interlayer cations insuring electronegativity of the materials are easily exchangeable, particularly with organic ammonium or phosphonium-based surfactants. 100,102,103 These alkylammonium or alkylphosphonium cations allow lowering the surface energy of the clay minerals galleries and the wetting properties of polymer matrices towards the organomodified MMT are thus improved.

The most used cationic surfactants for the organomodification of MMT clay as filler for epoxy nanocomposites are ammonium-based surfactants, particularly quaternary ammonium ones.

Indeed, the hydration of quaternary ammoniums is lower than those of primary ammoniums and their desorption is thus minimized. Notwithstanding, an exfoliated state is hardly reached if an additional chemical catalysis is not provided. 104 Indeed the polymer growing or networking kinetics must be higher within the clay mineral interlayer spaces compared to outside otherwise there might be a rate competition between the platelets exfoliation and the polymer matrix gelation during polymerization. 105 Indeed, when the polymerization rate is higher in the interlayer galleries than in the outside, the formation of an intragallery polymer network is firstly Beside the compatibility enhancement provided by the cationic exchange with surfactants, clay minerals could also be made compatible towards epoxy precursors. Indeed, when the clay is modified with amine, anhydride or carboxylic groups for instance, the epoxy monomers could react with the reactive groups and the polymer network could grow within the interlayer space. [START_REF] Pascault | Epoxy polymers[END_REF] To this aim, several researchers modified MMT clay for instance by covalent grafting of organosilane compounds with various functionalities onto the hydroxyl groups on platelet surfaces or edges. The grafted organosilanes may be reactive toward epoxy polymers for example if they are bearing amine, anhydride or carboxylic groups. [108][109][110][111] Nevertheless, Le Pluart et al. 108 highlighted the possible reaction of covalent grafted organosilanes on the layer edges between themselves leading to a collapse of the mineral layers and preventing their exfoliation. The clay organomodification by cationic exchange prior to the covalent grafting of functionalized organosilane compounds should be favoured. Indeed, the prior organomodification would increase the interlayer spacing, helping thus the diffusion of the organosilane compounds (and afterward epoxy monomers) within the interlayer space and favouring thus their covalent grafting on the platelets surfaces and afterwards the platelets exfoliation.

As described previously, the clay organomodification by a cationic surfactant is essential to change the clay hydrophilic character to a more organophilic character, as well as to enhance the clay platelets interlayer space. On the other hand, the covalent grafting of functionalized organosilane compounds onto the clay platelets allow the easy introduction of reactive functions towards epoxy compounds, favouring their polymerization within the clay platelets. Moreover, the good dispersion of sepiolite clay needles within the polymeric matrix led to an enhancement of the material thermo-mechanical properties. Indeed, the Tg was shifted to higher temperature (from 180 °C to 195 °C) and the storage modulus was increased from 4.0 to 4.8 GPa at 50 °C.

Based on these previous results, three different ammonium surfactants were prepared from epoxidized cardanol NC-513. In a first time the effect of the cardanol-based surfactants on the Montmorillonite clay organomodification was investigated. Then, their amino group content and reactivity towards the BADGE epoxy matrix were studied as a benefit or a drawback to the exfoliation of MMT layered clay mineral within a BADGE epoxy matrix. Indeed, the surfactant activity towards BADGE could either help the MMT layer exfoliation or even aggregate those. 112 These results are presented in the following section.

Results and discussion

The detailed experimental conditions are reported in annex p181. The FTIR spectra of all CardSx materials were very similar, as expected due to their close chemical structure.

The signal due to the aromatic protons at δ= 6.50-7.25 ppm was used as integration reference for 4H. The expected theoretical integrations were calculated by moderation based on the abundance of unsaturation described in the literature. 11 are based on a previous work 50 and from a study on Cardanol-issued polyurethane resin described in reference. 70 To simplify, the experimental and theoretical integrations will be noted For each surfactant, the characteristic peaks of cardanol were observed, especially the aromatic protons [1, 2, 3, 4] II -2. As it can be observed, the experimental integrations of the peaks corresponding to the cardanol moiety were close to the expected integrations for a mono-addition of NC-513 on TAEA.

Beside the characteristic peaks from the cardanol moiety, the reaction of the NC-513 epoxy group with the TAEA amine to yield CardS1 was confirmed by the presence of peaks at 3. 84-4.23 ppm corresponding to H in α to oxygen [5, 6]. Their integration corresponds to an opened epoxy cycle as they integrated for Iexp = 3.5 H (Ith = 3 H). Furthermore, peaks corresponding to the TAEA compound were also readily observed. The peaks at 2.28-2.95 ppm, Iexp = 15.6 H, Ith = 16.1 H, corresponded to the CH2 [7, 8, 9, 10, 11] of TAEA combined to the CH2 between two unsaturations of NC-513 [c3, f3]. The primary amines of TAEA [12] The characteristic peaks from the cardanol moiety were also observed for the CardS2 compound

(Figure II -11).
The experimental integrations were very close to those of the theoretical integrations and to the integrations found for CardS1. (Table II -3) The mono-addition of NC-513 on EDA was confirmed by the integrations and the presence of te peaks at 3.86-4.30 ppm, Iexp = 3.4 H, Ith = 3 H, corresponding to reacted epoxy ring protons in α of oxygens [5, 6], the peaks at 2.47-2.93 ppm corresponding to the CH2 [7, 8, 9] of EDA combined to the CH2 between two unsaturations of NC-513 [c3, f3] for which Iexp = 8.5 H and Ith = 8.1 H, and the peak at 3.18 ppm, Iexp = 2.5 H, Ith = 2H corresponding to the NH2 of EDA [10]. Finally for the CardS3 compound, the peaks corresponding to the cardanol moiety were also observed on the NMR spectra, and their integrations were consistent with a mono-addition of NC-513 on an amine compound such as for CardS1 and CardS2. (Table II -4).

The mono-addition of NC-513 on DMEDA was further confirmed by the following peaks: the CH2 [7, 8, 9] of DMEDA combined to the CH2 between two unsaturations of NC-513 [c3, f3] for which Iexp = 13.6 H and Ith = 14.1 H, the protons of reacted epoxy ring protons in α of oxygens [5, 6] For all the characterized compounds, the experimental integrations were slightly varying from the expected integrations. This is due to the fact that cardanol is a natural-occurring compound

The mass for each Cardanol-based surfactant were in accordance with their expected structure, and the protonated mono-addition compounds of NC-513 on the various amine-containing reagents were the main detected compounds. Additional MALD-MS analyses using DCTB as matrix were achieved in order to validate the structural features of the obtained surfactants and to highlight their available amine functionalities. Indeed, DCTB is known to react with primary and secondary amines both in solution and in the gas phase, to produce molecule-matrix adducts, characterized by +184 Da shifted peaks (proportionally to the number of N-H bonds). 113 In this reaction, an amino group of as the major product, indicating that the protonated CardS3 surfactant within MMT was not able to react with Fge. However, a unique addition of Fge is surprisingly detected at m/z 597. This addition of Fge was not expected from the CardS3 composed of a secondary and a tertiary amine (f =1). Indeed, the protonated surfactant should not be able to react anymore as the protonation is known to preferably occur on secondary amines (more basic than primary amines).

Nevertheless, the low abundance of this peak revealed the very poor reactivity of CardS3 towards

Fge. The mono-addition product of Fge on CardS3-MMT could be explained by the reactivity of the secondary amine towards Fge in its neutral form, influencing the protonation equilibrium.

In conclusion, CardS3-MMT seemed not to be able to react with epoxy groups because the protonated CardS3 specie was in majority detected. A higher reactivity towards Fge was observed for the CardS2-MMT and CardS1-MMT samples, as the protonated surfactants were no longer detected in the associated MALDI-MS spectra (expected at m/z 415 and 501 respectively). Indeed, the detection of the Fge-grafted surfactants within O-MMT clay by MALDI-MS analysis confirmed that the synthetized CardS1 and CardS2 surfactants contained available amine functionalities free to react towards epoxy after the organomodification procedure. Furthermore, the expected difference of the surfactants reactivity related to their amine content and nature could also be observed. Indeed, the protonated CardS1 compound (f = 4) was able to react three times with Fge, and protonated CardS2 (f = 3) reacted two times with Fge. As expected, the CardS3 compound (f = 1) reacted almost not with Fge. The surfactants could thus be classified according to their available amine functionalities (AAF) able to further react with epoxy after organomodification: In sum, a deeper clay exfoliation was expected during epoxy-amine polymerization process giving the nanocomposite material at the end. That is why the available amine functionality content of each surfactant, once situated within the MMT clay, was investigated. Indeed, as it could be observed by MALDI-MS analysis, the surfactants seemed to display a different reactivity according to their environment (without or within the clay platelets). To verify the available amine functionality content of the surfactants within the clay, furfuryl glycidy ether (Fge)

CardS1 (AAF = 3) > CardS2 (AAF = 2) > CardS3 (AAF <1).
compound was grafted to the surfactants, and the Fge-grafted surfactants were detected by MALDI-MS characterization. As expected, more Fge units were grafted to the surfactants with higher amino group content. Nevertheless, available amine functionality (AAF) of the surfactants within the clay were found to be lower than those of the neat surfactants: systematically to infinite molecular weight cross-linked polymers due to their higher functionality. 126,127 The use of di-Bz monomers for the elaboration of high performance materials is in consequence widely preferred to m-Bz monomers. The reinforcement strategy of PBz resins generally relies on extensively used polymer fillers as polyhedral oligomeric silesquioxanes (POSS), [134][135][136] clay minerals, [137][138][139][140][141] or carbon nanotubes. 142- 146 Recent works on carbon nanotubes (CNT)/polybenzoxazines composites raised interests onto convenient composites preparations based on π-π supramolecular interactions leading to good reinforcement of the PBz materials. 142,143,146 Nevertheless, the thermo-mechanical properties of PBz/CNT composite materials were moderate and strongly dependent on the functionalization of the CNTs fillers. 136 For nanocomposite compounds containing 5 wt% of CNTs, the Tg and storage modulus of M1based PBz material remained unchanged, whereas a significant improvement was observed for M2-based PBz materials. Indeed, the Tg of the M2-based PBz material was shifted by 50 °C to higher temperatures, and the onset of its thermal degradation was shifted from 250 °C to 300 °C.

CardS1 (AAF = 3) > CardS2 (AAF = 2) > CardS3 (AAF <
These results were correlated to strong supramolecular filler-matrix π-π interactions.

Regarding clay minerals, a traditional organomodification approach is employed to promote clay dispersion in Bz. As defined in the previous chapter, this strategy relies on the exchange of the clay inter-platelets cations by a reactive and organophilic cation to enhance the diffusion of Bz monomers within the clay platelets galleries and therefore favouring the polymer growing to reach an exfoliated state. 140,141,147,148 Conscious of the strong interactions driving the properties of PBz networks, it appears clear that using supramolecular interactions for the reinforcement of PBz matrix is a facile and efficient strategy.

Motivated by these approaches and in order to study the interaction between pristine clay and PBz resins, prior to clay organomodification, we proposed to study the supramolecular interaction between kaolin and poly(EDBz). 149 Indeed, kaolin is a common raw material which main component is kaolinite, a 1:1 clay mineral composed of single layers with a SiO4 tetrahedral network connected to Al(O, OH)6 octahedral networks with platy particle of hexagonal symmetry.

The layers are held together via hydrogen bonds, dipolar interactions and attractive Van der Waals forces, which results in a low intrinsic inner surface reactivity. Isomorphic substitutions within the layers generate negative charges that are counterbalanced by alkali cations (Na + and K + ) situated at the interlayer. Such cations are known to catalyse Bz crosslinking reactions. 150 Thus, due to its intrinsic interactions, kaolin appears as an adequate candidate to form for the polymerization resulted in materials with higher Tg and higher char yield. Particularly when Lewis acids such as PCl5, PCl3, POCl3 and TiCl4 were used, Tg's higher than 200 °C were recorded. Furthermore, char yields around 50 % were recovered from TGA analysis. The use of catalysts could thus be interesting for the elaboration of thermal protection materials. In conclusion a broad variety of catalysts may be used for the ring opening polymerization of Bz monomers at lower temperature.

Beside their effective catalyst activity, the majority of the catalysts appear to be petroleum-based and/or toxic. MgCl2 and ZnCl2 were evaluated as a safer alternative and as new catalysts to reduce the polymerization temperature of a (cardanol/aniline)-based Bz monomers, which usually polymerize at elevated temperature (around 260 °C). 156 As it can be observed in Table III As it can be seen in Table III -2, small amounts of monocarboxylic monomer induced a reduction of about 20 to 30 °C of the polymerization temperature which was even more important when the amount of carboxylic-containing co-monomer increased. For over 25 % of co-monomer amount, the polymerization temperatures were even lower than for m2 or m3 alone. In comparison, mixtures with dicarboxylic monomer m4 were reported to have a stronger catalytic effect. Indeed, with 5 % of m4, the temperature of copolymerization with m1 was decreased by 50 °C. When comparing the Tg of the copolymer PBz materials, it could be observed that materials obtained from carboxylic-containing Bz monomers tended to have higher Tgs than m1 based PBz materials. These results were most probably due to higher crosslinking due to hydrogen bonding with increasing content of cardboxylic acid functions. The structure-to-properties relationship is similar for Class A and Class B di-Bzs. The rigidity or the electronic state of the bridging group has a similar impact. Nevertheless, class B di-Bz monomers, i.e. phenols bridged with a diamine, are of major interest owing to their versatile synthesis and the numerous mono-phenolic and diamine reagents available. Nevertheless, the nature of the diamine bridging group is strongly affecting the synthesis conditions and the thermal properties of Bz monomers and corresponding PBz resins. 159-161 162-164 Furthermore, the nature of the substitution of the phenolic compound drives particular functionality of the Bz monomers, 159, 165-167 such as functional groups promoting the thermal activation of the ROP or increasing the crosslinking density of the resulting PBz materials.

Co

In the coming paragraphs, we will only focus 168 It was evidenced that the electron donating effect of bridging groups such as -CH2 or a single bond promotes the formation of the Bz oxazine ring. On the contrary, the withdrawing effect of bridging groups such as -CO or -SO2 stabilizes the mesomeric form of the phenolic groups, and thus decreases the capacity of bisphenol to close the oxazine ring. Similarly, the electronic effect of the diamine bridging group is also affecting the oxazine ring synthesis.

Indeed, the basicity of the primary amines is an important factor for the Bz monomer synthesis. 169 Hence, an electron withdrawing effect of the diamine bridging group will tend to lower the amino group basicity, impeding the Bz oxazine ring closure. On the contrary, electron donating effects of the diamine bridging group will enhance the basicity of the primary amino groups, promoting the Bz oxazine ring formation.

Flexibility of the bridging diamine

The flexibility of aliphatic diamines is also impacting the reaction conditions of the monomers synthesis. The effect of the chain length of aliphatic diamines as bridging groups was investigated. 162 The reaction times of the Bz monomer synthesis with increasing diamine chain length, from short and relatively rigid ethylenediamine to long and relatively flexible 1,12diaminooctane, are listed in Table III -3.

Monomer Diamine Reaction Time (h) P-ad2

H2N-(CH2)2-NH2 Ethylene diamine 1.5

P-ad4

H2N-(CH2)4-NH2

1,4-diaminobutane 4

P-ad6

H2N-(CH2)6-NH2

1,6-hexane diamine 8

P-ad8

H2N-(CH2)8-NH2

1,8-diaminooctane 10

P-ad12

H2N-(CH2)12-NH2

1,12-diaminododecane 12

Table III -3. Reaction times of synthesis of Bz monomers in CHCl3 at reflux with increasing diamine chain length. 162 It was evidenced that a short length diamine allowed a faster and easier monomer formation than a long chain diamine. 162 As it can be seen in Table III -3, the reaction times were shifting from 1.5 h to 12 h while increasing the diamine chain length from 2 to 12 carbons. Low reaction times are thus favoured by short length diamine bridging groups such as ethylenediamine.

Thermal properties of Class B di-Bz monomers and PBz resins

As related by numerous studies, the flexibility and chain length of the diamine bridging groups are largely determining the thermal properties of the di-Bz monomers and their corresponding PBz materials.

Flexibility and chain length of the bridging diamine

As PBz resins are mainly intended for high performance applications, aromatic diamines that stand as rigid bridge have been widely used for the design of di-functional Bz monomers, hereafter known as aromatic-di-Bz. These rigid bridging groups, inspired from the development In conclusion, the synthesis of aromatic-di-Bz monomers yielded to compounds with relatively high melting temperatures, and to aromatic PBz with high Tg. On the contrary, flexible bridging groups (aliphatic diamines) allowed the synthesis of low melting temperature aliphatic-di-Bz monomers, with a wide processing window. Nevertheless, the higher flexibility of the aliphatic bridging group impedes the Tg of the materials, underlining the difficulty to find a compromise for the design of high performance materials with moderate processing conditions.

Additional functional groups

The introduction of some functional groups has been tentatively considered to promote lower thermal activation or to improve the properties of the resultant PBz materials.

The effect of the allyl group of o-allylphenol on Bz monomers prepared with various diamines was studied. 159,166,165 However, despite a lowering of the polymerization activation temperature, the presence of the allyl group on the phenolic ortho position hampered the polymerization process of the benzoxazine, resulting in lowering the crosslinking density of the networks.

Maleimide functional groups, were shown to enhance the PBz materials thermal properties. In summary, class B di-Bz monomers are considered as the most appropriate and versatile structures for the synthesis of novel high performance PBz materials. The choice of the diamine strongly affects the synthesis conditions, yields, thermal properties and polymerization kinetics of class B di-Bz monomers and of their corresponding PBz materials. First of all, a moderate/wide processing window is important for the easy elaboration of PBz materials. As aromatic-di-Bz monomers were characterized by high melting temperatures and narrow processing windows, the use of an aliphatic diamine should be preferred for the synthesis of di-Bz monomers easier to process due to their wide processing windows. Furthermore, even though the melting temperature of Bz monomers decreased with increasing the aliphatic diamine chain length, their Tg was clearly shifted to lower temperatures, lowering the thermo-mechanical properties of the resulting PBz materials. In addition, the synthesis of Bz monomers with long aliphatic chains was reported to be distinctly more difficult. As a result, short aliphatic diamine bridging groups, such as ethylene diamine, should be preferred for the synthesis of di-Bz monomers displaying moderate processing windows therefore resulting in high crosslinked PBz materials with good thermal and mechanical properties.

Vanillin

Vanillin is a phenolic compound with an ortho methoxy group and a para formyl group, historically produced through extraction from vanilla seedpod but stems industrially mostly from the processing of lignin. 3,171 Due to the high abundance of sustainable lignin resources, 172,173 vanillin appears as a promising substitute to oil-derived phenolic compounds or polymer building-blocks. [174][175][176][177][178] Its use as a precursor for the synthesis of bio-based Bz monomers was recently studied. 179,180 The formyl group contained in the vanillin compound is of great interest for the synthesis of biobased Bz monomers. Indeed, with the appropriate stoichiometric amount of reagents and through a convenient order of their introduction and reaction, the aldehyde function is not consumed during the synthesis. This function is thus considered as an additional reactive group on the Bz monomer, able to further react with other chemical compounds or to increase the material crosslinking density.

The chemical structures as well as the thermal properties of vanillin-based Bz monomers and their corresponding materials, reported in the literature, are summarized in Table III - III - These lignin-derivative compounds, as well as their methylated equivalents (CAM, FAM and PAM respectively), were studied as precursor of mono-functional Bz monomers (Table III -8 while with cardanol, the polymerization temperature were reported to be higher (between 230 °C and 260 °C). The higher polymerization temperatures were certainly due to the steric hindrance brought by the side chain, impeding the polymerization upon curing. Hence, the molding and shaping of cardanol-based Bz monomers is facilitated by a wide processing window, but their overall processing is strongly hampered by high polymerization temperatures (< 230 °C).

Furthermore, it is noteworthy that the thermo-mechanical properties of these PBz materials were almost never characterized by DMA analysis, as it is very difficult to obtain self-supported materials due to the steric hindrance of alkyl side chain, yielding to low molecular weight polymer. Thus, the glass transition temperatures of short amine based PBz reported in the literature were obtained from DSC analysis (Table III -11, lines 6 to 9). They are found to be very low, from 36 °C to 60 °C. Bz with low melting temperatures. From previous studies, 196 it was expected that cardanol could be a good candidate to design asymmetric Bz monomers with vanillin to obtain low melting temperature Bzs and thus expand the processing window. Indeed, the cardanol alkyl side chain provides better processability and flexibility to the material through internal plasticization.

Furthermore, the presence of the alkyl chain causes steric hindrance, lowering thus the compound reactivity. Indeed, it was observed that the synthesis of di-vanillin Bz monomer was straightforward and fast whilst the synthesis of di-cardanol was rather slow. The steric hindrance brought by the cardanol side chain impeded also its polymerization upon curing, as indicated by the low enthalpy recorded in DSC for the di-cardanol Bz monomer (32.5 J/g versus 121 J/g for divanillin) as well as the formation of a loosely crosslinked network. Indeed, the steric hindrance brought by the alkyl chain lead to material with low molecular weight, as attested by the difficulty to obtain material from di-cardanol Bz that does not creep above Tg.

Results and discussion

The detailed experimental conditions are reported in annex p 181. The structural features of the obtained products were characterized by 1 H NMR and HRMS. respectively. Furthermore, the signal integrations were confirming the structure of the dibenzoxazine from phenol and EDA. The signal of the aromatic protons [1,2,3,4] at δ = 7.15 -6.78 ppm was taken as integration reference and should integrate for 8 H. Thus, the integrations for the peaks corresponding to O-CH2-N [6] and Ar-CH2-N [5] were found to integrate for Iexp = 3.73

H and Iexp = 4.02 H respectively as expected (Ith = 4.00 H for each peak). The signal corresponding to EDA [7] was also observed at δ = 3.02 ppm and Iexp = 4.08 H (Ith = 4.00 H). The 1 H NMR analysis confirmed the expected chemical structure of the di-phenol Bz monomer. The chemical shifts, as well as their experimental and theoretical integrations are summarized in Table III -13.

function [7] appeared at δ = 9.81 ppm with Iexp = 2 H (Ith = 2 H). The integration of aromatic proton of vanillin [1, 2] at δ = 7.13-7.32 ppm further confirmed the presence of two vanillin moieties (Iexp = 1. 99 H and Ith = 2.00 H). Peaks corresponding to EDA [5] were also observed at δ = 3.02 ppm where Iexp = 3. 70 H (Ith = 4 H). Furthermore, characteristic peaks at δ = 4.13 ppm and at δ = 5.08 ppm, which correspond to the Ar-CH2-N [3] and to O-CH2-N [4] protons respectively, indicated the formation of di-Bz monomer from vanillin. All the expected theoretical integrations as well as the corresponding experimental integrations for the di-vanillin monomer are reported in Table III -Di-cardanol benzoxazine monomer

Similarly, the structure of the di-cardanol Bz monomer was confirmed by the 1 In regard to the integration of the NMR signals relative to the cardanol compound, the precise integration depends obviously on the composition of cardanol and related proportion of different isomers. The integrations are usually calculated by moderation based on the abundance of unsaturation described in the literature. 11,51,[204][205][206] These unsaturation abundances can slightly vary regarding the origin and the processing of raw Cardanol extracted from CNSL. As such the integration may diverge from sample to other. The unsaturations abundances of the used cardanol were considered as following: tri-unsaturated (n=3) ~ 41%, di-unsaturated (n=2) ~ 23%, mono-saturated (n=1) ~ 34%, saturated (n=0) ~ 3%. 11,50,[204][205][206] In addition, the difference of relaxation times between aromatic and aliphatic hydrogen may complicate the accurate quantification of all protons. Therefore, the peaks related to the aliphatic chain of cardanol were integrated to the aliphatic hydrogen in β position of the cardanol aromatic ring, which should integrate for 2H.

Figure III -26. 1 H NMR spectrum (in CDCl3) of di-cardanol benzoxazine monomer.

The characteristic peaks of cardanol were observed, especially the aromatic protons [1, 2, 3] at δ = 6.60 -6.88 ppm which integrate each for about 2 H (see Table III - The formation of the benzoxazine structure was verified by the presence of benzoxazine characteristic peaks at δ = 4.03 ppm and at δ = 4.89 ppm corresponding to Ar-CH2-N [4] and to O-CH2-N [5] respectively, both peaks integrating as expected for approximately 4.00 H. In conclusion, the synthetized compounds appear to be pure as confirmed by the MALDI/TOF-MD and HRMS characterizations.

Chemical

Characterization by DSC and TGA

The thermal behaviour of the symmetric monomers was investigated by DSC and TGA analyses.

For each monomer, the DSC and TGA analyses were carried out at a heating rate of 20 K/min under nitrogen atmosphere.

-Di-phenol Bz monomer

The DSC and TGA analysis of the di-phenol monomer are displayed in Furthermore, it can be observed on the TGA analysis that the monomer was able to polymerize at elevate temperatures, around 210 °C, before undergoing thermal degradation (T5% = 287 °C). -Di-cardanol Bz monomer

In contrary to the di-vanillin compound, the di-cardanol Bz monomer exhibited a low melting temperature of Tm = 44 °C. This result is most probably due to the presence of the C15 alkyl side chain in meta position. Indeed, cardanol is well-known to provide flexibility to materials through plasticizing effect. The polymerization temperature was found to be at Tp = 219 °C, within the expected polymerization temperature range of di-Bz monomers. The di-cardanol Bz monomer presents thus the advantage of a very large processing window.

Furthermore, when comparing the DSC and TGA analysis (Figure III -35), it can be observed that the di-cardanol Bz monomer thermal degradation occured at higher temperature than its ring opening polymerization temperature. Indeed, T5% = 260 °C whereas Tp = 219 °C, indicating that the monomer is able to polymerize without early thermal degradation. Moreover, it can be noted that the thermal degradation temperature for the di-cardanol Bz monomer was much higher than the degradation temperature of the di-vanillin Bz monomer (T5% = 203 °C). The behaviour of di-cardanol upon heating is typical to thermosets with a significant increase of both G' and G'', evidencing the starting of the crosslinking at 190 °C. The gelation time, was observed in the range of [30-31] min highlighting the low reactivity of di-cardanol Bz monomers.

In conclusion, cardanol di-Bz monomer was found to display a large processing window (ΔTproc = 175 °C) due to very low melting temperature (Tm = 44 °C), which makes it an interesting precursor for easily processable bio-based Bz. Indeed, when comparing to the di-phenol Bz monomer (Tm = 115, ΔTproc = 97 °C), the presence of the cardanol alkyl chain seemed to favorise lower melting temperatures, probably due to sterical hindrance. However, the steric hindrance brought by this side chain seemed to impede its polymerization upon curing as indicated by its very long gelation time [30-31] min at 190 °C recorded in rheology experiments (di-phenol Bz monomer Tgel = [4-5] min at 190 °C) and low enthalpy recorded in DSC (22.6 kJ/mol versus 49.9 kJ/mol for di-vanillin Bz for example).

In consequence, the di-cardanol Bz monomer is interesting because of its low melting temperature but the corresponding PBz material elaboration is nevertheless impeded by a long gelation time and steric hindrance resulting in a poorly crosslinked polymer material. The use of the di-vanillin Bz monomer to synthesize a self-standing PBz material on the contrary is hindered by a too high melting temperature overlapping its polymerization and thermal degradation.

However, the good thermal properties of di-vanillin PBz due to the aldehyde function of vanillin Bz are very encouraging.

Thus, we propose an innovative strategy to lower vanillin-based Bz monomers melting temperatures in order to enable their processing. Cardanol was shown to provide, through plasticizing effect of the C15 alkyl chain, flexibility to the resulting materials and to result in Bz monomer with low melting temperature. More importantly, the low reactivity of cardanol driven by its structural features offers therefore the possibility to control the synthesis of a monocardanol Bz with a free primary amine moiety that can be further coupled with another bio-based phenol like vanillin. We propose in the following part a synthesis of asymmetric monomers combining cardanol and vanillin displaying low melting temperature and accessing PBz materials with good thermo-mechanical properties. As previously mentioned, the precise integration of the NMR signals corresponding to peaks relative to the cardanol compound, depends on the composition of cardanol and related proportion of different isomers. The integrations are usually calculated by moderation based on the abundance of unsaturation described in the literature. In addition to varying unsaturation abundances, the difference of relaxing times between aromatic and aliphatic hydrogen may complicate the precise quantification of all hydrogen from this asymmetric monomer.

An accurate integration was optimized where the -OCH3 function from the vanillin compound was taken as integration reference for the peaks corresponding to the benzoxazine structure. This peak should integrate for 3 H. As the cardanol alkyl chain unsaturation degree is varying and the relaxation times are differing from the other hydrogens, the related peaks will be integrated on another reference. The aliphatic hydrogen in β position of the cardanol aromatic ring was taken as integration reference and should integrate for 2 H. First of all, the characteristic peaks of cardanol were observed, such as the aromatic protons [1, 2, 3] at δ = 6.60 -6.88 ppm which integrate each for about 1 H (see Table III - For the vanillin moiety of Vani-Card Bz monomer, the peak corresponding to the -OCH3 function of vanillin [13] at δ = 3.86 -3.94 ppm was chosen as integration reference. This peak should integrate for 3H (I = 3 H). The characteristic peaks corresponding to the vanillin compound moiety were revealed in the NMR spectrum. The hydrogens from the aldehyde function [11] appeared at δ = 9.81 ppm with Iexp = 1.01 H (Ith = 1.00 H). The integration of aromatic proton of vanillin [10, 12] at δ = 7.12 -7.34 ppm further confirmed the presence of one vanillin moiety (Iexp = 1.00 and 1.01 H and Ith = 1.00 and 1.00 H). Peaks corresponding to EDA [6, 7] were also observed at δ = 2.95 -3.09 ppm where Iexp = 3.99 H (Ith = 4.00 H).

Furthermore, characteristic peaks at δ = 4.01 ppm and δ = 4.13 ppm assigned to Ar-CH2-N of cardanol- [4] and vanillin-based [9] oxazine moieties respectively were detected, as well as at δ = 4.88 ppm and δ = 5.08 ppm assigned to O-CH2-N of cardanol- [5] and vanillin-based [8] oxazine moieties respectively, attesting the formation of an asymmetric di-Bz monomer from vanillin and cardanol. The cardanol side chain had a clear plasticization effect on both materials (symmetrical and asymmetrical based on cardanol) as compared to the Tα of poly(di-phenol) (160 °C), but resulted in a thermoplastic material in the case of poly(di-cardanol). The substitution of one unit of cardanol by vanillin within the monomer allowed a sufficient increase of the Vani-Card PBz crosslinking density to yield a self-supported thermoset material.

Chemical

In addition, the vanillin formyl group within the material should increase the material stiffness most probably through the formation of strong intra-and inter-molecular H-bonding. The storage modulus in the glassy state also increased from 150 MPa for poly(di-cardanol) to 700 MPa for poly (Vani-Card). These values of storage modulus seemed to be similar to those described in the literature. Ishida and Agag reported a storage modulus of 450 MPa in the glassy state for a polybenzoxazine prepared from CNSL and aromatic 4,4'-diaminophenyl methane. 211 In spite of the aromatic diamine used by the authors, poly(Vani-Card) enabled to reach a material with higher stiffness due to the presence of the vanillin moiety. In conclusion, the TGA analysis of the symmetric and asymmetric PBz materials highlighted the increase of the thermal degradation temperature for PBz materials containing at least one cardanol moiety (poly(di-cardanol) and poly(Vani-Card)). The asymmetric Bz monomer enabled thus, through a processing point of view, an easy elaboration of a cardanol-and vanillin-based PBz material. Furthermore, the synthesis of the asymmetric Vani-Card monomer was also shown to strongly influence the reactivity of the monomer. Indeed, the di-cardanol Bz monomer displayed a long gelation time (Tgel = [30-31] min at 190°C) in comparison to a classical di-phenol Bz monomer (Tgel = [4-5] min at 190°C). In the case of Vani-Card Bz, an interesting moderate gelation time of 8-9 min was reported.

Moreover, the characterizations of the asymmetric PBz material highlighted the obtaining of a thermoset material with good thermo-mechanical properties. Indeed, a Tg of 129 °C and a storage modulus in the glassy state of 700 MPa were reported, indicating that Vani-Card PBz material displayed very comparable thermal and mechanical properties to other known polybenzoxazines particularly those partially or fully based on renewable compounds.

Finally the presence of the cardanol moiety was shown to strongly influence the thermal stability of the PBz material. Indeed, a high thermal degradation onset temperature was recorded for Vani-Card PBz material (T5% = 373 °C) compared to classical di-phenol PBz material (T5% = 273 °C).

This versatile approach is a powerful tool to access a wide range of bio-based asymmetric benzoxazines given the large number of precursors available and their possible combination. It paves the way toward easily processable high performance bio-based benzoxazines. This strategy could for example be applied to further improve the processing of bio-based di-Bz monomers.

Indeed, the high polymerization temperature of Bz monomers remains a major drawback for their spreading for industrial applications. The use of lignin-derivative phenolic compounds bearing a carboxylic acid function for the synthesis of mono-Bz monomers were recently reported by Comi et al. 184 . The presence of the -COOH function was reported to induce a lowering of the Bz ring opening polymerization temperature. However, among others, the main drawback of these monomers was there to high melting temperature, close to their polymerization temperature, hindering the processing of the materials. The synthesis of asymmetric monomers between cardanol and bio-based phenolics bearing carboxylic acid functionalities could be an interesting method to lower the polymerization temperature of the Bz while facilitating their processing.

Chapter IV: Interpenetrating Polymer Networks (IPN) from a cardanol-based thermoset network

1 Introduction
Nowadays, the use of conventional petroleum-based epoxy thermosets is being compromised not only for the foreseen shortage in oil resources, but also because widely used components such as Bisphenol A (BPA), identified as an endocrine disruptor, wreak havoc on the human health. This The chemical structure of CDGE pre-polymer was fully characterized by NMR analysis, 13 as well as by size exclusion chromatography (SEC) and MALDI mass spectrometry. 204,212 The resulting materials properties were also studied.

The NMR analysis of the CDGE pre-polymer allowed the determination of its unsaturation composition. CDGE contains predominantly saturated chains (95 %) and mono-olefinic chains ( 5%) as illustrated in The most suitable ratio between CDGE and IPD was 1 g of CDGE and 0.13 g of IPD, leading to a material with a Tg = 50 °C. The cardanol alkyl chains act as a plasticizer and soften the network.

When Jeffamine D400 was used in lieu of IPD, the best epoxy/amine ratio was 1 g of CDGE and 0.29 g of Jeffamine, yielding to a material with a very low Tg = 15°C. The CDGE network Tg is thus highly affected by the Jeffamine diamine flexibility. These results were supported by the determination of the networks crosslinking densities (ʋe) from the storage modulus at 60 °C above the Tg, determined by DMA (Table IV CDGE epoxy pre-polymer was also studied to substitute BADGE for the elaboration of epoxy thermosets for adhesive applications. 215 The adhesive and thermo-mechanical properties, as well During these tests, the assemblies were exposed to water at 80 °C during 4 h and the adhesion strength was measured after this exposition. Interestingly, neat CDGE/DAC epoxy network displayed after this test a high adhesive strength (4.5 MPa), even higher than dry neat BADGE/DAC network adhesion strength (4 MPa). Thus the more sensitive to water is the network, the lower is the adhesion strength after wet cataplasm test. Indeed, higher strengths were due to better surface wettability (Contact angles values obtained by elliptic calculation method: 66 ± 2 °for BADGE and 51 ± 1 ° for CDGE) leading to stronger aluminium-epoxy joints.

These results are highlighting the interesting properties of CDGE-based materials to substitute Bisphenol A diglycidyl ether in adhesive applications in wet environments. However, in spite of this relatively high resistance to water, certainly linked to the very limited hydrolysis of CDGE network compared to BADGE, CDGE swells too much in water. Even if the impact on the Tg is very low, one can imagine that 5 % volume change would be problematic for a lot of applications. The addition of fillers, like clay of expanded graphite, is a well-known approach that would limit the diffusion of H2O molecules within the network. In this work, we decided to consider another approach based on a macromolecular reinforcement. The following parts are focusing on the state-of-art of the macromolecular reinforcement of epoxy networks, and more particularly on the use of benzoxazine. This approach is nevertheless limited to systems containing a major part of benzoxazine. Indeed, a too high amount of epoxy groups would lead to a decrease of the crosslinking density due to unreacted or small molecular weight epoxy acting as plasticizer within the PBz resin. Similar results were obtained by Jain et al.. 218 The activation of the Bz ROP by the BADGE compound is attested by the decreasing of the benzoxazine polymerization temperatures. Nevertheless, the Tg was also found to decrease with an increase of the BADGE amount.

Interestingly enough, these systems were shown to be very stable at high temperature since the polymerization was triggered by the oxazine ring opening that occurs around 150 °C for bisphenol-A based benzoxazine. Based on this property, Kimura et al. 219 developed a new epoxy precursor from the combination of BADGE and PBz stable at elevated temperatures for injection molding. The PBz cured BADGE thermoset displayed even a higher Tg (175 °C) than the BADGE thermoset cured with novolac (phenol-formaldehyde resin, Tg = 149 °C).

Epoxy materials are generally cured with multifunctionnal amines, and it is conceivable to use them in combination to benzoxazine. 216,[220][221][222][223][224][225][226][227] Several reactions described hereafter are likely to occur in these ternary systems, influencing the final material morphology and properties. Thermosets can be reinforced at the macromolecular scale by blending with a second polymer or by the formation of IPN. The IPN structure is considered as an interesting method for the reinforcement of epoxy materials as the properties of the two polymers are combined in a novel material displaying ideally a single glass transition temperature, witnessing the close vicinity of the two kinds of polymer chain. The single transition temperature, situated between the transition temperatures of the single networks, corresponds to the interpenetrating phase.

Nevertheless, IPNs show usually two transition temperatures, corresponding to the two phases induced by the polymer phase separation and enriched in one polymer network.

Epoxy materials are compatible with a wide range of thermoset polymers and are often coreactive. Epoxies have thus been blended with almost all the other families of polymers. Similarly, numerous studies report the toughening of epoxy resins by the formation of IPNs with polyurethane resins. [232][233][234][235] Isocyanate-terminated polybutadienes, 236 and polyesters, 237 were also considered for the improvement of epoxy properties.

IPNs were mainly used for the improvement of the elasticity, the brittleness or the adhesive strength of epoxy networks, while maintaining their good thermal properties. To this aim, the most commonly used polymers are polyurethanes 238 239 or bismaleimides. 240 Their incorporation within the epoxy thermosets allows the improvement of the materials flexibility and its thermomechanical properties. Owing to their excellent thermo-mechanical properties and high stiffness, polybenzoxazines could be used similarly to polyurethanes and bismaleimides to reinforce CDGE.

The poly(CDGE) single network crosslinked by DAC was shown to display low Tg at 40 °C and a 4

GPa storage modulus in the glassy state. 215 Furthermore, Verge et al. reported the high water uptake of 6 ± 0.2 wt% of a poly(CDGE) network with DAC as hardener, most probably due to its wide network meshes. On the contrary, the single poly(EDBz) network was shown to display relatively high Tg of 216 °C and high modulus (6-7 GPa). Furthermore, PBz materials are wellknown for their very low water uptake. 115 In consequence, the elaboration of poly(CDGE)/poly(EDBz) IPN was foreseen as a strategy to reinforce the properties of the poly(CDGE) network, while preventing the water diffusion by the presence of the poly(EDBz) network.

This chapter relates the elaboration of interpenetrating polybenzoxazine and epoxy/diamines networks. By this strategy, we expect to tackle the main issue from CDGE networks, i.e. the water uptake. Indeed, we envision that the "filling" of the wide mesh of the cardanol-based network by a PBZ prevent the water diffusion, in addition of clear reinforcement of the thermal and mechanical properties of the materials. As above mentioned, many competitions may occur within ternary benzoxazine/epoxy/amines systems and suitable conditions for the elaboration of IPN have to be found. They are detailed in the following paragraphs.

Results and discussion

The detailed experimental conditions are reported in annex p 181. As it can be observed, two distinct reactions will be favoured for the in-situ sequential IPN elaboration. In a first time the polymerization of the epoxy-amine network (poly(CDGE)) between CDGE and the suitable diamine hardener is expected, followed in a second time, by the ringopening polymerization of the Bz monomer forming the polybenzoxazines network. It is important to notice that any possible reaction between the Bz monomer and the diamine hardener is to avoid, leading otherwise to co-networks. The choice of a diamine hardener nonreactive towards the Bz monomer is thus to favour. Furthermore, it is well-known that Bz monomers polymerize at high temperatures, in the range of 200 °C to 220 °C. In consequence, the elaboration of the IPNs through the in-situ sequential synthesis is only possible if the epoxy-amine system cures at low temperature, whereas the PBz network cures at elevated temperature.

Moreover, the possible reaction between amines and Bz monomers have to be similarly avoided.

In conclusion, the choice of the diamine hardener is fundamental for the elaboration of poly(CDGE)/poly(Bz) IPNs. To this aim, the curing of CDGE with various diamine hardeners has been investigated by DSC analysis, as well as the curing of the Bz monomer in presence of the selected diamine. In conclusion, the formation of the first poly(CDGE) network by reaction between CDGE and IPD should be achieve at low temperature, followed by the formation of the second poly(EDBz) network at high temperature. By default, the CDGE monomer will always be reacted with IPD in stoichiometric ratio. Consequently, in the following paragraphs, in order to facilitate the materials denomination, the CDGE/IPD system will be noted CDGE (unreacted mixture of CDGE and IPD)

and the crosslinked network will be noted poly(CDGE) (crosslinked CDGE/IPD network).

Similarly, crosslinked network issued from EDBz will be noted poly(EDBz).

unreacted CDGE or EDBz monomers. The extracted content (EC) was given as a weight percentage:

EC (%) =

(𝑊𝑖-𝑊𝑒) 𝑊𝑖

x 100

Where 𝑊𝑖 and 𝑊𝑒 are the weights of the samples before and after extraction, respectively. As expected, no exothermic peaks are observed. This absence of exothermic peaks reveals the total cure of both networks after the full curing program applied to the materials. Furthermore, the 0 % extractible contents found for 60/40 poly(CDGE)/poly(EDBz) corroborate the DSC results.

In conclusion, it can be deduced that the selected curing program is suitable for the elaboration of IPN materials between CDGE and EDBz. The following part focuses on the CDGE/EDBz monomers ratio onto the properties of the final materials. , and ν is the Poisson's ratio of the blend calculated using a combination of mixing, G the shear modulus, and ɸi is the volume fraction of each component polymers.

Unlike the two previous models, Davies reported a model taking into account the interactions between the two polymer phases in which both phases are co-continuous over the whole material. 243 In this particular case, the shear modulus G is expressed as:

𝐺 1/5 = ɸ 1 𝐺 1 1/5 + ɸ 2 𝐺 2 1/5
As a reminder, these three models have rather been developed for the mechanical properties of polymer blends. Nevertheless, numerous authors report their use for the description of IPNs viscoelastic properties. 244,245 These models were shown to give an idea of the materials morphology.

The modulus values calculated from the three aforementioned models, as well as the experimental data of the poly(CDGE)/poly(EDBz) IPN materials, are reported on the The shear moduli of the IPN materials were then compared to the calculated values obtained by the three models.

It is important to notice that the models are employed for materials which display two transitions on their DMA analysis as it is the case for poly(CDGE)/poly(EDBz) IPN with compositions ranging from 50/50 to 20/80. Nevertheless, in the present case, for three IPN compositions with high the poly(CDGE) and poly(EDBz) single network were swollen in water during 15 days at 80 °C. It was not possible to estimate the amount of water uptake from simple weight measurements because the weight of the swollen samples was to low and the uncertainty of the measures were thus to high. In consequence, the swelling behaviour of the materials was determined from the melting enthalpy of water trapped in the material by DSC analysis. The melting point depression study was followed in the present case. The heating of the swollen materials from -50 °C to 20 °C First of all, it is important to notice that depending on the IPN composition, different phase transitions were observed. No endothermic peak is observed on the DSC curve relative to water melting in the single poly(EDBz) network. Indeed, PBz resins are well-known for their very low water uptake. 120 On the contrary, the poly(CDGE) epoxy network was reported to display a high water uptake, as verified by the presence of a bulk-water melting endothermic peak around 0 °C (ΔH = 27.31 J/g). When adding EDBz to the poly(CDGE) network a clear evolution can be observed. A second endothermic peak shifted to around -10 °C is readily observed. The following attribution of the endothermic peaks were hypothetized based on the work related by Wirtz et al.. 247 The transition at higher temperature (around 0 °C) is related to the melting of the bulk water contained in pores or cavities of the materials. The melting endotherm at lower temperature (around -15 to -10 °C) represents the phase transition of the water confined in the poly(CDGE) network, as water can form hydrogen-bonds with hydrophilic groups of such a polymer. 248 It corresponds to a confined water melting endotherm, and seems to be related to the presence of poly(EDBz) network. A fraction of trapped water in close vicinity of polymer chains does not behave as bulk water, propably beacause of reduced water domain's size. It is furthermore important to notice that with increasing amount of poly(EDBz) resin, the enthalpy of the endothermic peak around 0 °C, attributed as the bulk-water melting peak, is varying from ΔH = 27.31 J/g (poly(EDBz) = 0 wt %) to ΔH = 0.22 J/g (poly(EDBz) = 40 wt %). In addition, the enthalpy of the endothermic peak around -10 °C is also decreasing with increasing amount of poly(EDBz). A threshold is reached at 40 wt % of poly(EDBz). Indeed, melting enthalpy at -10°C related to confined-water becomes higher then that the melting enthalpy of bulk-water at 0°C. IPN water uptake allows probing the IPN hydrophobicity since above 40 wt % of poly(EDBz) in the IPN almost no bulk-water domains are anymore detected and the absorbed water molecules are confined with the polymer chain and decreases gradually as the amount of poly(EDBz) within the IPN increases. As a result, the global water uptake of the IPN materials is deacreasing with increasing amount of EDBz.

In conclusion, the introduction of poly(EDBz) network within the poly(CDGE) network reduces the water uptake of poly(CDGE) with increasing amount of poly(EDBz), while improving their thermo-mechanical properties. Furthermore, an unexpected behaviour was also observed. Indeed, PBz networks are known to have very low water uptake, but it seems that by the elaboration of IPNs with the poly(CDGE) network, the PBz based IPN could be able to be swollen, which could be an interesting application of these new IPNs. Nevertheless, further characterizations are needed in order to confirm the observed results.

Conclusion

Diglycidyl ether of cardanol (CDGE) is a difunctionnal epoxy molecule that could interestingly and advantageously substitute diglycidyl ether of BPA (BADGE) in applications such as coatings.

Indeed, CDGE has better adhesion properties than BADGE in addition to its non-carcinogenic properties compared to BADGE. However, CDGE suffers from a relatively high swelling in water -In conclusion, it was demonstrated in this chapter that obtained IPN from CDGE and EDBZ is possible through a suitable choice of the diamine hardener and of the curing conditions. Materials with interesting properties were obtained, as their behaviour toward water is highly affected by the poly(EDBz) content. These results were just obtained with a model -simple-benzoxazine monomer to prove the feasibility of the concept. As it was shown in the third chapter, the chemical design of benzoxazine monomers is versatile, and it could be easily envisioned that other molecular architecture could be built by using other Bz monomers. Clearly, asymmetric monomers with a cardanol moiety could be a major tool to tailor the morphology and properties of the resulting IPN.

General Conclusion and Perspectives

As mentioned all along the manuscript, the development of polymeric materials from natural and renewable resources has attracted tremendous concern. Among the large variety of biomassderived compounds, cardanol through its inherent properties, has attracted our attention.

Throughout this thesis we have studied the potential of using cardanol as versatile chemical platform to conduct different chemical transformation with the aim to find high add-value applications for this underutilized product. We particularly focused in all our studies on the control of the materials properties by the tuning of their chemical structures.

The first study described in this manuscript was the development of three cardanol-based ammonium surfactants, and their potential as oraganomodifier for clays to enhance the dispersion in composite materials. A particular focus was given to the reactivity of these surfactants toward Monmorillonite clay (MMT) and epoxy resin. Three surfactants bearing different amine reactive functionalities were obtained. The organomodification by cationic exchange of MMT layers was effective using the three cardanol-based surfactants as evidenced by XRD and MALDI-TOF/MS analyses. The increased interlayer distances between the clay platelets were however found to be roughly similar due to the close chemical structure of the surfactants. After the exfoliation, the content of amine functionality availlable (able to further react with epoxy groups) of each surfactant was verified by grafting of furfuryl glycidyl ether and further quantified by MALDI-TOF/MS analysis. Clay mineral-based polymer (CPN) with conventional diglycidyl ether of bisphenol A were then prepared with the three O-MMT. As expected, The XRD analysis and SEM observations coupled with energy dispersive X-ray analyses revealed that the surfactant reactivity towards epoxies influences the clay dispersion. Indeed, for the clay modified by the surfactants with lower available amine functionalities, only an intercalated structure could be evidenced. Oppositely, the exfoliation of the clay layers was clearly favoured by the clay modified by the surfactant displaying the higher content of amine functionality as no diffraction peak could be observed on the corresponding XRD diffractogram.

In the chapter 3 we highlighted in a first stage the synthesis and characterization of PBz materials from bio-based di-Bz monomers. Yet, the potential of PBz material from di-vanillin Bz monomer was very limited because of its early thermal degradation (before melting) and its high melting temperature. In the case of di-cardanol Bz monomer, the corresponding material is an easily processable thermoplastic material that was poorly crosslinked and started creeping around 100 °C. In order to obtain an easily processable bio-based Bz monomer and with the aim to combine the good thermal properties of vanillin-based Bzs and the low melting temperature of the cardanol-based Bz monomer, we reported an efficient preparation of asymmetric bio-based dibenzoxazines (named Vani-Card) via a two-steps synthesis pathway including a controlled monosubstitution of cardanol-based benzoxazines followed by a coupling with vanillin. Such combination resulted in a bio-based Bz monomer displaying a large processing window and high thermal stability (Above polymerization temperature). The reactivity of this monomer was also clearly enhanced in comparison to di-cardanol monomer as highlighted by rheology analyses. Indepth characterization of the thermoset material resulting from asymmetric Vani-Card Bz displayed very comparable thermal and mechanical properties to other known PBzs either partially or fully based on renewable compounds. Finally the presence of the cardanol moiety was shown to strongly improve the thermal stability of the PBz material as evidenced by TGA analysis. This versatile approach is thus a powerful tool to access a wide range of asymmetric bio-based benzoxazines given the large number of precursors available and their possible combination. It paves the way toward easily processable high performance bio-based benzoxazines.

Finally, in the last chapter, we studied the macromolecular reinforcement of a diglycidyl ether of cardanol (CDGE) based network. To this end, a poly(CDGE) network was combined through the formation of interpenetrating polymer networks (IPNs) with a polybenzoxazine network (poly(EDBz)). Since benzoxazine monomers are able to react not only with epoxies but also with their diamine hardeners, an appropriate scrutiny of reactant systems and optimal curing conditions was done. The elaboration of an poly(CDGE)/poly(EDBz) IPN structure was found to be favoured by an in-situ sequential IPN synthesis. The first poly(CDGE) network can be synthetized in a first curing step by polymerization of CDGE with isophorone diamine as hardener at low temperature without interactions with the EDBz monomers present in the system. The second poly(EDBz) network can then be synthetized by homopolymerization of the EDBz monomers at higher temperatures. The properties of the poly(CDGE)/poly(EDBz) materials were then studied in function of their compositions. As expected, DMA characterization highlighted an increase of Tg and elastic moduli of the materials while increasing content of EDBz. The IPN materials morphology was estimated by comparison to experimental models based on the evolution of the storage moduli of the materials as a function of their composition. Our experimental findings fit at very high accordance to the Davies model, tending to a co-continuous system. Nevertheless, in spite of numerous attempts (atomic force microscopy, scanning electron microscopy), it was not possible to observe these morphologies and up to now the viability of this model is not confirmed. Finally, it was observed by swelling testing that the incorporation of poly(EDBz) leads to a significant drop of the swelling of poly(CDGE) in water. In conclusion, the feasibility of the concept of the elaboration of IPN from CDGE and EDBZ in order to reinforce the poly(CDGE) network was achieved in this work.

In conclusion the various studies described in this manuscript highlighted the possibility of using cardanol as a bio-based and very versatile building block for the elaboration of diverse materials including bio-based thermoset materials (polybenzoxazines and epoxies), but also as a component for the elaboration of composite materials. Indeed, in chapter II cardanol-based biobased surfactants were used to elaborate clay-epoxy nanocomposite materials. We could conceive of applying this strategy for the reinforcement of bio-based polybenzoxazine materials for example. Moreover, as described in the chapter III, we managed to elaborate a cardanol-and vanillin-based polybenzoxazine material displaying good properties. In order to further enhance those properties, we could elaborate bio-based polybenzoxazine-clay nanocomposite materials using cardanol-based surfactants as clay organomodifiers. Nevertheless, the high performances of PBz materials were strongly related to the formation of an H-bond network. In order to study the interaction between pristine clay and PBz resins, prior to clay organomodification, we proposed to study the supramolecular interactions between kaolin and poly(EDBz). 149 The thermal and thermo-mechanical properties of the benzoxazine resins were significantly improved.

Finally, in chapter IV we described the improvement of the cardanol-based epoxy network (poly(CDGE)) by the formation of IPN materials with poly(EDBz). Still, in order to improve the properties of poly(CDGE), one can envision for example to tune the structural features of the biobased Bz varying the substituting groups. Indeed, the various functionalities on the bio-based phenolic compounds would allow tailoring the PBz materials properties, as evidence by the effect of the aldehyde function on vanillin for example. In consequence, it could be conceived to further improve the poly(CDGE) material properties by various PBz resins bearing various functional groups. To this aim, the strategy of synthetizing assymetric bio-based Bz monomers from different bio-based phenolic compounds reported in chapter III could be considered.

XRD analysis

Wide-angle X-ray scattering (WAXS) experiments were conducted by means of an X'Pert Pro MPD diffractometer from PANalytical, with a copper Kα radiation (1.54 Å) generated at 45 kV and 40 mA in transmission mode. Scans were recorded from 1.5 ° to 30 °, step size 0.02 ° at 5 °/min scanning rate.

SEM analyis

Scanning electron microscopy (SEM) analyses were performed using a QUANTA FEG 200 from FEI in the low vacuum mode (with water vapor as chamber gas). Chemical contrast analyses were performed with a Gaseous Analytical Detector (GDA) for low magnitude observations. Topographic micrographs were recorded with a secondary electron detector (SE), the chemical contrast micrographs with a backscattered electron detector (BSE) and local elemental analysis performed by Energy dispersive X-ray spectroscopy (EDS). Samples were prepared by cryogenic fracture. The excess of amine was removed by one solvent extraction with NaOH in water (50 mg/L). The organic phase was dried using K2CO3 and evaporated. Viscous orange oil was obtained. 1 H NMR (CDCl3,400 MHz,298 K): δ (ppm) (s, assignment, experimental integration, theoretical integration). δ = 0.91 (m, CH3 from alkyl chain, exp 1. 8 H, th 1.7 H), 1.31 (m, -CH2 from alkyl chain, exp 13.5 H, th 13.6 H), 1.59 (t, -CH2-Ar, exp 2.3 H, th 2 H), 2.04 (m, -CH2*=CH-, exp 3.4 H, th 3.1 H), 2.28-2.95 (m, -CH2-from amine moiety and =CH-CH2*-CH= from Cardanol, exp 15.6 H, th 16.1 H), 3.04 (s, -NH2, exp 4.3 H, th 4 H), 3.84-4.23 (m, H α oxygen atoms, exp 3.5 H, th 3 H), 4.93-5.90 (m,-CH= from alkyl chain, exp 4.8 H, th 4.5 H), 6.68-7.21 (m, H-Ar, exp 4 H, th 4 H).

Synthesis and purification of CardS2

Synthesis of CardS2 is similar to the CardS1 synthesis. 10 g (28 mmol) NC-513 in 100 mL CHCl3 were added to 5 g (84 mmol) of EDA in 20 mL CHCl3. The excess amine was removed by two solvent extractions in brine. The organic phase was dried over K2CO3 and evaporated. Viscous yellow oil was obtained. 1 H NMR (CDCl3,400 MHz,298 K): δ (ppm) (s, assignment, experimental integration, theoretical integration). δ = 0.91 (m, CH3 from alkyl chain, exp 1. 8 H, th 1.7 H) 3.18 (s, -NH2, exp 2.5 H, th 2H), 3.86-4.30 (m, H α oxygen atoms, exp 3.4 H, th 3 H), 4.90-5.93 (m,-CH= from alkyl chain, exp 4.7 H, th 4.5 H), 6.64-7.25 (m, H-Ar, exp 4 H, th 4 H).

Synthesis and purification of CardS3

The synthesis of CardS3 was performed as the previous ones by adding 10 g (28 mmol) NC-513 in 100 mL CHCl3 to 7.40 g (84 mmol) of DMEDA in 20 mL CHCl3. After reaction completion the solvent was evaporated, and crude CardS3 was dissolved in ethyl acetate. Two extractions in brine were carried out, and the organic phase was dried with K2CO3, filtered and evaporated.

Viscous yellow oil was obtained. 1 H NMR (CDCl3,400 MHz,298 K): δ (ppm) (s, assignment, experimental integration, theoretical integration). δ = 0.91 (m, CH3 from alkyl chain, exp 1.8 H, th 1.7 H), 1.32 (m, -CH2 from alkyl chain, exp 13.5 H, th 13.6 H), 1.61 (t, -CH2-Ar, exp 2.2 H, th 2 H), 2.04 (m, -CH2*=CH-, exp 3.6 H, th 3.1 H), 2.47-2.93 (m, -CH2-from amine moiety and =CH-CH2*-CH= from Cardanol, exp 13.6 H, th 14.1 H), 3.86-4.30 (m, H α oxygen atoms, exp 3.4 H, th 3 H), 4.90-5.93 (m,-CH= from alkyl chain, exp 4.9 H, th 4.5 H), 6.64-7.25 (m, H-Ar, exp 4 H, th 4 H). 2.2 Characterization methods 2.2.1 NMR analysis 1 H NMR spectra were performed on a Brucker Avance 400 spectrometer equipped with a 9.4 T Ascent magnet, operating at a proton frequency of 400 MHz. Monomers were dissolved in deuterated chloroform with all peaks referenced relative to tetramethylsilane (TMS). In regard to the integration of the NMR signals, the precise integration depends obviously on the composition of cardanol and related proportion of different isomers. The integrations are usually calculated by moderation based on the abundance of unsaturation described in the literature. 11,51,[204][205][206] These unsaturation abundances can slightly vary regarding the origin and the processing of raw Cardanol extracted from CNSL. As such the integration may diverge from sample to other.

The unsaturations abundances of the used cardanol were considered as follow in our calculations: tri-unsaturated (n=3) ~ 41%, di-unsaturated (n=2) ~ 23%, mono-saturated (n=1) ~ 34%, saturated (n=0) ~ 3%. In addition, the difference of relaxation times between aromatic and aliphatic hydrogen may complicate the accurate quantification of all protons. Therefore, the peaks related to the aliphatic chain of cardanol were integrated to the aliphatic hydrogen in β position of the cardanol aromatic ring, which should integrate for 2H whereas the peak from -OCH3 function on the vanillin compound that should integrate for 3H, was used as reference for all other peaks including those related to the benzoxazine structure.

Mass analysis

Molecular characterizations were also performed by high-resolution mass spectrometry (HR-MS), using a LTQ/Orbitrap Elite (Thermo Scientific) equipped with an atmospheric-pressure matrix-assisted laser desorption/ionization source (AP-MALDI PDF+, Masstech). This analytical setup allows for the investigation of MALDI-produced ions using accurate mass measurement (sub-ppm relative error) and structural confirmation by MSn. Samples were submitted to a solvent-free preparation. α-Cyano-4-hydroxycinnamic acid (CHCA) was used for the analysis of the benzoxazine monomers, and used as received from Sigma-Aldrich (St Louis, MO).

DSC analysis

Differential scanning calorimetry (DSC) thermograms were recorded by means of a Netzsch DSC 204 F1 Phoenix apparatus operating at inert atmosphere (nitrogen) with a linear heating ramp from 20 to 250 °C at 20 °C/min rate. Thermo-gravimetric analysis (TGA) was performed on a Netzsch TG 409 PC Luxx device operating in synthetic air (nitrogen: 80 mL/min and oxygen: 20 mL/min) with heating ramp from ambient temperature to 250 °C. cardanol, exp 1.07, 1.06, 1.00 H, th 1.00, 1.00, 1.00 H), 7.12-7.34 (H-Ar from vanillin, exp 1.00, 1.01 H, th 1.00, 1.00 H), 9.81 ((C=O)H, exp 1.01 H, th 1.00 H).

Material elaboration

Monomers (di-cardanol or Vani-Card) were degased during 1 h above melting temperature (50 and 105 °C, respectively) and then transferred to a U-shaped mold. A curing program of 1 h at 160 °C was applied followed by 2 h at 180 °C and the samples were post-cured for 2 h at 200 °C and 30 min at 220 °C. The evolutions of the melting enthalpies of water were recorded on the swollen samples with the following heating program at inert atmosphere (nitrogen): cooling from ambient temperature to -50 °C at a rate of 20 °C/min, 5 min isotherm at -50 °C followed by a heating to 40 °C at a 5 °C/min heating rate.

Solvent extraction

The solvents extractions of the materials at various curing steps were achieved by CHCl3 extractions in a Soxhlet for 72 h. After extraction the samples were dried under vacuum and then weighed and characterized by DSC analysis.

DMA analysis

Dynamic mechanical analyses (DMA) were carried out on bar samples (5x10x0.5 mm 3 ) with a Q800 model (TA instruments) operating in tension mode with strain at 0.05 %; pretension, 10 -2 N) at 1 Hz with a heating rate of 3 °C/min from ambient temperature to 250 °C.

Material elaboration

The reference materials from EDBz and CDGE, as well as the IPN materials with various compositions, were elaborated by first mixing the CDGE pre-polymer and the EDBz compound at 100 °C and degasing during 1 h at 100 °C, followed by the addition of the IPD hardener in stoichiometric ratio to the CDGE monomer (The stoichiometric amount of hardener was determined by calculation with the equivalent epoxy weight EEW). The mixtures were then transferred to a U-shaped mold. The previously determined curing program of 16 h at 100 °C, 1 h at 160 °C, 2 h at 180 °C, 2 h at 200 °C and 30 min at 220 °C was applied to each material.

Figure 1 .

 1 Figure 1. Global production capacities of bioplastics (In 2013 and forecast for 2018). 2 ...............

Figure I - 1 .

 1 Figure I -1. Main cashew nut producing countries in 2012. ......................................................................

Figure I - 2 .

 2 Figure I -2. Representation of cashew apples. ................................................................................................

Figure I - 3 .

 3 Figure I -3. Cross section of a cashew nut and nutshell. .............................................................................

Figure I - 4 .

 4 Figure I -4. Chemical structure of CNSL components a) anacardic acid, b) cardanol, c) cardol and d) 2-methylcardol. ................................................................................................................................................

Figure I - 5 .

 5 Figure I -5. Anacardic acid decarboxylation. ...................................................................................................

Figure I - 6 .

 6 Figure I -6. Average compositions of the cardanol alkyl side chain. ......................................................

Figure I - 7 .

 7 Figure I -7. Representation of the possible chemical modifications on the three reactive sites of cardanol. ............................................................................................................................................................................

Figure I - 8 .

 8 Figure I -8. Fine chemicals and functional molecules from cardanol. ...................................................

Figure I - 9 .

 9 Figure I -9. Schematic representation of polymer matrix a) plasticizer-free and b) in presence of a plasticizer. ................................................................................................................................................................

Figure I - 10 .

 10 Figure I -10. Chemical structure of mono-epoxidized cardanol NC-513 from Cardolite. .............

Figure I - 11 .

 11 Figure I -11. Chemical structures of cardanol polyepoxy derivatives plasticizers. 18 .....................

Figure I - 12 .

 12 Figure I -12. Schematic representation of the various types of surfactants a) cationic, b) anionic, c) non-ionic and d) zwitterionic. ............................................................................................................

Figure I - 13 .

 13 Figure I -13. Synthesis of cardanol sulfonate surfactants. 30 ......................................................................

Figure I - 14 .

 14 Figure I -14. Synthesis of cardanol diazonium sulfonate surfactant. 44 .................................................

Figure I - 15 .

 15 Figure I -15. Chemical structure of cardanol carbonate surfactant. 45 ...................................................

Figure I - 16 .

 16 Figure I -16. Chemical structure of sulfonated acrylate cardanol surfactants a) sulfonated-3pentadecyl phenyl acrylate and b) sodium-2-acryloxy ethan-1-oxy(3-pentedecyl) benzene sulfonate. 47 .......................................................................................................................................................................

Figure I - 17 .

 17 Figure I -17. Chemical structure of cardanol polyethoxylate surfactants. 27, 48 ..................................

Figure I - 18 .

 18 Figure I -18. Chemical structure of cardanol quaternary ammonium salt surfactants. 49 .............

Figure I - 19 .

 19 Figure I -19. Synthesis of cardanol ammonium salt surfactants. 51 .........................................................

Figure I - 20 .

 20 Figure I -20. Synthesis of cardanol phenalkamine curing agent. 52 .........................................................

Figure I - 21 .

 21 Figure I -21. Chemical structure of phenalkamine component from a) hexamethylenediamine and b) diethylenetriamine. 55 .....................................................................................................................................

Figure I - 22 .

 22 Figure I -22. Synthesis of phenalkamine compounds from cardanol with varying molecular weight and amine content. 56 .....................................................................................................................................

Figure I - 23 . 16 Figure I - 24 .

 231624 Figure I -23. Synthesis of cardanol-based phenalkamine compound by thiol-ene chemistry. 16Figure I -24. Chemical structures of a) cardanol-cysteamine, and b) commercial NX-5454 phenalkamine. .................................................................................................................................................................

Figure I - 25 .

 25 Figure I -25. Chemical structures of cardanol-based antioxidants. .......................................................

Figure I - 26 .

 26 Figure I -26. Synthesis of cardanol-based phenolic resin. 63 ......................................................................

Figure I - 27 .

 27 Figure I -27. Condensation of cardanol with furfural and para-hydroxyacetophenone. 66 ...........

Figure I - 28 .

 28 Figure I -28. Synthesis of a polyurethane. ........................................................................................................

Figure I - 29 .

 29 Figure I -29. Chemical structures of cardanol-based diols a) 72 b) 73 c) 69 . .............................................

Figure I - 30 .

 30 Figure I -30. Synthesis of cardanol-based polyol by reaction with oxazolidine. 74 ...........................

Figure I - 31 .

 31 Figure I -31. Synthesis of cardanol-based polyols by reaction with melamine and diethanolamine. 75 ..............................................................................................................................................................

Figure I - 32 .

 32 Figure I -32. Synthesis of cardanol-based polyols by reaction with epichlorohydrin and diethanol amine or with glycerol monochlorohydrin. 73 ................................................................................

Figure I - 33 .

 33 Figure I -33. Synthesis of cardanol-based polyols by performic acid oxidation. 76 ..........................

Figure I - 34 .

 34 Figure I -34. Synthesis of cardano-based polyols by thiol-ene coupling with 2mercaptoethanol. 77 .......................................................................................................................................................

Figure I - 35 .

 35 Figure I -35. Synthesis of CNSL-based urethane polyols via a non-isocyanate route. 78 ................

Figure I - 36 .

 36 Figure I -36. Chemical structure of diglycidyl ether of cardanol -commercially available NC514 -from Cardolite Corporation. ...................................................................................................................................

Figure I - 37 .

 37 Figure I -37. Proposed reaction between epoxy groups of cardanol and carboxyl-terminated polybutadiene. 22 .............................................................................................................................................................

Figure I - 38 .

 38 Figure I -38. Synthesis of epoxidized cardanol pre-polymer. 25 ...............................................................

Figure I - 39 .

 39 Figure I -39. Synthesis of epoxidized cardanol and polycardanol. 80 ....................................................

Figure I - 40 .

 40 Figure I -40. Synthesis of a benzoxazine monomer. 81 ..................................................................................

Figure II - 1 .

 1 Figure II -1. Schematic representation of a) MMT multi-scale organization, 93 and b) MMT crystallographic structure. 89 .....................................................................................................................................

Figure II - 2 .

 2 Figure II -2. Schematic representation of a) phase separated microcomposites, b) intercalated nanocomposites, and c) exfoliated nanocomposites. .....................................................................................

Figure II - 3 .

 3 Figure II -3. Schematic representation of the monomer inclusion within MMT, followed by insitu polymerization to reach MMT exfoliation. .................................................................................................

Figure II - 4

 4 Figure II -4 Grafting of an amino-silane compound on prior organomodified MMT clay. 108 .......

Figure II - 5 .

 5 Figure II -5. Chemical structure of cardanol-based quaternary ammonium surfactant from De Avellar et al. 49 ..................................................................................................................................................................

Figure II - 6 .

 6 Figure II -6. Synthesis of cardanol-based ammonium surfactant from the cardanol mono-epoxy derivative NC-513. 51 .....................................................................................................................................................

Figure II - 7 .

 7 Figure II -7. Scanning Electron Micrographs of BADGE/DAC polymer network filled with a) 5 wt% neat sepiolite and b) 5 wt% sepiolite organomodified by PkH + . 51 .................................................

Figure II - 8 .

 8 Figure II -8. Schematic representation of the synthesis of the Cardanol-based surfactants. ......

Figure II - 9 .

 9 Figure II -9. FTIR spectra of a) CardS1, b) CardS2, c) CardS3...................................................................

Figure II - 10 .

 10 Figure II -10. CardS1 1 H NMR spectrum (Solvent CDCl3). ..........................................................................

Figure II - 11 .

 11 Figure II -11. CardS2 1 H NMR spectrum (Solvent CDCl3). ..........................................................................

Figure II - 12 .

 12 Figure II -12. CardS3 1 H NMR spectrum (Solvent CDCl3). ..........................................................................

Figure II - 13 .

 13 Figure II -13. MALDI-MS spectra of CardS1 using a) CHCA & b) DCTB as matrix, CardS2 using c) CHCA & d) DCTB and CardS3 using e) CHCA & f) DCTB as matrix. ...........................................................

Figure II - 14 .

 14 Figure II -14. Proposed mechanism for DCTB adduction to an aliphatic primary amine. 113 .......

Figure II - 15 .

 15 Figure II -15. X-Ray diffractograms of pristine MMT and O-MMT..........................................................

Figure II - 16 .

 16 Figure II -16. MALDI-MS spectra, using DCTB-Ag as matrix, of a) CardS1-MMT, b) CardS2-MMT, and c) CardS3-MMT. .....................................................................................................................................................

Figure II - 17 .

 17 Figure II -17. Chemical structure of furfuryl glycidyl ether (Fge). .........................................................

Figure II - 18 .

 18 Figure II -18. Reaction between epoxy and primary and secondary amine functions. .................

Figure II - 19 .

 19 Figure II -19. MALDI-MS spectra of Fge-grafted a) CardS1-MMT, b) CardS2-MMT, and c) CardS3-MMT using DCTB-Ag as matrix. ...............................................................................................................

Figure II - 20 .

 20 Figure II -20. X-ray diffractograms of CPN prepared with 10 mass% of pristine and organomodified MMT by CardS1, CardS2 and CardS3. ..................................................................................

Figure II - 21 .

 21 Figure II -21. DSC thermograms of BADGE/DAC and CPN prepared with 5, 7, and 10 wt% of pristine MMT. ..................................................................................................................................................................

Figure II - 22 .

 22 Figure II -22. DSC thermograms of BADGE/DAC and CPN prepared with 5, 7, and 10 wt% of MMT modified by CardS1. ..........................................................................................................................................

Figure II - 23 .

 23 Figure II -23. I) Scanning electron micrographs of the fracture of MMT-CardS3 (above part) and MMT-CardS1 (bottom part) based CPN. a) corresponds to the topographic micrographs, b) to the chemical contrast (BSE detector, the lightest the points and the heaviest the elements) and c) is the aluminium distribution of the analysed area ...........................................................................

Figure III - 1 .

 1 Figure III -1. Classical two-step approach for the synthesis of mono-benzoxazine monomers. 120 ...............................................................................................................................................................................................

Figure III - 2 .

 2 Figure III -2. Chemical structure of a) mono-benzoxazine (m-Bz) and b) di-benzoxazine (di-Bz) monomers. ........................................................................................................................................................................

Figure III - 3 .

 3 Figure III -3. Thermally-induced ring opening polymerization of Bz monomers. 120 ......................

Figure III - 4 .Figure III - 5 .

 45 Figure III -4. Dimer product of para-substituted m-Bz monomer via ring-opening reaction. 124 Figure III -5. Possible polymerization reactions sites in order the most to the least predominant: 1 ortho, 2 para, 3 meta. 120 .............................................................................................................

Figure III - 6 .

 6 Figure III -6. Chemical structures of the Bz monomers used for the elaboration of Bz/CNT nanocomposites. 143 -M1: Bisphenol A/aniline based Bz monomer and M2: 1,4-phenylene diamine/phenol based Bz monomer. ....................................................................................................................

Figure III - 7 .

 7 Figure III -7. Representative SEM images of a) pristine kaolin and b) 10 wt% kaolin/EDBz. ....

Figure III - 8 .

 8 Figure III -8. Chemical structure and thermal properties of Bz monomers containing carboxylic groups. 158 ..........................................................................................................................................................................

Figure III - 9 .

 9 Figure III -9. Chemical structures of Class A and Class B di-Bz monomers. .......................................

Figure III - 10 .

 10 Figure III -10. Chemical structure of Class B di-Bz monomer. .................................................................

Figure III - 11 .

 11 Figure III -11. Synthesis of di-Bz monomers bearing maleimide functional groups. 167 ...............

Figure III - 12 .

 12 Figure III -12. Example of naturally occurring phenolic derivatives used for the synthesis of bio-based Bz monomers. ..........................................................................................................................................

Figure III - 13 .

 13 Figure III -13. Schematization of the participation of the aldehyde group in the ring opening polymerization of the para hydroxyl benzaldehyde Bz monomers. 182 .................................................

Figure III - 14 .

 14 Figure III -14. Crosslinking of vanillin-based di-Bz monomers. 181 .......................................................

Figure III - 15 .

 15 Figure III -15. Chemical structure of lignin-derivative compounds: coumaric acid (CA), ferulic acid (FE), and phloretic acid (PA). ........................................................................................................................

Figure III - 16 .

 16 Figure III -16. Available positions for ring opening polymerization of eugenol-based Bz monomer. ........................................................................................................................................................................

Figure III - 17 .

 17 Figure III -17. Elaboration of crosslinked materials from eugenol-based Bz monomers by copolymerization between allyl group and bismaleimides. 187 .................................................................

Figure III - 18 .

 18 Figure III -18. Chemical structures of a) umbeliferone and b) 4-methylumbeliferone coumarin compounds. ....................................................................................................................................................................

Figure III - 19 .

 19 Figure III -19. Chemical structure of urushiol. .............................................................................................

Figure III - 20 .

 20 Figure III -20. Available positions for ring opening polymerization of urushiol-based Bz monomer. ........................................................................................................................................................................

Figure III - 21 .

 21 Figure III -21. Synthesis di-Bz asymmetric monomer by reaction between aminophenol and hydrobenzaldehyde and butylamine (u-butyl-Bz) or hexylamine (u-hexyl-Bz). 201 .........................

Figure III - 22 .

 22 Figure III -22. Synthesis of blends of di-eugenol, di-cardanol and asymmetric eugenol/cardanol di Bz monomers. 202 ....................................................................................................................................................

Figure III - 23 .

 23 Figure III -23. Synthesis of symmetric Bz monomers from various phenolic compounds like phenol, vanillin or cardanol. ...................................................................................................................................

Figure III - 24 . 1 H

 241 Figure III -24. 1 H NMR spectrum (in CDCl3) of di-phenol benzoxazine monomer. .......................

Figure III - 25 . 1 H

 251 Figure III -25. 1 H NMR spectrum (in CDCl3) of di-vanillin benzoxazine monomer. ......................

Figure III - 26 . 1 H

 261 Figure III -26. 1 H NMR spectrum (in CDCl3) of di-cardanol benzoxazine monomer. ....................

Figure III - 27 .

 27 Figure III -27. MALDI-TOF/MS spectrum of di-phenol benzoxazine monomer. ............................

Figure III - 28 .

 28 Figure III -28. HRMS spectrum of di-vanillin benzoxazine monomer. ...............................................

Figure III - 29 .

 29 Figure III -29. HRMS analysis of di-vanillin Bz monomer a) Zoom of the experimental product peaks b) Theoretical mass of the expected product. ....................................................................................

Figure III - 30 .

 30 Figure III -30. HRMS spectrum of di-cardanol benzoxazine monomer. .............................................

Figure III - 31 .

 31 Figure III -31. HRMS analysis of di-cardanol Bz monomer a) Zoom of the experimental product peaks b) Theoretical mass of the expected product. ....................................................................................

Figure III - 32 .

 32 Figure III -32. MS/MS analysis of di-cardanol Bz monomer. ..................................................................

Figure III - 33 .

 33 Figure III -33. DSC (N2, 20 k/min) and TGA (N2, 20 k/min) analyses of di-phenol monomer. .

Figure III - 34 .

 34 Figure III -34. DSC (N2, 20 k/min) and TGA (N2, 20 k/min) analyses of di-vanillin Bz monomer. .............................................................................................................................................................................................

Figure III - 35 .

 35 Figure III -35. DSC (N2, 20 k/min) and TGA (N2, 20 k/min) analyses of the di-cardanol benzoxazine monomer. .............................................................................................................................................

Figure III - 36 .

 36 Figure III -36. Isothermal rheology monitoring of di-phenol Bz monomer at 190 °C -empty markers: storage modulus G'; filled markers: loss modulus G''. ..............................................................

Figure III - 37 .

 37 Figure III -37. Isothermal rheology monitoring of di-cardanol Bz monomer at 190 °C -empty markers: storage modulus G'; filled markers: loss modulus G''. ..............................................................

Figure III - 38 .

 38 Figure III -38. Synthesis of the asymmetric Vani-Card Bz monomer from cardanol and vanillin. .............................................................................................................................................................................................

Figure III - 39 . 1 H

 391 Figure III -39. 1 H NMR spectrum (in CDCl3) of Vani-Card benzoxazine monomer. .......................

Figure III - 40 .

 40 Figure III -40. HRMS analysis of Vani-Card Bz monomer a) Zoom of the experimental product peaks b) Theoretical mass of the expected product. ....................................................................................

Figure III - 41 .

 41 Figure III -41. HRMS spectrum of Vani-Card benzoxazine monomer. ................................................

Figure III - 42 .

 42 Figure III -42. DSC thermograms (N2, 20 K/min) of a) di-vanillin, b) Vani-Card Bz monomers and c) di-cardanol Bz monomer. ...........................................................................................................................

Figure III - 43 .

 43 Figure III -43. DSC (N2, 20 k/min) and TGA (N2, 20 k/min) analyses of the Vani-Card Bz monomer. ........................................................................................................................................................................

Figure III - 44 .

 44 Figure III -44. Isothermal rheology monitoring of Vani-Card (circular markers) and di-cardanol (triangular markers) benzoxazines at 190°C -empty markers: storage modulus G'; filled markers: loss modulus G''. .......................................................................................................................................

Figure III - 45 .

 45 Figure III -45. DMA thermograms of poly(di-cardanol), poly(di-phenol) and poly(Vani-Card). .............................................................................................................................................................................................

Figure III - 46 .

 46 Figure III -46. TGA (air atmosphere, 20K/min) thermograms of a) di-cardanol, b) di-phenol and c) Vani-Card PBz materials. ............................................................................................................................

Figure IV - 1 .

 1 Figure IV -1. Chemical structure of diglycidyl ether of cardanol (CDGE) -commercially available NC514 -from Cardolite Corporation................................................................................................

Figure IV - 2 .

 2 Figure IV -2. Friedel-Crafts alkylation of phenol with cardanol (ideal reaction pathway). .......

Figure IV - 3 .

 3 Figure IV -3. Chemical structure of diglycidyl ether of cardanol determined by 1 H NMR analysis. 213 ......................................................................................................................................................................

Figure IV - 4 .

 4 Figure IV -4. Chemical structure of CDGE obtained from NMR and SEC analysis. 213 ....................

Figure IV - 5 .

 5 Figure IV -5. Additional chemical compounds composing CDGE determined by MALDI-MS analysis a) epoxidized cardanol bearing an additional phenol moiety, b) epoxidized cardanol containing both an epoxidated and a native phenol on its side chain, c) epoxidized cardanol linked to a native cardanol, d) two epoxidized cardanol linked by a native phenol. 204 .................

Figure IV - 6 .

 6 Figure IV -6. CDGE cross-linking agents a) isophorone diamine and b) Jeffamine D400. ..........

Figure IV - 7 .

 7 Figure IV -7. Chemical structure of 1,2-diaminocyclohexane (DAC) cross-linking agent. ..........

Figure IV - 8 .

 8 Figure IV -8. Synthesis of Pbz/epoxy co-networks. 217 ...............................................................................

Figure IV - 9 .

 9 Figure IV -9. Reaction between epoxy and primary and secondary amine functions. .................

Figure IV - 10 .

 10 Figure IV -10. Reaction scheme of opening the oxazine ring via an amine nucleophilic attack. 229 .............................................................................................................................................................................................

Figure IV - 11 .

 11 Figure IV -11. Sequential synthesis of IPN. ....................................................................................................

Figure IV - 12 .

 12 Figure IV -12. In-situ IPN synthesis. ..................................................................................................................

Figure IV - 13 .

 13 Figure IV -13. Nucleation and growth mechanism. ....................................................................................

Figure IV - 14 .

 14 Figure IV -14. Gyroïdal structure. ......................................................................................................................

Figure IV - 15 .

 15 Figure IV -15. a) Expected reactions during the IPN sequential in-situ synthesis, b) in-situ sequential synthesis of a poly(CDGE)/poly(Bz) IPN material. .................................................................

Figure IV - 16 .

 16 Figure IV -16. Chemical structure of the EDBz model Bz monomer. ...................................................

Figure IV - 17 .

 17 Figure IV -17. Curing conditions of CDGE with various diamine compounds monitored by DSC analysis (N2, 20 K/min), compared to the curing conditions of the EDBz monomer (Dashed curve, (N2, 20 K/min)). ..............................................................................................................................................

Figure IV - 18 .

 18 Figure IV -18. Curing conditions of various systems a) CDGE with IPD, b) EDBz and c) 60/40 CDGE/EDBz with IPD monitored by DSC analysis (N2, 20 K/min). ........................................................

Figure IV - 19 .

 19 Figure IV -19. Curing conditions of CDGE/EDBz (60/40 % wt) systems. .........................................

Figure IV - 20 .

 20 Figure IV -20. DSC analysis (N2, 20 K/min) of the poly(CDGE) material (without EDBz) after the first curing step of 16 h at 100 °C. ........................................................................................................................

Figure IV - 21 .

 21 Figure IV -21. DSC analysis (N2, 20 K/min) of the poly(CDGE)/EDBz (60/40) system after the first curing step of 16 h at 100 °C, and compared to neat poly(CDGE) after 16 h at 100 °C. .......

Figure IV - 22 .

 22 Figure IV -22. DSC analysis (N2, 20 K/min) of the poly(CDGE)/poly(EDBz) (60/40) material after the full curing program (1 h at 160 °C, 2h at 180 °C, 2h at 200 °C and 30 min at 220 °C).

  NMR peaks of the di-phenol benzoxazine monomer and their theoretical and experimental integrations. ........................................................................................... Table III -14. Assignments of the 1 H NMR peaks of the di-vanillin benzoxazine monomer and their theoretical and experimental integrations. ...........................................................................................

Figure 1 .

 1 Figure 1. Global production capacities of bioplastics (In 2013 and forecast for 2018).2

1Figure I - 1 .

 1 Figure I -1. Main cashew nut producing countries in 2012.

Figure I - 2 .- 3 ) 5 Figure I - 3 .

 2353 Figure I -2. Representation of cashew apples.

Figure I - 4 .

 4 Figure I -4. Chemical structure of CNSL components a) anacardic acid, b) cardanol, c) cardol and d) 2-methylcardol.

Figure I - 5 .

 5 Figure I -5. Anacardic acid decarboxylation.

  Cardanol was thus found to display an average of 1.5 unsaturations, with a majority of triunsaturated compound (40-50%), followed by the mono-unsaturated compound (30-35%), the di-unsaturated compound (15-20%), and very few saturated compound (1-4%) (FigureI -6).

Figure I - 6 .

 6 Figure I -6. Average compositions of the cardanol alkyl side chain.

Figure I - 7 .

 7 Figure I -7. Representation of the possible chemical modifications on the three reactive sites of cardanol.

  chapter. In the study described in the Chapter II, we took advantage of the amphiphilic chemical structure of cardanol to synthetize ammonium surfactant by reaction on the phenolic hydroxyl function (Figure I -8a). The synthesis of cardanol-based benzoxazine monomers highlighted in Chapter III occurred also by reaction on the cardanol hydroxyl group, coupled to a reaction on the aromatic ring on cardanol (Figure I -8b). Finally the synthesis of a cardanol diglycidyl ether compound studied in the Chapter IV resulted from modification on both hydroxyl phenolic group and alkyl side chain unsaturations of cardanol (Figure I -8c).

Figure I - 8 .

 8 Figure I -8. Fine chemicals and functional molecules from cardanol.

  and processability. A plasticizing compound is usually a low molecular weight molecule with both suitable polar and non-polar entities. Indeed a plasticizer molecule is able to penetrate within a polymeric matrix through hydrophobic compatibility and to establish polar attractive forces with the polymeric matrix chains reducing thus the cohesive forces between the polymer chains (Figure I -9).

Figure I - 9 .

 9 Figure I -9. Schematic representation of polymer matrix a) plasticizer-free and b) in presence of a plasticizer.

  Trade mark NC-513 (Cardolite) (Figure I -10).42

Figure I - 10 .

 10 Figure I -10. Chemical structure of mono-epoxidized cardanol NC-513 from Cardolite.

Figure I - 11 .

 11 Figure I -11. Chemical structures of cardanol polyepoxy derivatives plasticizers. 18

  Surfactants are classified into four classes based on the nature of the hydrophilic group (Figure I -12).

Figure I - 12 .

 12 Figure I -12. Schematic representation of the various types of surfactants a) cationic, b) anionic, c) non-ionic and d) zwitterionic.

Figure I - 13 .

 13 Figure I -13. Synthesis of cardanol sulfonate surfactants. 30

Figure I - 14 .

 14 Figure I -14. Synthesis of cardanol diazonium sulfonate surfactant.[START_REF] Anilkumar | [END_REF]

Figure I - 15 .

 15 Figure I -15. Chemical structure of cardanol carbonate surfactant.45

47 Figure I - 16 .

 4716 Figure I -16. Chemical structure of sulfonated acrylate cardanol surfactants a) sulfonated-3pentadecyl phenyl acrylate and b) sodium-2-acryloxy ethan-1-oxy(3-pentedecyl) benzenesulfonate.47

Figure I - 17 .

 17 Figure I -17. Chemical structure of cardanol polyethoxylate surfactants.27,48

  end of the aliphatic chain of cardanol aiming at enhancing the lipophilic character of the surfactant (Figure I -18).

Figure I - 18 .

 18 Figure I -18. Chemical structure of cardanol quaternary ammonium salt surfactants.49

Figure I - 19 .

 19 Figure I -19. Synthesis of cardanol ammonium salt surfactants. 51

Figure I - 20 .

 20 Figure I -20. Synthesis of cardanol phenalkamine curing agent. 52

Figure I - 21 .

 21 Figure I -21. Chemical structure of phenalkamine component from a) hexamethylenediamine and b) diethylenetriamine.55

Figure I - 22 .

 22 Figure I -22. Synthesis of phenalkamine compounds from cardanol with varying molecular weight and amine content.56

  (cardanol cysteamine) by thiol-ene chemistry (Figure I -23) and the elaboration of a fully bio-based epoxy thermoset material.

Figure I - 23 .

 23 Figure I -23. Synthesis of cardanol-based phenalkamine compound by thiol-ene chemistry.16

Figure I - 24 .

 24 Figure I -24. Chemical structures of a) cardanol-cysteamine, and b) commercial NX-5454 phenalkamine.

Figure I - 25 .

 25 Figure I -25. Chemical structures of cardanol-based antioxidants.

4. 1

 1 Phenolic resinsOne of the most considered applications of cardanol is its use as phenolic precursor for novolac or resole type resin. Indeed, cardanol can undergo condensation with formaldehyde at ortho or para position of the phenolic ring to form cardanol-formaldehyde (CF) resins (Figure I -26).63

Figure I - 26 .

 26 Figure I -26. Synthesis of cardanol-based phenolic resin. 63

Figure I - 27 .

 27 Figure I -27. Condensation of cardanol with furfural and para-hydroxyacetophenone. 66

Figure I - 28 .

 28 Figure I -28. Synthesis of a polyurethane.

Figure I - 29 .

 29 Figure I -29. Chemical structures of cardanol-based diols a) 72 b) 73 c) 69 .

Figure I - 30 .

 30 Figure I -30. Synthesis of cardanol-based polyol by reaction with oxazolidine.74

Figure I - 31 .

 31 Figure I -31. Synthesis of cardanol-based polyols by reaction with melamine and diethanolamine.75

Figure I - 32 .

 32 Figure I -32. Synthesis of cardanol-based polyols by reaction with epichlorohydrin and diethanol amine or with glycerol monochlorohydrin.73

Figure I - 33 .

 33 Figure I -33. Synthesis of cardanol-based polyols by performic acid oxidation.76

Figure I - 34 . 34 .

 3434 Figure I -34. Synthesis of cardano-based polyols by thiol-ene coupling with 2mercaptoethanol.77

Figure I - 35 .

 35 Figure I -35. Synthesis of CNSL-based urethane polyols via a non-isocyanate route.78

Figure I - 36 . 22 Figure I - 37 .

 362237 Figure I -36. Chemical structure of diglycidyl ether of cardanol -commercially available NC514 -from Cardolite Corporation.

Figure I - 38 .

 38 Figure I -38. Synthesis of epoxidized cardanol pre-polymer. 25

Figure I - 39 .

 39 Figure I -39. Synthesis of epoxidized cardanol and polycardanol. 80

4. 4

 4 Polybenzoxazine resinsPolybenzoxazine (PBz) resins are another class of high performance thermoset materials. They are emerging since three decades, and due to their outstanding properties and to their monocomponent resin status, they are considered as promising substitutes to phenolic or epoxy resins.Polybenzoxazine resins are obtained through the ring-opening polymerization of benzoxazine (Bz) monomers. The synthesis of benzoxazine monomers is based on a Mannich-like reaction between a phenolic compound and formaldehyde, followed by a ring-closure process on a phenolic derivative (Figure I -40).81

Figure I - 40 .

 40 Figure I -40. Synthesis of a benzoxazine monomer. 81

79

 79

1. 2

 2 Structure and properties of clay and layered silicates as fillers Clay and lamellar silicates, especially the smectite type -2:1 clay minerals -are widely available and the most commonly used as natural fillers. More particularly, MMT clays have several assets which justify their wide use: a high cation exchange capacity (CEC, meq/100g), a multiscale organization (Figure II -1a), good swelling properties in water and a large surface area. 91, 92 The distinctive structure of MMT clay consists in platelets each composed of two tetrahedral silica sheets -SiO4-framing an octahedral alumina sheet -Al(OH)3-(Figure II -1b), separated by metallic cations.

Figure II - 1 .

 1 Figure II -1. Schematic representation of a) MMT multi-scale organization, 93 and b) MMT crystallographic structure.89

Figure II - 2 .

 2 Figure II -2. Schematic representation of a) phase separated microcomposites, b) intercalated nanocomposites, and c) exfoliated nanocomposites.

  initiated and the limited polymer network (outside the clay interlayer) remains sufficiently mobile to facilitate further migration of the monomers into the clay interlayer galleries for further exfoliation. In the case of epoxy as polymeric matrix, a correlation has been found between the surfactant Lewis acidity and a catalytic growth of the epoxy network, favouring the clay mineral layers separation (exfoliation) in the following order: CH3(CH2)17NH3 + > CH3(CH2)17N(CH3)H2 + > CH3(CH2)17N(CH3)2H + > CH3(CH2)17N(CH3)3 + .105, 106 Primary ammonium surfactants are thus favouring the clay exfoliation within an epoxy matrix through acid catalyses, whereas quaternary ammonium surfactants tend to lower hydration and desorption of the surfactants. This correlation highlights the difficulty to select the appropriate type of surfactant.

Figure II - 3 .

 3 Figure II -3. Schematic representation of the monomer inclusion within MMT, followed by insitu polymerization to reach MMT exfoliation.

Le

  Pluart et al. proposed the modification of MMT clay by combination of cationic exchange and covalent grafting reactions. 108 The MMT clay interlayer space and hydrophobic property were modified by the introduction by cationic exchange reaction of dimethylbenzylammonium surfactants. The MMT clay was then further modified by the grafting of amino-silane compounds -reactive towards epoxy polymers-onto the hydroxyl groups situated on the surfaces and edges of the MMT clay platelets (Figure II -4).

Figure II - 4

 4 Figure II -4 Grafting of an amino-silane compound on prior organomodified MMT clay. 108

Figure II - 5 .

 5 Figure II -5. Chemical structure of cardanol-based quaternary ammonium surfactant from De Avellar et al.49

Figure II - 6 .

 6 Figure II -6. Synthesis of cardanol-based ammonium surfactant from the cardanol mono-epoxy derivative NC-513. 51

Figure II - 7 .

 7 Figure II -7. Scanning Electron Micrographs of BADGE/DAC polymer network filled with a) 5 wt% neat sepiolite and b) 5 wt% sepiolite organomodified by PkH + . 51

2. 1

 1 Surfactants synthesisAs described in the previous part, keeping an amino-multifunctionnality is essential to promote the clay oragnomodification in a first time, and the polymer growth within the clay platelets in a second time. Primary and secondary amine groups available within the surfactant would allow the grafting of epoxy compounds within the organomodified clay, improving thus the polymer intercalation and growth within the clay. This first part, focused on the amino-multifunctionnality of cardanol-based surfactants, specially tailored to highlight the surfactant reactivity-to-clay exfoliation relationship. Three surfactants were prepared from an epoxy derivative of cardanol (NC-513) with amino compounds of different amine functionalities toward epoxies.The same conditions were applied to synthetize each surfactant (FigureII -8). The cardanolbased surfactants were synthetized through nucleophilic addition of a primary amine on the epoxide group of NC-513 in chloroform. The amine was added in excess to the media in order to favour the mono-addition of cardanol on the amine compound. Indeed, it is preferred to keep the maximum of reactive (free) primary and secondary amine functions on the surfactant so that they may be able to react once they are incorporated to the clay. Depending on the amine functionality, cardanol-based surfactants CardS1, CardS2 and CardS3 were synthesized.Tris(2-aminoethyl)amine (TAEA) was used as reagent for the synthesis of the CardS1 surfactant with a functionality of 5 (f = 5) (because two free primary -NH2 functions accounting for 4 and one secondary -NH function are available, accounting for 1). The use of ethylene diamine (EDA) allowed the synthesis of the CardS2 surfactant with a functionality of 3 (f = 3) (one free -NH2 and one free -NH functions). Finally, the CardS3 surfactant with a functionality of 1 (f = 1) was synthetized with N,N-dimethylethylenediamine (DMEDA) (one free -NH function). The synthesis and the chemical structures of the surfactants are displayed on Figure II -8. towards epoxy, were thus synthetized: CardS1 (f = 5) > CardS2 (f = 3) > CardS3 (f = 1).

Figure II - 8 .

 8 Figure II -8. Schematic representation of the synthesis of the Cardanol-based surfactants.

  Nevertheless, cardanol-based products are composed of four molecules differing by the unsaturation degree of their alkyl chains. These unsaturation abundances can slightly vary regarding the origin and the processing of the CNSL based bio-product for the manufacturing of NC-513. The assignments depicted in Figure II -10

  Iexp and Ith respectively. The NMR spectrum of CardS1 is displayed in Figure II -10.

Figure II - 10 .

 10 Figure II -10. CardS1 1 H NMR spectrum (Solvent CDCl3).

  at 7.15 and 6.75 ppm (used as integration reference), the alkyl chain olefinic CH2 protons[b2, d2, e2, g2, h2, a2] at 5.81, 5.35, and 5.03 ppm, the protons in α of the alkyl chain unsaturations [c2, f2, i2] at 2.04 ppm, as well as the CH2 protons in α of the aromatic [o] at 1.59 ppm, the CH2 from the alkyl chain [b1, c1, d1, e1, f1, g1, h1, i1, j, k, l, m, n] at 1.31 ppm and the CH3 of the alkyl chain at 0.91 ppm. The CH2 of the alkyl chain comprised between two unsaturations [c3, f3] were detected at 2.28-2.95 ppm, together with CH2 protons from the used amine moiety. The experimental and theoretical integrations of the CardS1 peaks are reported in the Table

Figure II - 11 .

 11 Figure II -11. CardS2 1 H NMR spectrum (Solvent CDCl3).

Figure II - 13 .

 13 Figure II -13. MALDI-MS spectra of CardS1 using a) CHCA & b) DCTB as matrix, CardS2 using c) CHCA & d) DCTB and CardS3 using e) CHCA & f) DCTB as matrix.

  the surfactant replaces the dicyanomethylene group of DCTB forming a matrix adduct via a -C=Nbond (Figure II -14). As DCTB is not a protic matrix, silver (Ag) was added to the moleculematrix mixture in order to protonate them for their detection.

Figure II - 14 .

 14 Figure II -14. Proposed mechanism for DCTB adduction to an aliphatic primary amine. 113

Figure II - 15

 15 Figure II -15. X-Ray diffractograms of pristine MMT and O-MMT.

Figure II - 16 . 2 . 2 . 3 ;

 16223 Figure II -16. MALDI-MS spectra, using DCTB-Ag as matrix, of a) CardS1-MMT, b) CardS2-MMT, and c) CardS3-MMT.

Figure II - 17 .

 17 Figure II -17. Chemical structure of furfuryl glycidyl ether (Fge).

Figure II - 18 .

 18 Figure II -18. Reaction between epoxy and primary and secondary amine functions.

Figure II - 19 .

 19 Figure II -19. MALDI-MS spectra of Fge-grafted a) CardS1-MMT, b) CardS2-MMT, and c) CardS3-MMT using DCTB-Ag as matrix.

2. 5

 5 Preparation and characterization of CPN materials 2.5.1 CPN preparation procedure Clay mineral-based polymer nanocomposite (CPN) with conventional diglycidyl ether of Bisphenol A (BADGE) were prepared to validate the impact of the available amine functionalities of surfactants onto the MMT exfoliation. It is worthy to remind that the CPN with MMT or O-MMT were prepared thanks to a simple magnetic stirring without any additional dispersion or exfoliation enhancement.Composite materials, composed of BADGE epoxy cured by diaminocyclohexane (DAC) and including 10 wt% of O-MMT organomodified by CardS1, CardS2 or CardS3, were elaborated and their morphology as well as their properties were investigated. A 10 wt% pristine MMT/BADGE composite was also prepared as a reference.2.5.2 CPN characterization by X-ray diffraction (XRD)The effect of the MMT organomodification on the interlayer space between the clay platelets was previously characterized. The interlayer distance was shown to increase from 12.6 Å (pristine MMT) to around 20 Å regardless to the used surfactant.In the following part, the relationship between amino-functionnalities of the surfactant reactive towards epoxy within the clay and their effect on the MMT clay intercalation or exfoliation within the BADGE polymer matrix were studied. To this aim, the composite materials were characterized by XRD analysis. X-ray diffractograms of the CPN are reported on Figure II -20. First of all, it can be noted that a diffraction peak from 2θ = 10 ° to 2θ = 20 °, due to BADGE, was observed in each diffractogram of CPN materials.

Figure II - 20 .

 20 Figure II -20. X-ray diffractograms of CPN prepared with 10 mass% of pristine and organomodified MMT by CardS1, CardS2 and CardS3.

Figure II - 21 .

 21 Figure II -21. DSC thermograms of BADGE/DAC and CPN prepared with 5, 7, and 10 wt% of pristine MMT.

Figure II - 22 .

 22 Figure II -22. DSC thermograms of BADGE/DAC and CPN prepared with 5, 7, and 10 wt% of MMT modified by CardS1.

Figure II - 23

 23 Figure II -23. I) Scanning electron micrographs of the fracture of MMT-CardS3 (above part) and MMT-CardS1 (bottom part) based CPN. a) corresponds to the topographic micrographs, b) to the chemical contrast (BSE detector, the lightest the points and the heaviest the elements) and c) is the aluminium distribution of the analysed area

Figure III - 1 .

 1 Figure III -1. Classical two-step approach for the synthesis of mono-benzoxazine monomers. 120

Figure III - 2 .Figure III - 3 .Figure III - 4 .Figure III - 5 .

 2345 Figure III -2. Chemical structure of a) mono-benzoxazine (m-Bz) and b) di-benzoxazine (di-Bz) monomers.

  Dumas et al. 143 proposed the elaboration of PBz/CNT nanocomposites with good thermo-mechanical properties through the facile and efficient dispersion of neat CNTs within various Bz compounds: M1 (Bisphenol A/aniline based Bz monomer) and M2 (1,4phenylene diamine/phenol based Bz monomer) (Figure III -6).

Figure III - 6 .

 6 Figure III -6. Chemical structures of the Bz monomers used for the elaboration of Bz/CNT nanocomposites. 143 -M1: Bisphenol A/aniline based Bz monomer and M2: 1,4-phenylene diamine/phenol based Bz monomer.

  supramolecular assembly with Bz. Composite materials, containing 10 wt% of neat kaolin, were elaborated. The FTIR measurements attested of the establishment of supramolecular H-bonding interactions between EDBz and kaolin in the monomer melt, leading to fine clay dispersion into the resin after polymerization, as evidenced by SEM analyses (Figure III -7).

Figure III - 7 .

 7 Figure III -7. Representative SEM images of a) pristine kaolin and b) 10 wt% kaolin/EDBz.

  Some researchers studied also the ring opening catalysis of Bz monomers by the addition of catalytic functional groups on the monomers such as carboxylic acids. 157, 158 Andreu et al. 158 analysed the thermal polymerization behaviour of several carboxylic-containing Bz monomers (Figure III -8), and studied their effect on the polymerization temperature when used as comonomer with a (phenol/aniline) monomer (m1). The thermal properties of the different Bz monomers are in Figure III -8.

Figure III - 8 .

 8 Figure III -8. Chemical structure and thermal properties of Bz monomers containing carboxylic groups. 158

1. 1 . 5

 15 Focus on di-benzoxazine monomers Di-functional Bz monomers are favoured for the elaboration of high performance PBz materials. They are divided in two classes, depending on whether they are prepared from a di-phenol (Class A) or a diamine (Class B). These two classes are schematized in Figure III -9.

Figure III - 9 .

 9 Figure III -9. Chemical structures of Class A and Class B di-Bz monomers.

1. 2

 2 Synthesis of Class B benzoxazines The synthesis of class B di-Bz monomers is determined by the nature and origin of each reagent while the synthesis conditions and yields are strongly affected by the electron donating and withdrawing effects as well as by the length of the diamine bridging group (Figure III -10).

Figure III - 10 .

 10 Figure III -10. Chemical structure of Class B di-Bz monomer.

4 . 5 .

 45 of epoxy-based thermoset materials, are largely preferred for the synthesis of high glass transition temperature (Tg) materials. The thermal properties of model aromatic-di-Bz monomers, synthetized from aromatic diamines and phenols, and those of their corresponding PBz materials are listed in Table III -The brittle nature of aromatic PBz materials has led researchers to consider aliphatic diamines as flexible bridging group to design Bz monomers, hereafter known as aliphatic-di-Bz. The thermal properties of model aliphatic-di-Bz monomers, synthetized from various chain length linear diamines and phenol, and their corresponding aliphatic-PBz materials are listed in Table Thermal properties of aliphatic-di-Bz monomers, synthetized from various chain length linear diamines and phenol, and Tg of their corresponding aliphatic-PBz materials.The chain length of flexible linear diamine bridging groups is an essential parameter affecting the thermal properties of the di-Bz monomers and their related PBz materials. The melting temperatures of aliphatic Bz monomers were found to be significantly lower than those of aromatic-di-Bz monomers (< 155 °C), while their polymerization temperatures remained in the usual temperature range of 200-220 °C. Moreover, the melting temperatures of the aliphatic Bz monomers were considerably decreased, from 112 °C to 49 °C, with increasing the diamine bridging group chain length. Thus, the processing windows Tproc of aliphatic di-Bz monomers were wider than for aromatic-di-Bz, from 73 °C to 192 °C with increasing the diamine chain length. Furthermore, the glass transition temperatures (Tg) also decreased proportionally from 179 °C to 105 °C with increasing the diamine chain length.162

  167 A set of di-Bz monomers was synthetized by bridging phenyl maleimides with various diamines using xylene as high boiling point solvent (Figure III -11). The ring-opening polymerization of the phenyl maleimide-based Bz monomers, as well as the addition-polymerization of the maleimide groups occurred in the same temperature range of traditional Bz monomers (Tp ~ 200 °C -220 °C), while the resulting PBz materials exhibited high Tg (c.a. 300 °C) and excellent thermal stability (T5% > 370 °C).

Figure III - 11 .

 11 Figure III -11. Synthesis of di-Bz monomers bearing maleimide functional groups. 167

1. 4

 4 Bio-based benzoxazine: State of the art With the growing trend to produce environmentally-friendly and high performance materials derived from renewable resources, the use of bio-based phenolic derivatives for the synthesis of Bz monomers is considered as a viable alternative to petroleum-based phenolic counterparts. A broad screening of various mono-or di-functional Bz monomers from naturally occurring phenolic compounds, and their resulting materials have been reported during the last years, attesting the clear trend of promoting the use of renewable bio-resourced reagents for the development of competitive bio-based thermosets (Figure III -12).

Figure III - 12 .

 12 Figure III -12. Example of naturally occurring phenolic derivatives used for the synthesis of bio-based Bz monomers.

  Thermal properties of vanillin-based Bz monomers, synthetized from monofunctional amines or diamines, and Tg and T5% of their corresponding PBz materials. It has been shown that the presence of the aldehyde group on vanillin has an immediate effect on the thermal properties of the Bz monomer. Indeed, the presence of the formyl group on the vanillin compound induces the formation of inter-and intra-molecular H bonds. Consequently, in comparison to classical phenol-aniline Bz monomer, the melting temperature of vanillin-aniline Bz monomer (

  6, line 4). These high melting temperatures, really close to the polymerization temperatures are impeding the processing of these monomers (melting and shaping). Nevertheless, vanillin-based Bz monomers led remarkably to cross-linked materials in spite of substituted phenolic ortho and para positions, impeding the polymerization. It turns out that the participation of the aldehyde group in the ring opening polymerization of the Bz monomers has been previously reported.182 However, it was shown that the additional crosslinking reactions, due to the presence of an aldehyde group within a Bz monomer, occur mainly at the ortho position of the phenolic compound (Figure III -13).

Figure III - 13 .Figure III - 14 .

 1314 Figure III -13. Schematization of the participation of the aldehyde group in the ring opening polymerization of the para hydroxyl benzaldehyde Bz monomers. 182

Figure III - 15 .

 15 Figure III -15. Chemical structure of lignin-derivative compounds: coumaric acid (CA), ferulic acid (FE), and phloretic acid (PA).

8 .

 8 ). Bz monomers with relatively high melting temperatures were obtained. Polymerization temperatures of the Bz monomers were strongly affected by the carboxylic acid function. Indeed, the carboxylic acid function acts as a polymerization catalyst, lowering the polymerization temperatures compared to Bz with methylated functions. Thus, similarly to di-vanillin Bz monomers, processing windows of Bz monomers with carboxylic acid function were low, due to high melting temperatures (Tm = 117 °C and 121 °C for CA-Bz, FA-Bz) and low polymerization temperatures (Tp = 137 °C and 130 °C respectively). The use of the methylated coumaric and ferulic compounds allowed an increase of the processing window by increasing the polymerization temperatures (processing windows = 107 °C and 37 °C respectively). Furthermore, low thermal stability was reported for CA-Bz and FA-Bz, as well as for their methylated derivatives CAM-Bz and FAM-Bz. Indeed, except for phloretic acid and methylated phloretic acid based Bz monomers (PA-Bz and PAM-Bz), the polymerization proceeded with partial decomposition, probably due to the presence of the conjugated double bond. This phenomenon also impeded the preparation of suitable materials. Thermal properties of lignin-derivative-based Bz monomers, synthetized from mono-functional amines or diamines, and Tg and T5% of their corresponding PBz materials. 1.4.4 Eugenol Eugenol, through its availability and low cost, has also attracted attention for the synthesis of biobased Bz monomers. Eugenol is the main component (72 to 90 %) in the essential oil obtained from cloves. It can also be extracted from other essential oils such as nutmeg, cinnamon, basil or bay leaf oils. Eugenol chemical structure is a di-substituted phenolic compound by a methoxy and an allyl group at ortho and para positions respectively. Consequently, due to blocked ortho and para positions, only the low reactive meta positions are available, impeding the formation of a cross-linked eugenol-based network (Figure III -16).

Figure III - 16 . 9 .

 169 Figure III -16. Available positions for ring opening polymerization of eugenol-based Bz monomer.

Figure III - 18 . 10 . 11 .

 181011 Figure III -18. Chemical structures of a) umbeliferone and b) 4-methylumbeliferone coumarin compounds.

  Ambrozic and al. proposed to increase the functionality of the Bz monomer through the reaction between cardanol and furfurylamine (TableIII -11, line 5).194 The furanic ring of furfurylamine is highly reactive and promotes thus an increase of the crosslinking density.197 Indeed, when comparing cardanol-based mono-functional Bz monomers to other amine derivatives, such as aniline or benzylamine (Tg = 58 °C and 52.8 °C respectively) (TableIII -11, line 2 and 4,respectively) for example, a distinct shift of the Tg to higher temperatures (Tg = 100 °C), was observed for the furfurylamine-based PBz material. Very interestingly, the use of furfurylamine accessed to the formation of a self-supported material, which could be analysed by DMA.Consequently, cardanol-based Bz monomers displayed wide processing windows owing to their low melting temperatures due to the steric hindrance brought by the C15 alkyl chain. However, the low crosslinking density and Tg of the corresponding PBz materials, as well as the high polymerization temperatures, are major drawbacks for the elaboration of high performance thermosets from cardanol with good thermo-mechanical properties.1.4.7 UrushiolUrushiol is another naturally occurring phenolic compound, extracted from lacquer trees. Its chemical structure is very close to those of cardanol as it is a 3-substituted catechol derivative with a C15 alkyl chain in meta position. Like for the cardanol compound, the unsaturation degrees of the alkyl chain, from unsaturated to tri-saturated, and their abundances are varying (FigureIII -19).

Figure III - 19 .

 19 Figure III -19. Chemical structure of urushiol.

Figure III - 20 . 12 .

 2012 Figure III -20. Available positions for ring opening polymerization of urushiol-based Bz monomer.

Figure III - 21 .

 21 Figure III -21. Synthesis di-Bz asymmetric monomer by reaction between aminophenol and hydrobenzaldehyde and butylamine (u-butyl-Bz) or hexylamine (u-hexyl-Bz). 201

Figure III - 22 .

 22 Figure III -22. Synthesis of blends of di-eugenol, di-cardanol and asymmetric eugenol/cardanol di Bz monomers. 202

2. 1 1 (

 11 Symmetric benzoxazine monomers synthesis and characterization 2.1.1 Symmetric Bz monomer synthesis In a first time, symmetric benzoxazine monomers from phenol, vanillin or cardanol (coined hereafter di-phenol, di-vanillin and di-cardanol) were synthetized by reacting together phenol or vanillin or cardanol, paraformaldehyde and ethylene diamine (EDA) is stoichiometric ratio 2:4:Figure III -23).

Figure III - 23 .

 23 Figure III -23. Synthesis of symmetric Bz monomers from various phenolic compounds like phenol, vanillin or cardanol.

2. 1 . 2

 12 Characterization by 1 H NMR -Di-phenol benzoxazine monomer The 1 H NMR spectrum corresponding to the di-phenol Bz monomer is depicted in Figure III -24.

Figure III - 24 . 1 H

 241 Figure III -24. 1 H NMR spectrum (in CDCl3) of di-phenol benzoxazine monomer.

15 )

 15 indicating the probable presence of two cardanol moieties within the monomer. This was further confirmed by the integration of the following peaks from cardanol , the alkyl chain olefinic CH2 protons[b2, d2, e2, g2, h2, a2] at δ = 4.96 -5.88 ppm, the protons in α of the alkyl chain unsaturations [c2, f2, i2] at δ = 1.98 -2.09 ppm, as well as the CH2 protons in α of the aromatic [o] at δ = 2.49 -2.57 ppm, the CH2 from the alkyl chain[b1, c1, d1, e1, f1, g1, h1, i1, j, k, l, m, n] at δ = 1.23 -1.43 ppm and the CH3 of the alkyl chain [a1] at δ = 0.86 -0.94 ppm. The CH2 of the alkyl chain comprised between two unsaturations [c3, f3] were detected at δ = 2.76-2.87 ppm. The experimental and theoretical integrations of the di-cardanol Bz compound peaks are reported in the Table III -15. As it can be observed, the experimental integrations of the peaks corresponding to the cardanol moiety are 123 close to the expected integrations for the di-cardanol Bz monomer containing two cardanol moieties.

3

 3 Characterization by MALDI-TOF/MS or HRMS The chemical structure of the di-phenol symmetric Bz monomer were confirmed by MALDI-TOF/MS characterisation, and by High Resolution Mass Spectrometry (HRMS) characterisation for the di-vanillin and di-cardanol monomers. -Di-phenol benzoxazine monomer The chemical structure of the synthetized reference di-phenol Bz monomer was characterized by MALDI-TOF/MS. The corresponding spectrum is displayed in Figure III -27.

Figure III - 27 .Figure III - 28 .

 2728 Figure III -27. MALDI-TOF/MS spectrum of di-phenol benzoxazine monomer.

Figure III - 29 .

 29 Figure III -29. HRMS analysis of di-vanillin Bz monomer a) Zoom of the experimental product peaks b) Theoretical mass of the expected product.

Figure III - 30 .

 30 Figure III -30. HRMS spectrum of di-cardanol benzoxazine monomer.

Figure III - 31 .

 31 Figure III -31. HRMS analysis of di-cardanol Bz monomer a) Zoom of the experimental product peaks b) Theoretical mass of the expected product.

Figure III - 32 .

 32 Figure III -32. MS/MS analysis of di-cardanol Bz monomer.

  Figure III -33. The DSC analysis revealed a moderate processing window of the di-phenol monomer with Tm = 115 °C and Tp = 212 °C. The processing of this monomer to a polybenzoxazine material is thus relatively easy.

Figure III - 33 .

 33 Figure III -33. DSC (N2, 20 k/min) and TGA (N2, 20 k/min) analyses of di-phenol monomer.

Figure III - 34 .

 34 Figure III -34. DSC (N2, 20 k/min) and TGA (N2, 20 k/min) analyses of di-vanillin Bz monomer.

Figure III - 35 .

 35 Figure III -35. DSC (N2, 20 k/min) and TGA (N2, 20 k/min) analyses of the di-cardanol benzoxazine monomer.

Figure III - 36 .

 36 Figure III -36. Isothermal rheology monitoring of di-phenol Bz monomer at 190 °C -empty markers: storage modulus G'; filled markers: loss modulus G''.

Figure III - 37 .

 37 Figure III -37. Isothermal rheology monitoring of di-cardanol Bz monomer at 190 °C -empty markers: storage modulus G'; filled markers: loss modulus G''.

2. 2

 2 Asymmetric benzoxazine monomers synthesis and characterization 2.2.1 Asymmetric Bz monomer synthesis Accordingly, with an appropriate adjustment of the reagents stoichiometry, asymmetric benzoxazine monomers were synthetized (cardanol, EDA, paraformaldehyde reacted in CHCl3 at 70 °C under reflux in stoichiometric ratio 1:1:2), mono-substituted cardanol-benzoxazine was obtained. To produce the so-called Vani-Card asymmetric Bz monomer, vanillin was added in a second step to the precedent reaction crude with paraformaldehyde in stoichiometric ratio 1:2 and reacted at 70 °C (Figure III -38).

Figure III - 38 .

 38 Figure III -38. Synthesis of the asymmetric Vani-Card Bz monomer from cardanol and vanillin.

Figure III - 39 . 1 H

 391 Figure III -39. 1 H NMR spectrum (in CDCl3) of Vani-Card benzoxazine monomer.

23 - 1 .

 231 16) indicatingprobably the presence of only one cardanol moiety within the monomer. This was further corroborated by the integration of the remaining peaks from cardanol, the alkyl chain olefinic CH2 protons[b2, d2, e2, g2, h2, a2] at δ = 4.96 -5.88 ppm, the protons in α of the alkyl chain unsaturations [c2, f2, i2] at δ = 1.98 -2.09 ppm, as well as the CH2 protons in α of the aromatic[o] at δ = 2.49 -2.57 ppm, the CH2 from the alkyl chain [b1, c1, d1, e1, f1, g1, h1, i1, j, k, l, m, n] at δ = 1.43 ppm and the CH3 of the alkyl chain [a1] at δ = 0.86 -0.94 ppm. The CH2 of the alkyl chain comprised between two unsaturations [c3, f3] were detected at δ = 2.76-2.87 ppm. The experimental and theoretical integrations of the peaks corresponding to the cardanol moiety of the Vani-Card monomer are reported in the TableIII-16 with the aliphatic hydrogen in β position of the cardanol aromatic ring, as integration reference (I = 2 H). As it can be observed, the experimental integrations of the peaks corresponding to the cardanol moiety are close to the expected integrations for Vani-Card Bz monomer containing one cardanol moiety.

2. 2 . 3

 23 Characterization by MALDI-TOF/MS The asymmetric Bz monomer was also successfully detected by mass analysis (Figure III -40a) as the protonated Vani-Card specie was observed at m/z 559, as well as the expected ions [M+H+H2O-CH2O] + at m/z 547 and [M-H+H2O-CH2O] + at m/z = 545. The theoretical expected mass of Vani-Card is displayed on Figure III -40b. The mass found for the asymmetric monomer m/z 559.3531 is very close to the theoretical mass expected of m/z 559.3530, confirming the formation of the expected Vani-Card monomer.

Figure III - 40 .

 40 Figure III -40. HRMS analysis of Vani-Card Bz monomer a) Zoom of the experimental product peaks b) Theoretical mass of the expected product.

Figure III - 41 .

 41 Figure III -41. HRMS spectrum of Vani-Card benzoxazine monomer.

Figure III - 42 .

 42 Figure III -42. DSC thermograms (N2, 20 K/min) of a) di-vanillin, b) Vani-Card Bz monomers and c) di-cardanol Bz monomer.

Figure III - 43 . 45 .

 4345 Figure III -43. DSC (N2, 20 k/min) and TGA (N2, 20 k/min) analyses of the Vani-Card Bz monomer.

Figure III - 45 .

 45 Figure III -45. DMA thermograms of poly(di-cardanol), poly(di-phenol) and poly(Vani-Card).

Figure III - 46 . 18 .

 4618 Figure III -46. TGA (air atmosphere, 20K/min) thermograms of a) di-cardanol, b) di-phenol and c) Vani-Card PBz materials.

  is why researchers are focusing on the development of totally or partially bio-based and potential environmentally friendly BPA-free epoxy thermosets. Among the most promising bio-based alternatives, cardanol has attracted a tremendous level of interest within the materials community. In particular, di-glycidyl ether of cardanol (CDGE) (Figure IV -1) could be considered as a viable alternative to traditional thermosets prepared from BADGE.

Figure IV - 1 .

 1 Figure IV -1. Chemical structure of diglycidyl ether of cardanol (CDGE) -commercially available NC514 -from Cardolite Corporation.

Figure IV - 2 .

 2 Figure IV -2. Friedel-Crafts alkylation of phenol with cardanol (ideal reaction pathway).

Figure IV - 3 . 13

 313

Figure IV - 3 .

 3 Figure IV -3. Chemical structure of diglycidyl ether of cardanol determined by 1 H NMR analysis. 213

Figure IV - 4 .

 4 Figure IV -4. Chemical structure of CDGE obtained from NMR analysis. 213

Figure IV - 6 .

 6 Figure IV -6. CDGE cross-linking agents a) isophorone diamine and b) Jeffamine D400.

  as the water resistance were studied for different compositions of BADGE/CDGE co-networks, cross-linked with 1,2-diaminocyclohexane (DAC) (Figure IV -7) in stoichiometric amount.

Figure IV - 7 .

 7 Figure IV -7. Chemical structure of 1,2-diaminocyclohexane (DAC) cross-linking agent.

1. 3

 3 Reinforcement strategies: macromolecular reinforcement of epoxy networksOwing the high performance properties of polybenzoxazines, their use as reinforcement for the cardanol-based epoxy material -CDGE -has been foreseen in the following chapter. Indeed, polybenzoxazines materials are known to have excellent thermo-mechanical properties and high stiffness. Their use as reinforcement of the epoxy network properties appears thus as a promising opportunity. Nevertheless, despite the advantageous properties of polybenzoxazine materials, their high brittleness and low cross-linking density, in comparison to epoxy thermosets for example, are the major drawbacks of polybenzoxazine materials. The particular properties of PBz are explained by the formation of strong H-bonding between the phenolic hydroxyl groups and the tertiary amines of the Mannich linkages formed by ROP.[129][130][131][132] Thus, to date, the majority of the works reported on polybenzoxazine and epoxy resins aimed at the the improvement of the flexibility of benzoxazine resins by co-reactions and co-crosslinking with epoxy resins. 2161.3.1 State of the art of the epoxy/benzoxazine based co-networksIn several recent works, co-networks between epoxy and benzoxazine resins have been reported to successfully improve the thermal and mechanical properties of the resulting material. As benzoxazine monomers are reactive towards amines, but also towards the epoxy groups themselves, various strategies have been considered for the reinforcement of benzoxazines by co-polymerization with epoxy resins. 1.3.1.1 Epoxy/benzoxazine Ishida et al. 217 were first to report the preparation of PBz/epoxy co-networks by the reaction between the epoxy groups and the phenolic hydroxyl group issued from the opening of the oxazine ring (Figure IV -8). In this work, BADGE was reacted with a bisphenol-A based benzoxazine in weight proportion 30/70. An increase of the Tg (from 141 °C to 156 °C) was observed due to the additional cross-linking density added by the benzoxazine molecules.

Figure IV - 8 .

 8 Figure IV -8. Synthesis of Pbz/epoxy co-networks. 217

  Benzoxazine monomers were shown to react with epoxy groups after their ring opening (Figure IV -8). In particular, benzoxazine monomers are reactive towards primary amines (Figure IV -10) used to crosslink epoxy networks. Such a reaction occurring at low temperature, would lead to a competition with the epoxy/amine cross-linking reaction (Figure IV -9).

Figure IV - 9 .

 9 Figure IV -9. Reaction between epoxy and primary and secondary amine functions.

Figure IV - 11 .

 11 Figure IV -11. Sequential synthesis of IPN.

Figure IV - 12 .

 12 Figure IV -12. In-situ IPN synthesis.

Figure IV - 13 .Figure IV - 14 .

 1314 Figure IV -13. Nucleation and growth mechanism.

2. 1

 1 Figure IV -15. a) Expected reactions during the IPN sequential in-situ synthesis, b) in-situ sequential synthesis of a poly(CDGE)/poly(Bz) IPN material.

2. 1 . 2

 12 Determination of the Bz monomer As described previously, it is essential to control the competition reactions which may occur between benzoxazines, epoxy and amine compounds in order to elaborate IPNs. For this reason, the suitable conditions for the elaboration of IPN between CDGE and benzoxazines are studied in the following chapter. A benzoxazine model molecule synthetized from phenol, ethylenediamine and paraformaldehyde, (EDBz, Figure IV -16) has been selected in order to avoid any likely additional side-reaction from benzoxazines substituents or functional groups.

Figure IV - 16 .

 16 Figure IV -16. Chemical structure of the EDBz model Bz monomer.

Figure IV - 18 .

 18 Figure IV -18. Curing conditions of various systems a) CDGE with IPD, b) EDBz and c) 60/40 CDGE/EDBz with IPD monitored by DSC analysis (N2, 20 K/min).

2. 2 . 1

 21 First step curing 2.2.1.1 Evaluation of the poly(CDGE) formation The DSC of the poly(CDGE) reference material, without EDBz, after the first cure of 16 h at 100 °C, is displayed in Figure IV -20.

Figure IV - 20 .

 20 Figure IV -20. DSC analysis (N2, 20 K/min) of the poly(CDGE) material (without EDBz) after the first curing step of 16 h at 100 °C.

Figure IV - 22 .

 22 Figure IV -22. DSC analysis (N2, 20 K/min) of the poly(CDGE)/poly(EDBz) (60/40) material after the full curing program (1 h at 160 °C, 2 h at 180 °C, 2 h at 200 °C and 30 min at 220 °C).

2. 3 . 2

 32 Thermo-mechanical properties of IPN materials The thermo-mechanical properties of poly(CDGE)/poly(EDBz) IPNs were studied by DMA analysis and displayed on Figure IV -23. For the sake of comparison, the two single networks poly(EDBz) and poly(CDGE) were also elaborated using the same curing conditions and characterized by DMA.

Figure IV - 23 .

 23 Figure IV -23. Evolution of the storage modulus E' of poly(CDGE)/poly(EDBz) IPNs (80/20, 70/30, 60/40, 50/50, 40/60, 30/70 and 20/80) as a function of temperature, obtained by DMA (Tension mode with 0.05 % strain, 1 Hz and 3 °C/min).

Figure IV - 25 .

 25 Figure IV -25. Evolution of the tanδ of poly(CDGE)/poly(EDBz) IPNs (50/50, 40/60, 30/70 and 20/80) as a function of temperature, obtained by DMA (tension mode with 0.05% strain, 1Hz and 3°C/min).

Figure IV - 26 .

 26 The models and materials modulus are reported versus their EDBz volume content. The shear moduli (G') of the poly(CDGE)/poly(EDBz) IPN materials were determined by the E' and tanδ data measured by DMA analysis as follow:As models assume mixing of a hard and a soft polymer, the values of E' and tanδ were taken at 140°C (poly(CDGE) in elastic state and poly(EDBz) in glassy state). In consequence, the Poisson's coefficients of rubbery poly(CDGE) and glassy poly(EDBz) networks are equal to 0.50 and 0.33 respectively. The Poisson coefficient of the IPN materials is calculated as the volume average of those of the both component, depending their composition by the following formula: 𝜈 = ((0.50 * 𝐶𝐷𝐺𝐸 𝑣/𝑣%) + (0.33 * 𝐸𝐷𝐵𝑧 𝑣/𝑣%))

  at 5 k/min was observed. The DSC curves during heating of the water swollen IPN materials and single networks are displayed in Figure IV -27.

Figure IV - 27 .

 27 Figure IV -27. DSC thermograms of poly(CDGE)/poly(EDBz) IPNs (80/20, 70/30, 60/40, 50/50, 40/60, 30/70 and 20/80) and poly(CDGE) and poly(EDBz), during the heating of swollen materials (N2, 5 K/min).

1. 2 . 5

 25 DSC analysis Differential scanning calorimetry (DSC) thermograms were recorded by means of a Netzsch DSC 204 F1 Phoenix apparatus operating at inert atmosphere (nitrogen) with a linear heating ramp from 20 to 250 °C at 20 °C/min rate. 1.3 Surfactant synthesis 1.3.1 Synthesis and purification of CardS1Typically 5 g (14 mmol) of NC-513 in 100 mL CHCl3 were added to 6 g (41 mmol) of TAEA in 10 mL CHCl3. The mixture was heated at reflux for 20 h; the consumption of NC-513 was followed by TLC, indicating reaction completion.

  MALDI-MS. CHCA Matrix: Detected m/z, Elemental Composition, Assignment. m/z 501.42/503.43/505.45, C30H53/55/57N4O2 + , [M (n=3/2/1) + H] + .

  MALDI-MS. CHCA Matrix: Detected m/z, Elemental Composition, Assignment. m/z 443.36/445.38/447.39, C28H47/49/51N2O2 + , [M (n=3/2/1) + H] + .

  MALDI-MS. CHCA Matrix: Detected m/z, Elemental Composition, Assignment. m/z 415.33/417.35/419.36, C26H43/45/47N2O2 + , [M (n=3/2/1) + H] + . 1.4 MMT clay organomodification Standard cation exchange procedures were employed for the preparation of organomodified MMT (O-MMT). Typical procedure it used to modify 1 g of clay consist in dissolving 1.12 g of CardS1 (2 equivalents to MMT's CEC) in 50 mL of EtOH at 80 °C. 20 mL of HCl solution in EtOH (0.1 M) were added to protonate CardS1 to CardS1H+. The resulting solution was then added to the MMT/water dispersion (100 mL water for 1 g of MMT) and the final mixture heated to 80 °C. The cation exchange reaction was maintained for 16 hours at 80 °C under intensive magnetic stirring. The O-MMT was filtrated and washed with 80 °C heated ethanol/water solution (50/50), until no traces of Cl-could be detected with AgNO3. O-MMT are noted CardS1-MMT, CardS2-MMT and CardS3-MMT. 1.5 Reaction of the intercalated surfactants with Fge Furfuryl glycidyl ether (Fge) was used to evidence the residual reactivity of the surfactants intercalated in O-MMT. Two drops of Fge were added to the dispersed O-MMT in CH2Cl2. The mixtures were maintained under magnetic stirring for 8 hours at room temperature, and were then filtered and dried at room temperature. The characterization of Fge-grafted surfactants was done by MALDI-TOF/MS analysis. 1.6 Clay mineral-based polymer nanocomposite (CPN) preparation 10 mass% Clay/BADGE were prepared by mixing BADGE to O-MMT at 80 °C under vacuum during 1 hour. 1 epoxy-equivalent of DAC (1,2-diaminocyclohexane as the amine hardener) was then added. The mixture was immediately transferred in a high-temperature silicone mold. The thermal treatment was 2 h at 160 °C, followed by a post-cure at 190 °C during 2 h. The resulting materials were characterized by X-ray diffraction and scanning electron microscopy. 2 Chapter III: Benzoxazines from cardanol 2.1 Materials Cardanol (Ultralite 2023) was supplied by Cardolite. Ethylenediamine, paraformaldehyde, vanillin, and the solvents were all purchased from Aldrich and used as received without any purification.

3

  Chapter IV: Interpenetrating Polymers Networks (IPN) from cardanol-based thermoset networks 3.1 Materials CDGE (Commercial name NC-514) was supplied by Cardolite (EEW = 490 g/eq). 1,2diaminocyclohexane (mixture of isomers) was purchased from Sigma-Aldrich and used as received. The EDBz benzoxazine monomer was synthetized and purified as described in the Chapter III.

3. 2

 2 Characterization methods 3.2.1 DSC analysis Differential scanning calorimetry (DSC) thermograms were recorded by means of a Netzsch DSC 204 F1 Phoenix apparatus operating at inert atmosphere (nitrogen) with a linear heating ramp from 20 to 250 °C at 20 °C/min rate for the analyses of the curing of the monomers.

  Figure IV -23. Evolution of the storage modulus E' of poly(CDGE)/poly(EDBz) IPNs(80/20, 70/30, 60/40, 50/50, 40/60, 30/70 and 20/80) as a function of temperature, obtained by DMA (Tension mode with 0.05 % strain, 1 Hz and 3 °C/min). ............................................................................ Evolution of the storage modulus E' and tanδ of poly(CDGE)/poly(EDBz) IPNs (80/20, 70/30 and 60/40) as a function of temperature, obtained by DMA (tension mode with 0.05% strain, 1Hz and 3°C/min). .......................................................................................................................... ). ................................................................................................................................................................ Shear modulus of poly(CDGE)/poly(EDBz) IPN materials versus EDBz volume fraction compared with modulus-composition models. .............................................................................

	Figure IV -24. Figure IV -25. Evolution of the tanδ of poly(CDGE)/poly(EDBz) IPNs (50/50, 40/60, 30/70 and
	20/80) as a function of temperature, obtained by DMA (tension mode with 0.05% strain, 1Hz
	and 3°C/minFigure IV -26.

Figure IV -27. DSC thermograms of poly(CDGE)/poly(EDBz) IPNs (80/20, 70/30, 60/40, 50/50, 40/60, 30/70 and 20/80) and poly(CDGE) and poly(EDBz), during the heating of swollen materials (N2, 5 K/min). ..........................................................................................................................

Table I - 1 .

 I1 Composition of the phenolic components in natural and technical CNSL. 11 .................

Table I - 2 .

 I2 Composition of the abundances of the constituents of cardanol by various techniques. 10 ....................................................................................................................................................................

Table I - 3 .

 I3 Percentage retention of the physical properties after ageing of the PVC compounds dioctyl phthalate (DOP), Cl-cardanol, Cl-cardanol acetate, Cl-cardanol methyl ether. 39 .................

Table I - 4 .

 I4 Physico-chemical properties of the reactive surfactants compared to the properties of standard non-reactive sodium dodecyl sulfonate anionic surfactant. ...............................................

Table I - 5 .

 I5 Isolated product yields (%) of phase transfer catalysed reactions. 49 .............................. Properties of phenalkamines synthetized from cardanol, formaldehyde and isophorone diamine. 56 .................................................................................................................................................

	Table I -6.

Table I -7. DTA measurements describing antioxidants effects of various antioxidants in MLO under air atmosphere. 59 (Ti: initial thermal degradation temperature, Tmax: degradation temperature.) .................................................................................................................................................................. Table I -8. DTA measurements describing antioxidants effects of various antioxidants in MLO under air atmosphere. 60

(Ti: initial thermal degradation temperature, Tmax: degradation temperature.) .................................................................................................................................................................. Table I -9. Inhibition rate constants (kinh) obtained by studying the AIBN initiated autoxidation of styrene at 30 °C in homogeneous solution using chlorobenzene (PhCl) as a solvent, or in a two-phases water/styrene system. 62 .................................................................................................................... Table I -10. Thermal of CAP1 and CAP2 based PU materials. 77 (T10% is the temperature at 10 wt% weight loss and Tmax is the temperature at maximum rate weight loss). ....................................

Table II -

 II

1. Example of fillers for the elaboration of nanocomposites. 83 ............................................. Table II -2. CardS1 experimental and theoretical integrations. ............................................................... Table II -3. CardS2 experimental and theoretical integrations. ............................................................... Table II -4. CardS3 experimental and theoretical integrations. ...............................................................

Table III - 1 .

 III1 Polymerization temperatures of (cardanol/aniline) PBz cured with 1 mol% catalyst. 156 .........................................................................................................................................................................

	Table III -2. Thermal properties Bz materials from reaction between m1 and carboxylic-
	containing Bz co-monomers m2, m3, and m4.

158 ............................................................................................ Table III -3. Reaction times of synthesis of Bz monomers in CHCl3 at reflux with increasing diamine chain length. 162 ..............................................................................................................................................

Table III - 4 .

 III4 Melting point (Tm) and polymerization temperature (Tp) of model aromatic-di-Bz monomers and Tg of their corresponding aromatic-PBz materials. .........................................................

Table III - 5 .

 III5 Thermal properties of aliphatic-di-Bz monomers, synthetized from various chain length linear diamines and phenol, and Tg of their corresponding aliphatic-PBz materials. ........ Thermal properties of vanillin-based Bz monomers, synthetized from monofunctional amines or diamines, and Tg and T5% of their corresponding PBz materials. .................

	Table III -6.

Table III - 7 .

 III7 Thermal properties of guaïacol-based Bz monomers, synthetized from monofunctional amines or diamines, and Tg and T5% of their corresponding PBz materials. .................

Table III - 8 .

 III8 Thermal properties of lignin-derivative-based Bz monomers, synthetized from mono-functional amines or diamines, and Tg and T5% of their corresponding PBz materials. ...

Table

III -

9. Thermal properties of eugenol-based Bz monomers, synthetized from monofunctional amines or diamines, and Tg and T5% of their corresponding PBz materials. ................. Table III -10. Thermal properties of coumarin-based Bz monomers, synthetized from monofunctional amines or diamines, and Tg and T5% of their corresponding PBz materials. ................. Table III -11. Thermal properties of cardanol-based Bz monomers, synthetized from monofunctional amines or diamines, and Tg and T5% of their corresponding PBz materials. ................. Table III -12. Thermal properties of urushiol-based Bz monomers, synthetized from amines or diamines, and Tg and T5% of their corresponding PBz materials. ............................................................

Table III -13. Assignments of the 1

Table III -15. Assignments

 III

of the 1 H NMR peaks of the di-cardanol benzoxazine monomer and their theoretical and experimental integrations. ........................................................................................... Table III -16. Assignments of the 1 H NMR peaks of the asymmetric Vani-Card Bz monomer and their theoretical and experimental integrations. ........................................................................................... Table III -17. Thermal properties of symmetric and asymmetric di-benzoxazine monomers. Values are obtained from DSC (a), TGA (b) and rheology (c) analyses. ................................................ Table III -18. Thermal properties of symmetric and asymmetric PBz materials. Values are obtained from DMA (a), and TGA (b) analyses. ...............................................................................................

Table IV - 1 .

 IV1 Thermomechanical properties of CDGE cured with IPD or Jeff400, compared to BADGE/IPD network. 213 ............................................................................................................................................

Table I -1. 10 CNSL type CNSL phenolic components (%)

 I

		Anacardic acid (%)	Cardanol (%)	Cardol (%)	2-methylcardol (%)
	Natural CNSL	74.1-77.4	1.2-9.2	15.0-20.1	1.7-2.6
	Technical CNSL	1.0-1.8	74.7-84.7	11.6-18.9	2.2-5.2

Table I -

 I

1. Composition of the phenolic components in natural and technical CNSL.

  11

Table I -

 I 2 summarizes the abundances of the different unsaturations as a function of the employed characterization technique. It can be observed that depending on the characterization technique and on the origin of the product the unsaturation abundances can slightly vary.

	Cardanol side chain	Saturated	Monoene (%)	Diene (%)	Triene (%)
	unsaturations (%)	(%)
	Employed technique
	Molecular distillation	-	60.0	10.0	30.6
	Silver ion chromatography	5.4	48.5	16.8	29.3
	TLC-GLC	2.7	29.5	16.6	51.2
	TLC-mass spectroscopy	2.0	31.3	15.2	51.5

Table I - 2 .

 I2 Composition of the abundances of the constituents of cardanol by various techniques.10

47 Compound CMC (mol/L) Surface tension at CMC (mN/m) sulfonated-3-pentadecyl phenyl acrylate

  surfactant. Nevertheless, no evaluation of the influence of the reactive surfactants on materials elaboration were reported byKattimuttathu et al..

	8.7 x 10 -5	35.52

sodium-2-acryloxy ethan- 1-oxy(3-pentedecyl) benzene sulfonate

		1.7 x 10 -5	31.61
	sodium dodecyl sulfonate	0.37	32.25

Table I -4. Physico-chemical properties of the reactive surfactants compared to the properties

	of standard non-reactive sodium dodecyl sulfonate anionic surfactant.
	3.2.2 Non-ionic surfactants
	Non-ionic surfactants may also be synthetized from cardanol, especially polyethoxylates (Figure
	I -17) that are commonly based on fatty alcohols or alkylphenols. 27, 48 Their properties were
	characterized by measuring their reduction in surface tension of water by dilute solutions (1 %)
	of polyethoxylates, and determine the optimum ethoxylate chain length. It was found that
	cardanol polyethoxylate with a C8 ethoxylate chain length showed similar surfactant properties
	than traditional t-nonylphenol polyethoxylate.

-5). Yields (%) of phase transfer catalysed reactions quaternary ammonium salt

		KMnO4 oxydation	NaClO oxydation	Williamson ether
				synthesis
	cardanol based	76	67	76
	R = CH3
	cardanol based	74	27	98
	R = CH2CH3
	cardanol based	60	26	84
	R = CH2CH2CH3
	Aliquat ®	64	49	60

Table I -5. Isolated

 I product yields (%) of phase transfer catalysed reactions.49 It is worthy to note that such ammonium salts can find applications for the functionalization of fillers, like mineral clays. Verge et al.50 reported the synthesis of an ammonium surfactant from cardanol for the compatibilization and dispersion of sepiolite clay into epoxy thermoset. Monoepoxidized cardanol -commercially available NC-513 -was reacted with ethylene diamine and protonated in acid medium (FigureI

-19). Cardanol

  -based ammonium surfactants were found to enhance the compatibility between sepiolite clay and epoxy networks. The studies dealing with these cationic cardanol-based surfactants are developed in Chap III.

°C, air) Tmax (°C, air) MLO 91 225 MLO + 1 % A1 171 246 MLO + 1 % BHT 164 221 MLO + 1 % IRGANOX 166 230 Table I -7. DTA measurements describing antioxidants effects of various antioxidants in MLO

	the structures conjugation. Further studies on cardanol-based phosphate antioxidants
	compounds (A4
	(A1, Figure I -25) by alkylation of hydrogenated
	cardanol was reported to reduce the formation of oxidation products in mineral lubricant oil
	(MLO). Differential Thermal Analysis (DTA) of mineral lubricant oil with various antioxidants
	such as cardanol-based 5-n-pentadecyl-2-tert-butylphenol (A1) and currently used 2,6-di-t-
	butyl-4-methylphenol (BHT, an alkylphenol) and IRGANOX® (a diphenyl phosphate) are
	summarized in Table I -7. The higher degradation temperatures were recorded for MLO
	modified with the cardanol-based antioxidant, Tmax = 246 °C, justifying its effective antioxidant
	properties.
	Sample Ti (under air atmosphere. 59 (Ti: initial thermal degradation temperature, Tmax: degradation
	temperature.)
	The antioxidant effect of cardanol-based organophosphate compounds (A2, Figure I -25) in
	mineral lubricant oil (MLO) was also studied. 60 The organophosphate antioxidant compound (A2)
	was synthetized by alkylation of hydrogenated cardanol, followed by reaction with diethyl
	chlorophosphate. Its antioxidant effectiveness was demonstrated by DTA measurements of MLO
	with the cardanol-based phosphate compound and compared to MLO with alkylphenol and
	diphenyl phosphate antioxidants (Table I -8).
	The antioxidant effectiveness of cardanol-based phosphate compound is proven by the higher
	initial thermal degradation temperature (Ti = 156 °C) than for mineral oil without antioxidant (Ti
	= 91 °C). Furthermore, its antioxidant effectiveness is comparable to those of current alkylphenols
	or diphenyl phophates. The good thermo-oxidative stability of cardanol-based phosphate
	compound can be explained by the bulkier substituent on ortho and para positions, increasing

and A5, Figure I -25) reported

  similar results, and confirmed their efficient antioxidant action for mineral oils.

61 Sample Ti (°C, air) Tmax (°C, air)

	MLO	91	226
	MLO + 1 % A2	156	204
	MLO + 1 % alkylphenol	178	239
	MLO + 1 % diphenyl phosphate	152	201
	Table I -8. DTA measurements describing antioxidants effects of various antioxidants in MLO
	under air atmosphere. 60 (Ti: initial thermal degradation temperature, Tmax: degradation
	temperature.)
	With the aim of combining the antioxidant properties of hydroxyl 4-thiaflavane compounds and
	the amphiphilic property of cardanol, Amorati et al. 62 proposed the synthesis of a cardanol-based
	4-thiaflavane anti-oxidant (A3, Figure I -25) by Diels-Alder reaction. The rate constants for the
	reaction with peroxyl radicals were measured by studying the autoxidation of styrene
	(monitoring of the oxygen consumption) at 30 °C in presence of the synthetized antioxidant
	compounds. The cardanol-based 4-thiaflavane antioxidant (A3) appeared very efficient because
	it displayed rate constants, for reaction with peroxyl radicals, from 50 to 70 times higher than
	hydrogenated cardanol, independently from the medium used to run the measures (

Table I -9). kinh/10 5 M -1 s -1 Measurement medium

	endows hydrophobic properties to the material as well as flexibility on account of internal
	plasticization.
	Styrene/PhCl	Styrene/H2O	H2O/PhCl
	Cardanol	0.1	0.1	1
	A3 (R = H)	7.0	5.2	0.7
	A3 (R = CH3)	7.0	5.3	0.9
	Table I -9. Inhibition rate constants (kinh) obtained by studying the AIBN initiated autoxidation
	of styrene at 30 °C in homogeneous solution using chlorobenzene (PhCl) as a solvent, or in a
	two-phases water/styrene system. 62
	4 Cardanol-based polymers
	Due to its particular chemical structure, cardanol is used as a building block for the synthesis of
	many different polymer materials such as phenolic or epoxy resins, as well as polybenzoxazines
	or polyurethane thermosets. The three available reactive sites on cardanol enable the synthesis
	of numerous kinds of cardanol-based polymers. Furthermore, the presence of the C15 alkyl chain

Table I -10. Thermal

 I

		Tg (°C)	T10% (°C)	Tmax (°C)
	CAP1	31.6	302.5	346
	CAP2	16.1	291.8	333

of CAP1 and CAP2 based PU materials.

77

(T10% is the temperature at 10

Table II - 1 .

 II1 Example of fillers for the elaboration of nanocomposites.83

	Chemical nature	Filler examples
	Element	Graphite
	Metal chalcogenides	(PbS)1.18, (TiS2)2, MoS2
	Carbon and Carbon oxides	Graphite, Graphite oxide, Carbon Nanotubes
	Metal phosphates	Zr(HPO4)
	Clays and layered silicates	Montmorillonite, hectorite, saponite, fluoromica, fluorohectorite, Vermiculite,
		kaolinite, magadiite
	Layered double hydroxides	M6Al2(OH)16CO3•nH2O, M=Mg, Zn
	Other	Nanocellulose, Nanochitin
		83

Table II -2. CardS1

 II appeared at 3.4 ppm with Iexp = 4.3 H (Ith = 4 H), confirming the mono-addition of NC-513 on one TAEA moiety.

	Chemical shift (ppm)	Assignment	Iexperimental	Itheoretical
	0.91	Alkyl chain CH3	1.8 H	1.7 H
	1.31	Alkyl chain CH2	13.5 H	13.6 H
	1.59	-CH2-Ar	2.3 H	2H
	2.04	-CH2*=CH-	3.4 H	3.1 H
		Amine moiety -CH2-
	2.28 -2.95	and cardanol moiety	15.6	16.1
		=CH-CH2*-CH=
	3.04	-NH2	4.3	4
	3.84 -4.23	H in α to O	3.5	3
	4.93 -5.90	Alkyl chain CH=	4.8	4.5
	6.68 -7.21	H-Ar	4	4

experimental and theoretical integrations.

Table II - 3 .

 II3 CardS2 experimental and theoretical integrations.

	Chemical shift (ppm)	Assignment	Iexperimental	Itheoretical
	0.91	Alkyl chain CH3	1.8 H	1.7 H
	1.32	Alkyl chain CH2	13.0 H	13.6 H
	1.61	-CH2-Ar	2.2 H	2H
	2.04	-CH2*=CH-	3.3 H	3.1 H
		Amine moiety -CH2-
	2.47 -2.93	and cardanol moiety	8.6	8.1
		=CH-CH2*-CH=
	3.18	-NH2	2.5	2
	3.86 -4.30	H in α to O	3.4	3
	4.90 -5.93	Alkyl chain CH=	4.7	4.5
	6.64 -7.25	H-Ar	4	4

H NMR spectrum (Solvent CDCl3)

.

Table II -

 II

	Chemical shift (ppm)	Assignment	Iexperimental	Itheoretical
	0.91	Alkyl chain CH3	1.8 H	1.7 H
	1.32	Alkyl chain CH2	13.5 H	13.6 H
	1.61	-CH2-Ar	2.2 H	2H
	2.04	-CH2*=CH-	3.6 H	3.1 H
		Amine moiety -CH2-
	2.47 -2.93	and cardanol moiety	13.6	14.1
		=CH-CH2*-CH=
	3.86 -4.30	H in α to O	3.4	3
	4.90 -5.93	Alkyl chain CH=	4.9	4.5
	6.64 -7.25	H-Ar	4	4

at 3.86-4.30 ppm, Iexp = 3.4 H, and Ith = 3 H.

Figure II -12. CardS3 1 H NMR spectrum (Solvent CDCl3). 4. CardS3 experimental and theoretical integrations.

  1.1.3 Effect of hydrogen bonding and π-π supramolecular interactions on polybenzoxazines properties Excellent properties were reported for PBz resins. NeverthelessIshida et al. 115 reported that, despite displaying high Tg's and high moduli, the crosslinking density of PBz resins remained very low in comparison to epoxy resins. Generally, high glass transition temperature is in correlation with the high crosslinking density.Wirasate et al. 128 studied the dependency of various hydrogenbonding infrared modes to understand the hydrogen-bonded structure in the PBz resins. They reported two types of hydrogen bonds within PBz materials. Both statistically distributed and conformationally preferred hydrogen bonding may contribute to the stiffness of the system and led to high Tg and high modulus polymer. The excellent properties of PBz resins have further been attributed to the hydrogen bonds within the materials by several other studies.[129][130][131][132][133]

Table III -

 III

	Catalyst	Polymerization temperature (°C)
	No catalyst	260.6
	MgCl2	193.1
	ZnCl2	207.1
	p-TsOH	206.0

-1, the use of 1 mol% of these catalysts enabled to significantly reduce the polymerization temperature, even below 200 °C in the case of MgCl2. 1. Polymerization temperatures of (cardanol/aniline) PBz cured with 1 mol% catalyst.

156

-14.

	Chemical shift (ppm)	Assignment	Iexperimental	Itheoretical
	3.02	N-CH2*-CH2 [5]	3.70 H	4.00 H
	3.95	O-CH3 [6]	Ref 6.00 H	6.00 H
	4.13	Ar-CH2-N [3]	4.01 H	4.00 H
	5.08	O-CH2-N [4]	4.02 H	4.00H
	7.13	H-Ar [1, 2]	1.99 H	2.00 H
	7.32	H-Ar [1, 2]	1.99 H	2.00 H
	9.81	(C=O)H2 [7]	2.00 H	2.00 H

Table III -14. Assignments

 III

of the

1

H NMR peaks of the di-vanillin benzoxazine monomer and their theoretical and experimental integrations.

Table III -

 III 15. Assignments of the 1 H NMR peaks of the di-cardanol benzoxazine monomer and their theoretical and experimental integrations.

	shift (ppm)	Assignment	Iexperimental	Itheoretical
	0.86 -0.94	-CH3 [a1]	4.08 H	3.54 H
		-CH2
	1.23 -1.43	[b1, c1, d1, e1, f1, g1,	27.58 H	27.12 H
		h1, i1, j, k, l, m, n]
	1.54 -1.64	-CH2 in β from Ar [n]	4.00 H	4.00 H
	1.98 -2.09	CH2*=CH [c2, f2, i2]	7.47 H	6.20 H
	2.49 -2.57	CH2-Ar [o]	4.47 H	4.00 H
	2.76 -2.87	CH2*(=CH)2 [c3, f3]	4.74 H	4.20 H
	2.99	N-CH2*-CH2 [6, 7]	Ref 4.00 H	4.00 H
	4.03	Ar-CH2-N [4]	3.98 H	4.00 H
	4.89	O-CH2-N [5]	4.00 H	4.00 H
	4.96 -5.88	CH= [b2, d2, e2, g2, h2, a2]	1.69; 7.55; 0.94 H	1.64; 6.48; 0.82 H
	6.60 -6.90	H-Ar [1, 2, 3]	2.01; 2.07; 1.93 H	2.00; 2.00; 2.00 H

Table III - 16 .

 III16 Assignments of the 1 H NMR peaks of the asymmetric Vani-Card Bz monomer and their theoretical and experimental integrations.

		[9]
	4.88	O-CH2-N [5]	cardanol	1.98 H	2.00 H
	4.96 -5.88	CH= [b2, d2, e2, g2, h2, a2]	cardanol	1.00; 3.76; 0.46 H	0.82; 3.24; 0.41 H
	5.08	O-CH2-N [8]	benzoxazine	1.99 H	2.00 H
	6.60 -6.99	H-Ar [1, 2, 3]	cardanol	1.07; 1.06; 1.00 H	1.00; 1.00; 1.00 H
	7.12 -7.34	H-Ar [10, 12]	benzoxazine	1.00; 1.01 H	1.00; 1.00 H
	shift (ppm) 9.81	Assignment (C=O)H [11]	Compound reference benzoxazine	Iexperimental 1.01 H	Itheoretical 1.00 H
	0.85 -0.96	-CH3 [a1]	cardanol	2.04 H	1.77 H
		-CH2
	1.23 -1.41	[b1, c1, d1, e1, f1, g1, h1, i1, j, k, l, m,	cardanol	13.53 H	13.56 H
		n]
	1.54 -1.64	-CH2 in β from Ar [n]	cardanol	Ref 2.00 H	2.00 H
	1.98 -2.09	CH2*=CH [c2, f2, i2]	cardanol	3.41 H	3.10 H
	2.49 -2.56	CH2-Ar [o]	cardanol	2.00 H	2.00 H
	2.75 -2.87	CH2*(=CH)2 [c3, f3]	cardanol	2.36 H	2.10 H
	2.95 -3.09	N-CH2*-CH2 [6, 7]	benzoxazine	3.99 H	4.00 H
	3.86 -3.94	O-CH3 [13]	Benzoxazine	Ref 3.00 H	Ref 3.00 H
	4.01	Ar-CH2-N [4]	cardanol	1.99 H	2.00 H
	4.13	Ar-CH2-N	benzoxazine	1.99 H	2.00 H

Table IV - 1 .

 IV1 Thermomechanical properties of CDGE cured with IPD or Jeff400, compared to BADGE/IPD network.213 Similar studies were undertaken byChrysanthos et al., 212 who reported the elaboration of CDGE/IPD networks and compared them to BADGE/IPD networks. Analogous results as in Jaillet et al. were found for a formulation ratio of 1/1 (CDGE/IPD equivalent).

		-1). The crosslinking density was calculated by the
	following formula developed by Webster et al. 214 :
		E' = 3ʋeRT
	The lower crosslinking density of the CDGE/IPD network in comparison to the BADGE/IPD
	network is explained by the higher flexibility and lower EEW of CDGE.
	Epoxy/amine (amine equivalent)	Tg (°C)	E' (MPa) at Tg + 60 °C	ʋe (10 3 mol/m 3 )
	BADGE/IPD	158	19.6	4.8
	CDGE/IPD	50	3.2	1
	CDGE/Jeff400	15	2.6	1

  The reference materials from EDBz and CDGE, as well as the IPN materials with various compositions, were elaborated by first mixing the CDGE compound and the EDBz compound at 100 °C and degasing during 1 h at 100 °C, followed by the addition of the IPD hardener in stoichiometric ratio to the CDGE monomer. The mixtures were then transferred to a U-shaped mold. The previously determined curing program of 16 h at 100 °C, 1 h at 160 °C, 2 h at 180 °C, 2 h at 200 °C and 30 min at 220 °C was applied to each material.IPNs with different EDBz contents ranging from 20 % to 80 % by weight were synthetized, while keeping the same ratio between CDGE and the IPD hardener. All investigated CDGE/EDBz compositions are reported in weight-by-weight ratio. Thus, an IPN obtained from a mixture of 0.80 g of CDGE and 0.20 g of EDBz will be noted as poly(CDGE)/poly(EDBz) (80/20) IPN.

	2.3 Poly(CDGE)/poly(EDBz) IPNs
	2.3.1 Poly(CDGE)/poly(EDBz) IPN Material elaboration

  , 1.32 (m, -CH2 from alkyl chain, exp 13.0 H, th 13.6 H), 1.61 (t, -CH2-Ar, exp 2.2 H, th 2 H), 2.04 (m, -CH2*=CH-, exp 3.3 H, th 3.1 H), 2.47-2.93 (m, -CH2-from amine moiety and =CH-CH2*-CH= from Cardanol, exp 8.6 H, th 8.1 H),

Remerciements J'adresse mes sincères remerciements au Professeur Frédéric Vidal, directeur du Laboratoire de

Physico-Chimie des Polymères et des Interfaces, pour son accueil au sein de son laboratoire afin de

List of Abbreviations

AAF

Available Amino Functionalities The characteristic peaks of the cardanol compound were observed, especially aromatic C-H stretching at 3009 cm -1 , strong CH2 and CH aromatic and aliphatic absorption band at 2927-2854 cm -1 arising mainly from the long alkyl chain and aromatic C-H out of plane deformations at 1637 cm -1 . In addition, characteristic peaks of amine functions were also observed, such as N-H

BADGE

stretching absorption band at 3287 cm -1 , C-N stretching at 1101 cm -1 , and the ethers C-O stretching at 1048 cm -1 .

2.2.2

Characterization by 1 H NMR with diverse compositions, which lead to complex NMR spectra. Nevertheless, the number of aromatic protons is a good reference because only the cardanol is bearing aromatic protons. Thus for a mono-addition of NC-513 on TAEA for example, only 4 aromatic H should be observed. In the present case, the estimation of 4 aromatic H as integration reference seemed to be correct, as 4.53 aromatic H were integrated for the integration of the global CardS1 corresponding spectrum (Total number of proton: exp = 54.67 / th = 55).

In conclusion, the NRM spectra and the integrations let pretend to a majority of mono-addition of NC-513 on the different amine-containing molecules, confirming the structures of the synthetized surfactants obtained by IR characterization.

Characterization by MALDI-TOF/MS

The chemical structures of the three synthetized surfactants were further characterized by MALDI/TOF-MS analysis. The surfactant experimental mass could thus be compared to the expected mass in order to fine-tune their chemical structure.

In order to characterize the molecules, α-cyano 4-hydroxycinnamic acid (CHCA) was used as protic matrix for MALDI-MS analysis. By using this matrix, only the protonated molecule should be detected.

Cardanol is a product composed of four different molecules, varying through their alkyl chains unsaturation degree. As a result, the MALDI-MS spectrum obtained from compounds synthetized from cardanol displayed a fingerprint pattern, allowing the easy recognition of cardanolcontaining compounds by MALDI-MS analysis. 51 For example, in the case of the CardS1 compound, synthetized with TAEA (M = 146 g/mol), a peak spreading from 501 to 507 m/z was expected for the mass peak of a mono-addition of TAEA on the epoxidized cardanol [CardS1+H] + .

Indeed, the molar mass of NC-513 is varying from M = 354 g/mol and M = 360 g/mol, depending on the alkyl side chain unsaturation degree.

For each surfactant, the MALDI-MS analysis in Materials with high Tg typically ranging from 170 °C to 260 °C were obtained with aromatic diamines as bridging groups. Higher flexibility of the aromatic diamine backbone, for example in the case of 44appe or ndpa, induced a lower Tg, 172 °C and 170 °C respectively, than for Bz with more rigid aromatic diamine such as 1,4-phenylenediamine (Tg = 260 °C). However, the relatively high melting temperatures of aromatic-di-Bz monomers (above 120 °C) complicate the materials processing (molding and shaping), due to the short processing windows Tproc, defined as the difference between the monomer melting temperature (Tm) and its polymerization temperature (Tp).

Guaïacol

Guaïacol is another lignin-derivative phenolic compound, also studied as precursor for the design of bio-based benzoxazine monomers.

Up to now, to the best of our knowledge, only mono-functional Bz monomers from guaïacol were reported in the literature. The effect of two different bio-based primary amines on the thermal properties of the monomer and corresponding PBz material were studied (Table III -7). DSC measurements revealed a Tg of 82 °C for a material obtained from the reaction between guaïacol and stearylamine (Table III -7, line 1). When furfurylamine was used for the synthesis of guaïacol-based Bz monomer, an increase of the Tg to = 148 °C was reported (Table III -7, line 2).

The authors did not give any information about the monomers melting points: the PBz materials were shaped by solution casting of the monomers dissolved in acetone. due to the symmetric nature of the monomer, the functionalities that could be added are limited by the chosen phenolic derivative.

Bz monomer

An elegant approach of adding different functionalities on Bz monomers consists of designing asymmetric di-Bz monomers, using for example a diamine as bridging group between two phenolic derivatives exhibiting each a particular functionality. Different synthesis strategies were developed in order to access asymmetric di-Bz monomers.

The first example dealing with the synthesis of an asymmetric di-Bz monomer was reported recently (2013). 201 Aminophenol was reacted with the aldehyde group of a hydrobenzaldehyde compound to form an imine linkage between the two phenolic compounds (Figure III -21). The imine was reduced by using NaBH4 and the oxazine rings were further formed using -Di-vanillin benzoxazine monomer

The Values are obtained from DSC (a), TGA (b) and rheology (c) analyses.

In Table III - The chemical structure of CDGE is thus very complex and composed of a significant number of molecules. However, the lack of purification of this commercial product is not a drawback to its use, and it is worthy to remind that even very commonly used BADGE pre-polymer (DER332) is composed of oligomers and it is the reason why its reactivity is averaged and given in EEW. The addition of an amine achieved a much faster polymerization at mild temperatures, and the efficiency of the diamine onto the ROP of benzoxazine is directly depending on its basicity. The authors of this work evidenced the following order: arylamine > alicyclic amine > alkylamine.

In summary, it is easy to expect that mixtures of epoxy /diamines /benzoxazines will all react together if the curing is not controlled. Indeed, Wang et al. 227 evidenced that the morphology of the networks may be affected by the curing process. The curing of a ternary system composed of IPNs can be synthetized from two synthetic pathways: sequential synthesis or in-situ synthesis.

Determination of the suitable di-amine hardener

The choice of the diamine hardener used for the polymerization of the CDGE is essential for the elaboration of IPNs. In order to avoid the formation of polymer co-networks, a diamine nonreactive towards the EDBz monomer and allowing the curing of CDGE at low temperature will be needed.

In order to find a suitable hardener for the epoxy system, various diamine compounds were tested by the following procedure: The CDGE was heated at the EDBz monomer melting temperature (Tm = 116 °C for EDBz). The amine hardener was then added to the mixture in system (at the end of the thermal treatment) were carried out to confirm the sequential network formation and their total cross-linking. To further validate the curing conditions, soluble fractions of the samples were extracted with chloroform after the first curing step and on the final material.

The DSC analysis and the solvent extraction were achieved in order to estimate the amount of

Evaluation of poly(EDBz) formation

The CDGE system was then crosslinked in presence of EDBz monomer in order to verify that EDBz A lone mechanical relaxation around 70 °C is observed for these materials, close to the mechanical relaxation of single poly(CDGE) as it is the main component of those IPNs. As no additional transition corresponding to a poly(EDBz) rich phase is observed at higher temperature, it can be assumed that the poly(EDBz) is entangled at nanometer scale within the poly(CDGE) network.

Estimation of the morphology by theoretical models

The determination of the IPN materials morphology is very important in order to relate it to the materials properties. Despite several characterization attempts, particularly through AFM in tapping mode or elementary EDX-SEM analysis, we remained unable to determine the morphology of the poly(CDGE)/poly(EDBz) IPN materials when phase separation occured.

Consequently, with the aim to obtain an estimation of the materials morphology, a comparison between the IPN materials experimental thermo-mechanical data and those of theoretical models were achieved. Indeed, IPN can be multiphase systems for which the storage modulus obtained by DMA can be correlated to their composition and morphology. Several theories have been developed to this aim. Most of the theories consider a macroscopic isotropy of the systems and a perfect adhesion between the different phases.

Kerner described a model for a matrix in which spherical inclusions are dispersed over the whole composition range. 241 As this model does not take into account the interactions between the dispersed inclusions and the continuous matrix, it predicts accurately the polymers blend properties when the volume of the dispersed phase is low.

The material shear modulus G is defined as follow:

Where 1 is the continuous phase and 2 is the dispersed spherical inclusions, G is the shear modulus, ɸ2 is the volume fraction of the inclusion spheres, and α is a function of the matrix Poisson ratio according to the following equation:

Where ν is the Poisson's ratio.

A model which predicts a phase inversion at middle-range composition was predicted by Budiansky. 242 In the first case, the material is formed by a continuous phase 1 in which a second phase -2 -is dispersed as long as the volume fraction ɸ2 of the second phase is lower than 0.5.

When ɸ2 is higher as 0.5, a phase inversion occurs and the phase 2 becomes continuous with phase 1 being dispersed within it. For this model, the shear modulus G observes the following equation: Indeed, the first formed network is necessarly continuous. 246 The poly(CDGE) network is thus continuous. This is not in accordance with the Budiansky model whereas it is with Davies model that consideres the second formed network as also continuous. Therefore, the IPNs of the studied range could thus be considered as two co-continuous phases. Therefore, poly(CDGE)/poly(EDBz)

IPNs whether they are homogeneous at the DMA scale or co-continuous phase separated have mechanical properties that are averaged by the volume proportion of polymers. The IPN morphology is adequate for combination of both polymer properties, i.e. PBz network should efficiently prevent the water diffusion, in addition of clear reinforcement of the thermal and mechanical properties of the materials, whatever their composition.

Behaviour toward water exposure

In order to verify that the introduction of poly(EDBz) in IPNs is a viable strategy to prevent the water diffusion within the material, swelling tests were achieved and monitored by DSC analyses.

The poly(CDGE)/poly(EDBz) IPN materials -varying from 80/20 to 20/80 in ratio -as well as due to its very low cross-linking density-, and is thus not suitable for almost all the coatings applications. A way to tackle this issue is to reinforce at the macromolecular scale by the formation of interpenetrating polymer networks (IPN) with polybenzoxazine.

The aim of the chapter was to prove the feasibility of the elaboration of IPNs between the poly(CDGE) and the poly(EDBz) networks. Theoretical models were used to identify the morphology of the two phases IPN. These theories are based on the evolution of the storage moduli of the materials as a function of their composition. Experiment fits in very high accordance to the Davies model. According to this theoretical model and to the occurring chemistry reactions, a co-continuous matrix should be obtained for the systems with EDBz content above to 50 %. In spite of numerous attempts (atomic force microscopy, scanning electron microscopy), it was not possible to observe these morphologies and up to now the viability of this model is not confirmed.

Finally, swelling tests in water at 80 °C were performed on all the set of materials (i.e. with EDBz content ranging from 0 to 100 wt %). Interestingly, it was observed that the incorporation of poly(EDBz) leads to a significant drop of the swelling of poly(CDGE) in water. Evolutions of the melting enthalpies of water were recorded on the swollen samples by differential scanning measurements, as this method is very sensitive. Two endotherms of melting were observed at 0 °C and -10 °C depending on the materials composition, corresponding respectively to bulk-and confined-water within the networks. In neat poly(CDGE) networks, water molecules are free, with a melting enthalpy of 27.31 J/g. Increasing poly(EDBz) content leads to a confinement of the water molecules, and to a decrease of the total melting enthalpy.

Annex: Materials and Methods For MALDI analyses, samples were submitted to a solvent-free preparation, consisting of grinding the matrix together with the analyte with a mortar and a pestle. The matrix/analyte mass ratio was optimized for each sample, around 1/10 appearing to be a quite universal ratio for the clay mineral samples, while a 50/1 ratio being a routinely used for the organic analytes such as cardanol-based surfactants.

Trans-2-[3-(4-tert-butylphenyl)-2-methyl-2propenylidene]malononitrile (DCTB) was used for the analysis of surfactants and clays (no salt, to detect species protonated prior to the LASER irradiation), α-cyano 4-hydroxycinnamic acid (CHCA) was only used for the surfactants (no salt, to promote the protonation of the amine groups).

Annex: Figures