The reduction in the consumption of fossil fuels is one of the most significant social and economic challenges of the modern era. The chemical industry, among others, still relies heavily on materials derived from oil to develop novel products at the cost of a non-negligible carbon footprint. More specifically, the use of polymers for commodity products as well as high-performance materials accounts for 7% of the consumption of fossil fuel, a figure that keeps on increasing. [1][2][3][4] These products include specialty materials like thermoplastic elastomers (TPEs), pressure sensitive adhesives (PSAs) and coatings, which have become increasingly attractive, due to their unique mechanical properties and excellent processability. 5, 6 Therefore, in order to reduce the fossil fuel dependence and the associated carbon footprint, the use of waste products and renewable natural resources as feedstock for polymer materials is an attractive opportunity. However, renewable polymers only have a small share of the whole Chapter 1 2 polymer market. This is due to the high cost and limited range of properties compared to the synthetic polymers produced from the petroleum chemical. [7][8][9] Therefore, it remains a challenge to design polymers with similar performances and cost as petroleum-based polymers. [10][11][12] According to the European Bioplastic Association, 13 the term of 'biobased' means that the material or product is (partly) derived from biomass (plants). According to the market data compiled by the European Bioplastic Association in collaboration with nova-Institute, global bioplastics production capacity is set to increase from around 2.11 million tonnes in 2018 to approximately 2.62 million tonnes in 2023 (Figure 1.1). Chapter 1 6 Otto of rose Rosa spp. Geraniol, citronellol (>70%) Geranium Pelargonium spp. Geraniol, citronellol Lemon Citrus limon Limonene (90%) Lemon grass Cymbopogon spp. Citral, citronellal (75/85%) Citron scented Eucalyptus citriodora Citronellal (~70%) Spearmint Mentha spicata and Menta cardiac Carvone (55/70%) Peppermint Mentha piperita Menthol (45%) Continental lavender Lavandula officinalis Linalool, linalyl acetate (much), ethyl penthyl

The renewable raw materials can be divided into three groups based on the origin; a) vegetable resources (cellulose, lignins, terpenes, starch, and vegetable oils), b) animal resources (chitosan, chitin and proteins), and c) bacteria polymers (bacteria cellulose and poly(hydroxyalkanoate)). Cramail et al. recently reviewed the use of lignin-based materials (prepared from vanillin, ferulic acid, guaiacol, syringaldehyde and 4-hydroxybenzoic acid) to produce thermoplastics and thermosets. 14 The Chapter 1 4 mechanical properties of the final polymers are affected by the substituents on the aromatic ring, and it was discovered that the presence of the methoxy groups led to an increase of impact strength. Among the plethora of reagents available, cardanol emerged as a valuable resource to modify the properties of epoxy-resins. Indeed, the mechanical properties were improved when the cardanol content was increased to 40%. 15 Another renewable resource worth mentioning is isosorbide, which can be used in the synthesis of polyesters and/or thermosets with high glass transition temperature (Tg = 130 ˚C) and good thermal stability. 16 In addition, the chain extension of isosorbide with n-butyl acrylate was also performed to yield soft/hard diblock copolymers, in which the two phase separation was observed with the detection of two Tgs.

Terpenes

One class of abundant vegetal materials that can be exploited is the terpene family. Terpenes are obtained by using steam distillation or by extraction of pine stumps. It is also one of the main byproducts of the Kraft process (Black liqueur), which is used in the paper industry to extract lignin from wood in the production of pulp. 17 The main components are αand β-pinene. Terpenes are commonly utilized in fragrance and flavor formulations (e.g. limonene, camphor). Most of the terpenes are either branched or cyclic molecules that contain one or more carbon-carbon double bond. Representative structures of some common terpenes are shown in Figure 1.2. When terpenes are chemically modified, for example by oxidation or rearrangement of the carbon skeleton, the resulting compounds are generally referred as terpenoids. The main terpenoid compounds found in some essential oils can be seen in Table 1. Scheme 1.2. An alternative mechanism of α-pinene cationic polymerization.

Thus, only oligomers of α-pinene can be obtained. Therefore, the vast majority of pinene polymerization involves the utilization of β-pinene. The earliest work on cationic polymerization of β-pinene employed Lewis acid metal halides like aluminium chloride, or ethyl aluminium dichloride as catalysts. [24][25][26] The general polymerization mechanism of cationic polymerization of β-pinene is presented in Scheme 1.3. Later, other Lewis acid initiators such as SnCl4, TiCl4, BF3 and Et2AlCl in various solvents and temperatures were also investigated. 27 Moreover, the cationic polymerization of βpinene was tested under microwave irradiation using AlCl3 as the initiator, which was shown to proceed rather rapidly and smoothly. 28 However, only low molar masses (< 4000 g.mol -1 ) were obtained.

Chapter 1 10 Scheme 1.3. Mechanism of the cationic polymerization of β-pinene. 29 The living cationic polymerization of β-pinene was reported by Sawamoto et al. [29][30][31] The proposed polymerization mechanism is the attack of β-pinene on the cationic initiator form a tertiary carbocation, which then undergoes rearrangement of the pinene skeleton with the formation of a p-menthane type repeating unit. 29,31 The main advantage of the living cationic polymerization is that it allows synthesizing block copolymers. The synthesis of block copolymers of β-pinene with styrene and pmethylstyrene (pMeSt), 31,32 isobutylene 33 and other co-monomers 34,35 using living cationic polymerization has been reported. Although most block copolymers prepared via living cationic polymerization had relatively low molecular weights, molecular weights up to 40,000 g.mol -1 could be achieved using H2O/EtAlCl2 co-catalyst system, at low temperature (-40 to -80 ℃). 36,37 Recently, Kostjuk and co-workers 38 reported an effective initiating system for cationic polymerization of β-pinene using AlCl3 (AlCl3OPh2 or AlCl30.8EtOAc) under industrially attractive experimental conditions (room temperature, low co-initiator concentration, and the possibility to use nonchlorinated solvents). Poly(β-pinene)s with relatively high molecular weight (Mn = 9,000-14,000 g.mol -1 ) and good thermal properties were obtained. Free radical polymerization was also utilized to produce terpene containing copolymers. The copolymerization of β-pinene with conventional monomers such as methyl methacrylate (MMA), 39 styrene (S) 39 and acrylonitrile (AN) 40 resulted in limited incorporation of β-pinene monomer into the copolymer due to low reactivity ratios, and hence low yields that were obtained.

More recently, a more convenient approach to incorporate terpenes by free radical polymerization was introduced by Tang et al., 19 in which rosin-based monomers bearing an acrylate moiety were prepared by esterification of pendant hydroxyl and acid groups. This allowed higher incorporation of the terpene-based materials into polymer matrices. Howdle et al. 41 utilized cyclic terpenes including βpinene to prepare (meth)acrylate-based monomers via oxidation and subsequent esterification of the hydroxyl groups. The free radical polymerization of those monomers resulted in high monomer conversions (> 95 %), yielding polymers with 𝐷𝑃 ̅̅̅̅ n up to about 100. The bio-based (meth)acrylic polymers displayed interesting Chapter 1 12 thermal properties, with Tgs ranging from room temperature to 120 °C. This was exploited to produce bio-based hard coatings after UV exposure in the presence of a thiol-based crosslinker. Lu and co-workers have reported the reversible additionfragmentation chain-transfer (RAFT) polymerization copolymerization of β-pinene with acrylic monomers. [START_REF] Ballard | Impact of Competitive Processes on Controlled Radical Polymerization[END_REF] Although reasonable control was achieved, the reactivity ratios are not favorable for the efficient incorporation of β-pinene and the control over the polymer microstructure was therefore limited.

Polymers derived from Limonene/Myrcene

Another interesting terpene is limonene, which can be obtained from the isomerization of pinene or as a byproduct of the citrus industry. 43 Limonene is a chiral molecule. The (R)-enantiomer represents 90-96 % of citrus peel oil, and its world production exceeds 70,000 tons per year. 44 Limonene was copolymerized with monomers such as MMA, 45 AN, 46 and S 47,48 , but poor incorporation of limonene was achieved due to the unfavorable reactivity ratios. In contrast, the use of phenylmaleimide as comonomer yielded highly regulated polymers with efficient incorporation of limonene into the polymer. [START_REF] Satoh | AAB-Sequence Living Radical Chain Copolymerization of Naturally Occurring Limonene with Maleimide: An End-to-End Sequence-Regulated Copolymer[END_REF] Using a trithiocarbonate based RAFT agent, a reasonable control over the molecular weight could be obtained, although dispersity of the polymers was greater than 1.5 in most cases. Limonene contains a C=C double bond, which can be converted to desirable functional groups by thiol-ene addition. Thiol-ene addition proceeds via a free radical chain mechanism and mainly produces anti-Markovnikov products. [START_REF] Griesbaum | Probleme und Möglichkeiten der radikalischen Addition von Thiolen an ungesättigte Verbindungen[END_REF] The thiol-ene addition consist in the initially formation of thiyl radical which then attacks the unsaturated substrate forming a carbon radical. Then, the carbon radical reacts with the thiol molecule to give the final product and a new thiyl radical, thus propagating the radical chain (Scheme 1.4). [START_REF] Firdaus | Terpene-Based Renewable Monomers and Polymers via Thiol-Ene Additions[END_REF] Scheme 1.4. Mechanism of Thiol-ene addition.

Jones et al [START_REF] Janes | Reaction of monoterpenoids with hydrogen sulphide to form thiols and epi-sulphides of potential organoleptic significance[END_REF] prepared terpene-based thiol by reacting hydrogen sulfide with various monoterpenes including limonene, terpinolene, car-3-ene and pulegone in the presence of aluminium trichloride or tribromide leading to a mixture of thiols and sometimes additionally bridged epi-sulphides. The main product from the reaction of Chapter 1 14 limonene with hydrogen sulphide was p-menth-1-en-8-thiol, characteristic of the grapefruit flavor. On the other hand, the main product from pulegone was 8-mercaptotrans-p-menth-3-one, an important component of Buchu leaf oil. Limonene-based homopolymers were also formed via thiol-ene addition technique, [START_REF] Firdaus | Terpene-Based Renewable Monomers and Polymers via Thiol-Ene Additions[END_REF] displaying a relatively low molar mass and low Tg around -10 ℃.

Myrcene is one terpene that has gained interest in recent years. Hillmyer et al.

prepared high molecular weight polymer of poly(3-methylenecyclopentene) using a combination of ring-closing metathesis and cationic polymerizations. [START_REF] Kobayashi | Controlled Polymerization of a Cyclic Diene Prepared from the Ring-Closing Metathesis of a Naturally Occurring Monoterpene[END_REF] The final polymer exhibited a low glass transition temperature (Tg -28 ℃ ). Moreover, an elastomer copolymer was obtained by copolymerization of myrcene and styrene via emulsion cationic polymerization. High molecular weight (from 60 to 120 kg.mol -1 ) with relatively high dispersity (< 3.5) and single glass transition temperatures (from -40 to 15 ℃) were obtained. [START_REF] Trumbo | Free radical copolymerization behavior of myrcene[END_REF][START_REF] Hulnik | Aqueous cationic homo-and co-polymerizations of β-myrcene and Chapter 1 48 styrene: a green route toward terpene-based rubbery polymers[END_REF] Recently, Sarkar and Bhowmick synthesized a series of elastomer copolymers of myrcene with styrene, [START_REF] Sarkar | Terpene Based Sustainable Elastomer for Low Rolling Resistance and Improved Wet Grip Application: Synthesis, Characterization and Properties of Poly(styrene-co-myrcene)[END_REF] dibutyl itaconate [START_REF] Sarkar | Green Approach toward Sustainable Polymer: Synthesis and Characterization of Poly(myrcene-co-dibutyl itaconate)[END_REF] and methacrylates [START_REF] Sarkar | Terpene based sustainable methacrylate copolymer series by emulsion polymerization: Synthesis and structure-property relationship[END_REF] via emulsion polymerization. However, low yields were obtained.

Living anionic polymerization was utilized to design a hard/soft/hard triblock copolymer based on myrcene and α-methyl-p-methylstyrene (derived from limonene). [START_REF] Bolton | Sustainable Thermoplastic Elastomers from Terpene-Derived Monomers[END_REF] The resulting thermoplastic elastomer showed good microphase separation and displayed better mechanical properties (tensile strengths up to 10 MPa and elongation at break of 1300 %) than those of a traditional petroleum-based poly(styrene)-b-poly(isoprene)-b-poly(styrene). Hilschmann and Kali have reported the RAFT homopolymerization of myrcene using a trithiocarbonate based RAFT agent. [START_REF] Hilschmann | Bio-based polymyrcene with highly ordered structure via solvent free controlled radical polymerization[END_REF] Surprisingly, high regioselectivity was observed with > 96% of 1,4 addition.

Metafiot et al. have reported the synthesis of myrcene homopolymers and elastomeric block copolymers with styrene by nitroxide mediated polymerization. [START_REF] Metáfiot | Synthesis of β-Myrcene-Based Polymers and Styrene Block and Statistical Copolymers by SG1 Nitroxide-Mediated Controlled Radical Polymerization[END_REF] Reasonable control over the polymerization process was achieved, but the high entanglement molecular weight of the myrcene block resulted in brittle diblock copolymers.

Applications of terpene-based polymers

Available polyterpene resins are low molecular weight hydrocarbon like polymers used as adhesive components to impart tack (to both solvent-based and hotmelt systems), provide high gloss, good moisture vapor transmission resistance, good flexibility for wax coating and ensure viscosity control and increases the density to cast waxes. 23 Thakur and co-workers reported the application of poly(β-pinene) as semiconductive material. [START_REF] Vippa | Electrical and optical properties of a novel nonconjugated conductive polymer, poly(β-pinene)[END_REF] Upon doping poly(β-pinene) with iodine, the formed nonconjugated polymer became electrically conductive. The same authors also reported Chapter 1

16

that at high doping level of iodine, the non-conjugated polymer exhibited a large quadratic electro-optic effect that would be useful for non-linear optics application. [START_REF] Rajagopalan | Quadratic electro-optic effect in a nanooptical material based on the nonconjugated conductive polymer, poly(β-pinene)[END_REF]

Reversible deactivation radical polymerization (RDRP)

Free radical polymerization (FRP) is one of the major polymerization methods used for preparing high molecular weight polymers in both industrial and academic laboratories. Approximately 50 % of all commercial polymers are produced by radical polymerization. [START_REF] Zetterlund | Controlled/Living Radical Polymerization in Dispersed Systems[END_REF] This process exhibits tolerance to impurities and can be performed in bulk, solvent or dispersed system. Nevertheless, the major drawback of this process is that it is not possible to synthesize structurally advanced and well-defined macromolecular structures such as block copolymers or star polymers. In the free radical polymerization process, new chains are continually formed and terminated, with a lifetime of the active chain that spans from less than 1 second to 10 seconds. A consequence is that long chains are formed early in the process and in the absence of crosslinkers and chain transfer to polymer, the molecular weights decrease with monomer conversion due to the depletion of monomer (gel effect may lead to an increase of the molecular weight during the last stages of the process). In living ionic polymerization, all chains are initiated at the beginning of the reaction and continue growing until all the monomer is consumed. From this, the molecular weight increases linearly with conversion and the molecular weight distribution is narrow. However, ionic polymerizations are restricted to a limited number of monomers and use very exigent reaction conditions. RDRP processes combine the robustness of the radical polymerization with the control and precision offered by living anionic polymerization.

This has been achieved by using species that reversibly deactivate or terminate chains.

These species control the concentration of active propagating species by maintaining a majority of chains in a dormant form. In radical polymerization, the rate of radicalradical termination is proportional to the square of radical concentration (Rt ∝ [Pn•] 2 ).

Thus, the event of termination can be reduced relative to propagation (Rp ∝ [Pn•]) by reducing the radical concentration. Usually, the concentration of propagating radicals in reversible deactivation radical polymerization techniques (RDRP) is lower than in free radical polymerization. The RDRP techniques allow the facile production of welldefined polymers with good chain end fidelity and most importantly block copolymers.

In these processes, the reaction ideally proceeds until all monomer is consumed and may continue if more monomer is added. The concentration of active species remains constant in living polymerization, the molecular weight increases linearly with the conversion and the molecular weight distribution is narrow, which is not observed in Chapter 1 18 the free radical polymerization system. [START_REF] Moad | 9 -Living Radical Polymerization[END_REF] In practice, termination cannot be avoided and the ratio termination/propagation increases at high conversions. Nitroxide mediated polymerization (NMP), [START_REF] Hawker | New Polymer Synthesis by Nitroxide Mediated Living Radical Polymerizations[END_REF][START_REF] Nicolas | Nitroxide-mediated polymerization[END_REF] transition-metal mediated reversible deactivation polymerization (TMM-RDRP, ATRP) 32,[START_REF] Ouchi | Transition Metal-Catalyzed Living Radical Polymerization: Toward Perfection in Catalysis and Precision Polymer Synthesis[END_REF][START_REF] Matyjaszewski | Atom Transfer Radical Polymerization (ATRP): Current Status and Future Perspectives[END_REF] and reversible addition-fragmentation chain transfer (RAFT) polymerization [START_REF] Moad | Living Radical Polymerization by the RAFT Process -A Third Update[END_REF][START_REF] Gody | Pushing the Limit of the RAFT Process: Multiblock Copolymers by One-Pot Rapid Multiple Chain Extensions at Full Monomer Conversion[END_REF][START_REF] Barner-Kowollik | RAFTing down under: Tales of missing radicals, fancy architectures, and mysterious holes[END_REF] are the most often used RDRP techniques.

Reversible deactivation radical polymerization (RDRP) was initially developed in homogeneous systems (bulk and solution). However, the advantages of the polymerization in aqueous dispersed media in terms of easiness of the process and environmental impact have pushed RDPR towards polymerization in dispersed media.

One of the intrinsic features of polymerization in dispersed systems is the compartmentalization. There are two types of compartmentalization effects, which are the segregation effect and the confined effect. The segregation effect refers to two species located in separate particles being unable to react, and it is the reason that makes both the polymerization rate and molecular weights higher in the heterogeneous media than in homogeneous systems. The confined space effect refers to the fact that two species located in the same particle react at a higher rate in small particles than in large particles.

Nitroxide-Mediated Polymerization (NMP)

NMP is one of the RDRP technique based on the persistent radical effect (PRE).

The exploitation of alkoxyamines as polymerization initiators and the use of NMP to produce block and end-functional polymers was first described in a patent application by Salomon et al. in 1985. [START_REF] Solomon | Polymerization process and polymers produced thereby[END_REF] The activation-deactivation mechanism in NMP system is presented in Scheme 1.5, where kact and kdeact denote the rate coefficients for thermal dissociation of alkoxyamine (activation) and coupling (deactivation), respectively. P- A wide range of nitroxides and derived alkoxyamines has been synthesized aiming at providing good control over the polymerization of a broad range of monomers. As the control is determined by the values of kact and kdeact, and these coefficients depend on the structures of the nitroxide and the monomer, the development of the field has been largely driven by the search of nitroxide structures able to control a broad range of monomers. The investigation in the field has created a substantial body of knowledge about the effect of the substituents around the breakable C-ON bond. [START_REF] Moad | Alkoxyamine-Initiated Living Radical Polymerization: Factors Affecting Alkoxyamine Homolysis Rates[END_REF][START_REF] Marque | Factors Influencing the C-O-Bond Homolysis of Trialkylhydroxylamines[END_REF][START_REF] Marque | Factors Influencing the C-O Bond Homolysis of Alkoxyamines: Effects of H-Bonding and Polar Substituents[END_REF][START_REF] Fischer | Steric and Polar Effects of the Cyclic Nitroxyl Fragment on the C-ON Bond Homolysis Rate Constant[END_REF] It can be summarized that the stabilization of both propagating radical and the nitroxide favors the C-ON bond hemolysis (increase kdeact), [START_REF] Marque | Factors Influencing the C-O-Bond Homolysis of Trialkylhydroxylamines[END_REF][START_REF] Beaudoin | Alkoxyamine C-ON Bond Homolysis: Stereoelectronic Effects[END_REF] steric strain on both nitroxide and alkyl fragment also increase the kdeact, [START_REF] Bertin | Steric, and Stabilization Effects in Alkoxyamines C-ON Bond Homolysis: A Multiparameter Analysis[END_REF] high polar alkyl fragment of the alkoxyamine increase kdeact (kdeact decreases with increasing the polarity in the nitroxide fragment) [START_REF] Fischer | Steric and Polar Effects of the Cyclic Nitroxyl Fragment on the C-ON Bond Homolysis Rate Constant[END_REF] and the effect of the chain length depends on the nature of the propagating radical. 81 Nitroxide/alkoxyamines usually used in NMP process include 2,2,6,6tetramethyl-1-piperidinyloxy (TEMPO) , 75, 82-84 2,2,5-trimethyl-4-phenyl-3-azahexane-3-oxyl) (TIPNO), [START_REF] Nicolaÿ | Synthesis and Evaluation of a Functional, Water-and Organo-Soluble Nitroxide for "Living" Free Radical Polymerization[END_REF][START_REF] Marx | Synthesis and evaluation of a new polar, TIPNO type nitroxide for "living" free radical polymerization[END_REF] [START_REF] Simula | Nitroxide Mediated Polymerization[END_REF] summarized the monomers that can be polymerized under controlled condition (Table 1.2.). TEMPO, TIPNO and BlocBuilder/SG1 can regulate the polymerization of LAMs, acrylate and styrene but good control cannot achieve with methacrylates, except if a slight amount of styrene is used as comonomer. [START_REF] Benoit | Kinetics and Mechanism of Controlled Free-Radical Polymerization of Styrene and n-Butyl Acrylate in the Presence of an Acyclic β-Phosphonylated Nitroxide[END_REF][100][101][102] The termination events via disproportionation were typically observed, due to the unfavorable rate constants of activation and deactivation and the enhanced penultimate effect of the poly(MMA) macroradical. 103 This issue can be minimized by addition of small amount of comonomer. 104,105 The development of new nitroxide such as DPAIO could allowed the synthesis of polymethacrylates with good control and minimal undesired chains. [START_REF] Simula | Novel alkoxyamines for the successful controlled polymerization of styrene and methacrylates[END_REF]92,[START_REF] Ballard | Synthesis of poly(methyl methacrylate) and block copolymers by semi-batch nitroxide mediated polymerization[END_REF][START_REF] Ballard | Nitroxide mediated suspension polymerization of methacrylic monomers[END_REF][START_REF] Ballard | High solids content nitroxide mediated miniemulsion polymerization of n-butyl methacrylate[END_REF] Moreover, low fraction of disproportination was obtained during the polymerization of methyl methacrylate, which is not the case of the SG1. 92 Some control over the polymerization of butyl acrylate was also achieved. [START_REF] Simula | Nitroxide mediated copolymerization of acrylates, methacrylates and styrene: The importance of side reactions in the polymerization of acrylates[END_REF] It can be seen that the nitroxide/alkoxyamines that control the polymerization of methacrylates cannot control the polymerization of all MAMs or LAMs (Table 1.2.). The good control of the polymerization depends on the stability of the nitroxide radical, the terminations and the kact and kdeact values. As these parameters are different for each monomers, it is crucial to adapt the structure of the alkoxyamine to each monomers considered, which makes the existence of one universal alkoxyamine impossible.

N-tert-butyl-N-[1-diethylphosphono-(2,2-dimethylpropyl)] (SG1), 87, 88 N-(1-methyl-(1-(4-nitrophenoxy)carbonyl)ethoxy)-N-(1-methyl-(1-(4- nitrophenoxy)carbonyl)ethyl) benzeneamine (DPAIO)
Table 1.2. Nitroxides/alkoxyamines and monomer compatibility chart. [START_REF] Simula | Nitroxide Mediated Polymerization[END_REF] Emulsion polymerization has been used extensively to produce a wide range of speciality polymers. This process starts with a stirred mixture of water, initiator (usually water-soluble), monomer and emulsifier. Polymer particles are formed via micellar and/or homogeneous nucleation during interval Ι (0-10 % monomer conversion). During interval II (< 40 % monomer conversion), monomer droplets and monomer-swollen particles coexist, and monomer diffuses from droplet to particles as Chapter 1

24

the monomer is consumed in the particles by polymerization. In interval III (monomer conversion > 40 %), monomer droplets no longer exist, and the system consists of monomer-swollen particles in a continuous aqueous phase. [START_REF] Zetterlund | Controlled/Living Radical Polymerization in Dispersed Systems[END_REF]108 The NMP was performed in emulsion polymerization, but only a few works were successful. [START_REF] Zetterlund | Controlled/Living Radical Polymerization in Dispersed Systems[END_REF]109,110 The reason was that the stable free radicals used were rather water-insoluble and they could not diffuse fast enough from the monomer droplets to the particles, which reduced the control of the polymerization. This problem also affects the other RDRP processes.

For this reason, the miniemulsion polymerization is commonly used with RDRP system. Droplet nucleation in miniemulsion polymerization avoids the diffusional limitations found in conventional emulsion polymerization and allows the incorporation of the water-insoluble compounds to the reaction loci. In the miniemulsion polymerization process, the surfactant is dissolved in water, the costabilizer is dissolved in the monomers and mixed with the aqueous solution of surfactant under stirring. Then the mixture is subjected to high efficient homogenization, resulting in stable small monomer droplets. Once the initiator is added to the system, the radicals enter into the monomer droplets and become polymer particles. 111,112 The main alkoxyamine/nitroxides utilized in miniemulsion polymerization are TEMPO, SG1 and Dispolreg 007. TEMPO-based miniemulsion NMP of styrene has been carried out successfully for a number of different systems such as TEMPO/BPO, 113, 114 KPS/TEMPO 114,115 and PS-TEMPO. 116,117 Due to the low equilibrium constant of TEMPO/styrene, the polymerization is generally conducted at high temperature (> 120 ℃). In the case of the initiator/TEMPO system, their ratio is an essential parameter as if the initiator ratio is too high, the TEMPO is not present in enough quantity to ensure control/livingness. In addition, the hydrophobicity of the initiator is also important because the termination in the aqueous phase increases with increasing the concentration of water-soluble initiator. 115 Miniemulsion polymerization of styrene (120 ℃) and acrylates (112 ℃) controlled with an SG1-based alkoxyamines such as BlocBuilder, 118,119 or combination of SG1 with the radical source like AIBN or KPS at 90 ℃ have been reported. 118,120 However, in the case of any initiator, the molecular weight distributions are typically broad. Ballard et al [START_REF] Ballard | High solids content nitroxide mediated miniemulsion polymerization of n-butyl methacrylate[END_REF] have reported the NMP miniemulsion polymerization of butyl methacrylate at moderate temperatures (T = 90 ℃) using Dispolreg 007 as alkoxyamine. It was shown that high conversion and high solids content (52 %) with a reasonable control over the molecular weight could be obtained. More recently, the Dispolreg 007 was also utilized to polymerize methacrylic monomers via suspension polymerization. [START_REF] Ballard | Nitroxide mediated suspension polymerization of methacrylic monomers[END_REF] High conversion with high molecular weights (100,000 g.mol -1 ) were obtained. It also observed that under the same conditions the polymerization rate in suspension polymerization was faster than Chapter 1 26 bulk polymerization. This was related to the aqueous phase decomposition of nitroxide.

Moreover, the versatility of this alkoxyamine was tested to form a diblock copolymer with methyl methacrylate and benzyl methacrylate. reported the seed polymerization of styrene in emulsion polymerization using cumyl dithiobenzene as a RAFT agent, finding that due to the limited transport of the RAFT agent from monomer droplets to polymer particles, a broad molecular weight distribution was obtained. Miniemulsion polymerization avoids transport issues and has been utilized with a wide range of monomers such as styrene, 125-128 n-butyl acrylate, 129-131 methyl methacrylate, 132-134 n-butyl methacrylate, 125,129,133 as well as to synthesize di/tri-block copolymers. 130,132,135 A problem that often appeared in the early literature was the lack of the colloidal stability of the system during the miniemulsion polymerization. 125,133 In an attempt to shed light on this issue, polymerization. In addition, to linear multiblock copolymer, these methods can be utilized to create complex polymer architectures such as comb and star copolymers. 138 Because of the interaction between the different blocks, block copolymers selfassemble into organized microdomain structures. AB diblock copolymers can form a variety of morphologies in the melt as well as in solution (Figure 1.5). 139 lamellae structure is formed. In the composition range between cylinders and lamellae structures, a complex bi-continuous cubic double gyroid is formed.

The parameters controlling the block copolymer segregation are the interaction parameter between polymer A and B (χAB that provides the driving force for the phase separation) and the total degree of polymerization (N). A strong segregation between the blocks occur when χN >> 10 (strong segregation limit, SSL), whereas separation is only partial when χN < 10 (weak segregation limit, WSL). In Chapter 6, the most relevant conclusions of this Thesis are presented.

A detailed description of the main experimental procedures and characterization techniques is presented in Appendices I and II.

Introduction

Terpene is an abundant bio-based monomer that contains one or more unsaturated carbons. The most representative and viable source of terpenes are the turpentine resins extracted from coniferous trees and citric fruits. Terpenes are commonly utilized in fragrance and flavors formulations (e.g. limonene, camphor).

Attempts to form polymers by direct polymerization of terpenes have been reported. 1 However, the results obtained show that the terpenes do not easily polymerize and only low molecular weight could be obtained working at low temperature via cationic polymerization. [2][3][4][5][6][7] Moreover, the copolymerization of the terpenes with several commercial monomers via free radical polymerization led to low incorporation of the terpene compound due to the low reactivity ratio. [8][9][10][11][12] A more convenient approach to incorporate terpenes by free radical polymerization was introduced by Tang et al. 13

Experimental

Materials

The materials are given in Appendix I

Synthesis procedures

Synthesis of tetrahydrogeraniol acrylate (THGA)

and tetrahydrogeraniol methacrylate (THGMA)

Tetrahydrogeraniol (THG) Cyclademol (CDM)
Chapter 2 70

Method A: Esterification with acryloyl chloride THGA was first prepared by esterification of tetrahydrogeraniol with acryloyl chloride. Tetrahydrogeraniol (9.50 g, 0.06 mol), triethylamine (6.07 g, 0.06 mol) and dichloromethane (180 mL) were added to a three-neck 500 mL round-bottom flask (RBF) equipped with rubber seals, dropping funnel and a magnetic stirrer. The mixture was placed in an ice bath and left under stirring for 2 hours. Subsequently, acryloyl chloride (8.14 g, 0.09 mol) was added dropwise via the dropping funnel. Upon complete addition, the mixture was left under stirring for 30 minutes in the ice bath and for 24 hours at ambient temperature. Then, the mixture was filtered and the mixture was washed several times with brine and deionized water. The organic phase was passed through basic alumina column and the volatiles were removed by rotary evaporation to yield a transparent viscous liquid.

Scheme 2.1. Reaction scheme to synthesize the THGA by method A.

Method B: Esterification with acrylic acid or methacrylic acid.

Esterification of THG with acids was also tried aiming at both THGA and THGMA. Tetrahydrogeraniol (28.5 g, 0.18 mol), acrylic acid (21.84 g, 0.30 mol) or methacrylic acid (25.81 g, 0.30 mol), 2-methyltetrahydrofuran (250 mL), propylphosphonic anhydride (57 g, 0.18 mol) and triethylamine (16 g, 0.164 mol) were mixed in a 500 mL round bottom flask and stirred at room temperature for 24 hours.

Then, water was added and the aqueous phase extracted with diethyl ether. Afterwards, the mixture was washed several times with brine and deionized water. The organic phase was passed through basic alumina column and the volatile solvent was removed by rotary evaporation to yield a transparent viscous liquid.

Chapter 2 72 Scheme 2.2. Reaction scheme to synthesize THGA and THGMA by method B.

Synthesis of cyclademol acrylate (CDMA) and cyclademol methacrylate (CDMMA)

Method B: Esterification with acrylic acid or methacrylic acid.

A mixture of cyclademol (28.12 g, 0.18 mol), acrylic acid (21.84 g, 0.30 mol)

or methacrylic acid (25.81 g, 0.30 mol), 2-methyltetrahydrofuran (250 mL), propylphosphonic anhydride (57 g, 0.18 mol) and triethylamine (16 g, 0.164 mol) were mixed in a 500 mL round bottom flask and stirred at room temperature for 24 hours.

The water was added and the aqueous phase extracted with diethyl ether. Then, the mixture was washed several times with brine and deionized water. The organic phase was passed through basic alumina and the volatile solvent was removed by rotary evaporation to yield a transparent viscous liquid.

Scheme 2.3. Reaction scheme to synthesize the CDMA and CDMMA by method B.

Characterization

The monomer was characterized by 1 H NMR (CDCl3, 400 MHz) and 13 C NMR (CDCl3, 100 MHz).

Results and discussion

The presence of the hydroxyl group on the renewable starting material was utilized to incorporate a (meth)acrylate functionality. In this work, tetrahydrogeaniol acrylate (THGA), tetrahydrogeraniol methacrylate (THGMA), cyclademol acrylate (CDMA) and cyclademol methacrylate (CDMMA) were synthesized. The preparation of the tetrahydrogeraniol meth(acrylate) monomer was first carried out by (meth)acylation with (meth)acryloyl chloride (Scheme 2.1). The success of the reaction was confirmed by 1 H and 13 C NMRs. Figure 2.2 shows the 1 H and 13 C NMR spectra of the THGA monomer. It can be seen that, the NMR results provided the signal at 6.38, 6.12 and 5.80 ppm, which correspond to the protons of methylene and vinyl groups.

The characteristic peaks are assigned, as follow: 6. It should be noted that, this route provided high yield (~ 85%, Table 2.1) of the synthesized THGA monomer. However, we recognise that this synthetic route is not sustainable or green. Therefore, the hunt for a more sustainable system prompted us to explore new synthetic approaches which are more environmentally friendly. For this, we used (meth)acrylic acid and T3P ® as catalyst, which avoids the use of chlorinated

(d) (s, O-CH2-CH2-CH2), 1.69 (k) (m, 1H, (CH3)2-CH-CH2), 1.50 (e) (m, 2H, CH-CH2-CH2-O), 1.47 (f) (m, 1H, CH3-CH-CH2- CH2), 1.28 (i) (m, 2H, CH-CH2-CH2-CH2-CH), 1.14 (h, j) (m, 4H, CH-CH2-CH2-CH2- CH), 0.91 (g) (d, 3H, CH3-CH-CH2-CH2), 0.89 (l) (d, 6H, (CH3)2-CH-CH2-CH2).
THGMA monomer; 6.12 (a) (m, 1H, CH2=CH-C=O), 5.56 (b) (p, 1H, CH2=C- The yield of the final product is presented in Table 2.1. It can be seen that high yield of terpene methacrylates (THGMA and CDMA) was achieved, while moderate yield of terpene acrylates was obtained.

(CH3)(C=O), 4.21 (d) (ddt, 2H, O=C-O-CH2), 1.96 (c) (t, 3H, CH2=C-CH3), 1.73 (k) (ddt, 1H, (CH3)2-CH-CH2), 1.55 (e) (m, 2H, CH-CH2-CH2-O), 1.54 (f) (m, 1H, CH3- CH-CH2), 1.31 (i) (m, 2H,CH2-CH2-CH2-CH), 1.18 (h) (m, 2H, CH2-CH2-CH2-CH), 1.18 (J) (m, 2H, CH2-CH2-CH2-CH), 0.92 (g) (dd, 3H, CH3-CH-CH2-CH2), 0.91 (l) (dd, 6H, (CH3)2-CH-CH2-CH2). CDMA monomer; 6.36 (a) (dd, 1H, O=C-CH=CH2), 6.09 (c) (ddd, 1H, O=C- CH=CH2), 5.8 (b) (dd, 1H, O=C-CH=CH2), 4.74 (d) (m, 1H, CH-O-C=O), 1.64 (f) (m, Monomer Synthesis 77 1H, CH-CH-O-C=O), 1.44-1.33 (h,k,m) (m, 4H, CH2-CH2-CH2-CH(CH2-C)-CH-O- C=O), 1.18 (d, 4H (e,i), CH2-CH2-CH-CH(CH3)-O-C=O), 1.05 (g,j) (m, 2H, CH2- CH2-CH2-CH-CH(CH3)-O-C=O), 0.9 (l) (m, 1H, CH(CH2-C)-CH-O-C=O), 0.85 (m, 6H (n), C(CH3)2) CDMMA monomer; 6.1 (a) (s,1H, O=C-C(CH3)=CH2), 5.5 (b) (s,1H, O=C- C(CH3)=CH2), 4.7 (d) (m, 1H, CH-O-C=O), 1.95 (c,f) (s, 4H, CH-CH-O-C-C(CH3)), 1.5 (h, k, m) (m, 4H, CH2-CH2-CH2-CH(CH2-C)-CH-O-C=O), 1.2 (e, i) (m, 4H, CH2- CH2-CH-CH(CH3)-O-C=O), 1.05 (j, g) (m, 2H, CH2-CH2-CH2-CH-CH(CH3)-O- C=O), 0.95 (l) (s, 1H, CH(CH2-C)-CH-O-C=O), 0.9 (n) (s, 6H, C(CH3)2).

Conclusions

The (meth)acrylate moieties capable of undergoing by free radical polymerization were successfully incorporated into the terpene derivatives (tetrahydrogeraniol (THG) and cyclademol (CDM)) by following two different approaches, esterification with acryloyl chloride and with (meth)acrylic acids. THGA, THGMA, CDMA and CDMMA were successfully synthesized by esterification with (meth)acrylic acid, which is greener than the acryloyl method. Furthermore, the presence of the reactive vinyl bond was confirmed by 1 H NMR spectroscopy. High This soft/hard/soft triblock copolymer was further analyzed by thermal analysis and AFM imaging, thus highlighting a phase separation between soft and hard phases.

Experimental

Materials

The materials are given in Appendix Ι

Synthesis procedures

Free radical polymerization of THGA

Renewable terpene derivative as a bio-sourced elastomeric building block in the design of functional acrylic copolymers 87

The free radical polymerization of THGA was performed at various monomer concentrations in toluene, [M]0 = 0.6, 1.8, 3.6 mol.L -1 and in bulk (Table 3.1, entries 1-4). In the experiments, 2.50 g of THGA (1.18 x 10 -2 mol) and the amount of toluene needed to obtain the desired monomer concentration were placed into a 25 mL RBF equipped with rubber seals and a magnetic stirring bar. The mixture was deoxygenated for 30 minutes with purging nitrogen and subsequently placed into an oil bath at 80 °C.

Then, AIBN (AIBN/THGA about 1.94 x 10 -3 mol/mol) dissolved in a small amount of toluene was added as a shot via a deoxygenated syringe to initiate the polymerization.

Polymerization was carried out under stirring for 7 hours at 80 °C and samples were carefully taken via a deoxygenated syringe.

RAFT polymerization of THGA

The RAFT polymerization of THGA was also performed at various monomer concentrations in toluene, [M]0 = 0.6, 1.8, 3.6 mol.L -1 and in bulk; using a ratio [DBTTC]0/[I]0

1 0.6 - 1.23×10 -3 - 2 1.8 - 3.50×10 -3 - 3 3.6 - 6.88×10 -3 - 4 bulk - 9.45×10 -3 - 5 0.6 2.47×10 -3 1.23×10 -3 2 6 1.8 7.03×10 -3 3.50×10 -3

Characterization

Monomer conversion was calculated from 1 H NMR (CDCl3, 400 MHz), the information is given in Appendix Ι.

The theoretical molar masses were calculated using equations 1 and 2, the information is given in Appendix Ι. 3.3, entries 5 to 12.

Results and discussion

Renewable terpene derivative as a bio-sourced elastomeric building block in the design of functional acrylic copolymers 97 Renewable terpene derivative as a bio-sourced elastomeric building block in the design of functional acrylic copolymers 99 Similar to the free radical polymerizations, higher initial monomer concentration

[M]0 resulted in higher rate of polymerization (see Table 3.2). In the case of 3.3 and Figure 3.4). However, in the case of 0.6 and 1.8 mol.L -1 , the experimental molar masses were lower than the predicted values (Table 3. Renewable terpene derivative as a bio-sourced elastomeric building block in the design of functional acrylic copolymers 101

In Figure 3.4B it can be seen that the evolution of 𝑀 ̅ n as a function of monomer conversion at low monomer concentration (0.6 and 1.8 mol.L -1 ) deviates from linearity at higher conversions, while at higher monomer concentrations molar mass evolves linearly throughout the whole conversion range. This might be due to the occurrence of undesired chain transfer to solvent reactions, as well as chain transfer to polymer reactions which introduces the presence of mid-chain radical (MCRs). Both intramolecular (also referred to as backbiting) and intermolecular chain transfer reactions are relatively common in acrylic polymerization, with intramolecular transfer being the predominant pathway. 1,3,4 The presence of MCRs in the polymer chains can yield the formation of branches and/or the formation of macromonomers (bearing ωvinyl functionalities) and initiating radicals through β-scission, although both reactions typically only begin to become significant at high temperatures. 1,[5][6][7] The presence of branching has relatively limited effect on the molecular weight distribution, but βscission creates new chains leading to both a decrease in 𝑀 ̅ n as well as a broadening of the dispersity. 8,9 It has previously been shown that this leads to a dramatic decrease in 𝑀 ̅ n at high conversions as it is observed for the reaction in Figure 3.4B. 8,9 In order to determine if this effect is indeed important in the polymerization of THGA at lower monomer concentrations, the presence of intramolecular transfer to Chapter 3 102 polymer reactions was checked by NMR though the presence of quartenary carbons (Cq) by 13 C NMR and the presence of macromonomer formation in 1 H NMR. An example for the reaction of THGA at 80 °C with [M]0 = 1.8 mol.L -1 (entry 9) is shown in Figure 3.5. It can be observed that the branching content at 91 % conversion was around 2.70 %. It should be noted that this branching content is significantly higher than that expected for typical acrylic monomers at similar temperatures. 2,10,[START_REF] Sarkar | Terpene based sustainable methacrylate copolymer series by emulsion polymerization: Synthesis and structure-property relationship[END_REF] For example at this reaction temperature and conversion, n-butyl acrylate would be expected to have a degree of branching of less than 1 %. 11 /ppm

% Conversion 2.70 % Branching

Renewable terpene derivative as a bio-sourced elastomeric building block in the design of functional acrylic copolymers 103 Moreover, the presence of unsaturated carbon from the β-scission formation is confirmed by 1 H NMR (Figure 3.6), with a percentage of macromonomers of 0.12 % at 91 % conversion. The effect that this concentration of macromonomer can have on the evolution of 𝑀 ̅ n can be determined by estimating the number of chains generated by β-scission relative to that of the RAFT agent. In this way, the theoretical DPn at 91% conversion based only of RAFT agent derived chains is 228 (≈48,000 g.mol -1 ), but taking into account the effects of β-scission this decreases to 179 (≈38,000 g.mol -1 ), which is in rough agreement with the experimentally determined molar mass (see Table 3.3). It should be noted that, in agreement with previous work which has suggested that under conditions of RDRP the amount of branching is significantly reduced, 12 3.8A it can be observed that at lower target degree of polymerization, the rate of polymerization was significantly lower despite having high concentration of initiator. This may be attributed to some retardation caused by the RAFT process itself as has been extensively reported in literature. [13][14][15][16][17][18] More importantly, in Figures 3.8B and 3.8C, it can be seen that in all cases excellent agreement between the theoretical and experimental 𝑀 ̅ n was achieved and narrow molar mass distributions were obtained, even up to high conversion. This demonstrates that under the correct reaction conditions (high concentration of THGA), good control over the polymerization of THGA can be achieved at molar masses targeting the range 5,000-100,000 g.mol -1 .

Renewable terpene derivative as a bio-sourced elastomeric building block in the design of functional acrylic copolymers 107 3.3).

Triblock copolymers

The main advantage of a RDRP process is that the retention of end group fidelity allows the preparation of block copolymers. We aimed to exploit the "livingness" of the RAFT polymerization of poly(THGA) to prepare a soft-hard-soft ABA triblock copolymer, using poly(styrene) as the "hard" phase (see Scheme 1 for details). To this end, a poly(THGA) macro-RAFT agent was prepared at 80 °C for 8 hours, using an [S]/[macro-RAFT] = 500) was added to the purified macro-RAFT agent in the presence of AIBN to re-initiate polymerization at 80 °C. In Figure 3.9, the success of the chain extension is evidenced by SEC, with the MMD clearly shifting to higher molar masses (89 % conversion, 𝑀 ̅ n = 68,000 g.mol -1 ). A monomodal distribution is obtained for the ABA triblock copolymer with low dispersity value (Ð = 1.15). The slight increase in dispersity value during the chain extension is primarily attributed to the polymerization of the less activated monomer styrene with an active macro-RAFT agent, which yielded to a non-optimum addition-fragmentation process. 19,20 In addition, the broadening of the MMD might also be due to the small presence of dead chains (i.e. not bearing a trithiocarbonate group) during the formation of the macro-RAFT agent.

Renewable terpene derivative as a bio-sourced elastomeric building block in the design of functional acrylic copolymers 109 The successful syntheses of homopoly(THGA) and thermoplastic elastomers made out of soft/hard/soft and hard/soft/hard triblock copolymers of THGA and styrene were described in Chapter 3. However, the polymerization was carried out in solution, namely with an extensive use of solvent. In order to overcome this problem, miniemulsion polymerization is used in this chapter. In addition, as polyTHGA presents a low Tg, its use as pressure sensitive adhesive is explored.

Pressure sensitive adhesives (PSAs) are important polymer materials, with a global revenue estimated to USD 6 billion in 2017 (and a substantial growth is expected Chapter 4 122 in the next years). 1 Efforts to improve the sustainability of those materials by the substitution of some petroleum-based chemicals to bio-based alternatives have been reported. 2,3 Thus, for polymers synthesized by step growth polymerization, diols and diacids derived from renewable precursors served as monomers for the synthesis of robust PSAs. 4,3 Also, lactide and menthide have been used as building blocks for the synthesis of nanostructured PSAs via ring-opening polymerization. [5][6][7][8][9] Although step growth polymers serve in some niche applications, polyacrylates produced by free radical polymerization dominate the PSA market. 1 Typically, acrylic based PSAs are random copolymers that contain relatively long chain acrylates (e.g. 2ethylhexyl acrylate, n-butyl acrylate) as soft monomers, whereas styrene or methyl methacrylate are commonly utilized as hard monomers. 10 Therefore, search for renewable substitutes is an active field. 2,3,11 Block copolymers are an interesting alternative to random copolymers because their mechanical properties can be tailor-made by modifying the functionality and the length of the blocks. [12][13][14][15] In addition, the synthesis of this type of copolymers is readily available by controlled radical polymerization. 13 It is then not surprising that attempts to synthesize PSAs using bio-based monomers have been made and PSAs with good Paving the way to sustainable waterborne pressure-sensitive adhesives using terpenebased triblock-copolymer 123 mechanical and adhesion properties have been reported. 2,[6][7][8][9]11 Thus, triblock PSAs were prepared using bio-based acrylic isosorbide (AAI) and glucose acrylate tetraacetate as hard monomers and 2-ethylhexyl acrylate (2-EHA) or n-butyl acrylate (BA) as the "soft" monomer. 9,16 Acrylic monomers obtained from depolymerization of lignocellusolic biomass have also used as hard monomers in combination to conventional soft acrylic monomers to produce partially bio-based PSAs. 17 These reports show that block copolymer PSAs in which the petroleum-based monomers are partially substituted give interesting mechanical and adhesion properties. However, a close look to the synthetic methods used reveals that these materials are produced in harmful solvent, e.g. toxic DMF. 9,16,18 In addition, the sustainability and scalability of the process are compromised by the purification step used after the formation of the first block. Consequently, there is a need to go further in the synthesis of PSAs, by designing a process that promotes the use of renewable resources and that has a lower environmental impact.

Preparation of the miniemulsion

Miniemulsion polymerization is a versatile method that allows the synthesis of a broad range of waterborne dispersions. [22][23][24] Typically, the organic phase consisted of an homogeneous mixture of monomer (THGA or CDMA, 10 to 25 g), RAFT agent . 22 After mixing the two phases and stirring for 30 minutes, the pre-emulsion was sonicated at 80 % output and 0.8 duty cycle for 10 minutes, in an ice bath to avoid overheating and under magnetic stirring, yielding a stable miniemulsion. The resulting mean droplet sizes for each polymerization are summarized in Table 4.2.

Paving the way to sustainable waterborne pressure-sensitive adhesives using terpenebased triblock-copolymer 127

RAFT miniemulsion polymerization

The miniemulsion was placed into a 250 mL round-bottom flask (RBF) equipped with a rubber seal and a magnetic stirring bar and subsequently deoxygenated with purging nitrogen for 30 minutes. The polymerization was carried out by placing the mixture in an oil bath at 70 °C for 7 hours under stirring. In this work, three different initiators were used (AIBN, KPS and THBP/AsAc, with a ratio [DBTTC]0/[I2]0 = 10).

AIBN was dissolved directly into the organic phase prior to the miniemulsification. In contrast, KPS (dissolved in water) was added as a single shot to the reaction mixture at Paving the way to sustainable waterborne pressure-sensitive adhesives using terpenebased triblock-copolymer having benign toxicity and easily removable as shown in the industrial production of polyurethane dispersions. 25 The reaction mixture was then placed in an oil bath at 70°C and left to polymerize for 8 h (by this point all the acetone was removed). After polymerization, the reaction was cooled to room temperature.

Characterization

The monomer conversion was calculated using equation 1, the information is given in Appendix Ι.

The theoretical molar masses were calculated using equation 2, the information is given in Appendix Ι. was also tested. This redox couple yields hydrophobic radicals in the aqueous phase that are readily incorporated into the monomer droplets, 26 and it has shown great potential in RAFT polymerization in solution and in free radical polymerization in dispersed media. 27,28 In Figure 4.2A, it becomes clear that the more hydrophobic initiators yielded higher monomer conversions (> 90 %). Conversely, only 60 % monomer conversion could be achieved with KPS in 6 hours. This arises from the relative difference in hydrophobicity between initiating radicals and monomers. THGA is highly hydrophobic and hence its concentration in the aqueous phase was low. As a consequence the sulfate radicals generated from KPS did not find enough monomer to propagate and as they are too hydrophilic to directly enter into the monomer droplets, they underwent severe termination in the aqueous phase. This resulted in an inneficient initiation of the droplets. The use of the TBHP/AscA redox couple allowed for a rapid polymerization (> 90 % conversion in 1 hour), due to the fast generation of radicals upon the feeding of the oxidant (TBHP). Despite the advantages that the use of this efficient redox couple can provide, we decided to utilize AIBN as an hydrophobic initiator for further reactions, due to the simplicity of the reaction set-up. Chapter 3 and this is key to reduce the negative effect of side reactions such as intramolecular chain transfer to polymer (also referred to as backbitting). 21,29 Backbitting is typical in the polymerization of acrylates and leads to the formation of mid-chain radicals (MCRs), which after β-scission yields new radicals and macromonomers, 30,31 which affect the values of Mn at high monomer conversions (due to the creation of new chains). 32,33 It should be noted that the dispersity values observed herein (Đ < 1.2, Figure 4.2D) are comparable to that of the RAFT polymerization of THGA in solution (Chapter 3 and reference 21).

Results and discussion

Paving the way to sustainable waterborne pressure-sensitive adhesives using terpenebased triblock-copolymer 135

The effect of targeted degree of polymerization

The good level of control attained at relatively low molar masses (DPn = 50, Mn = 9,400 g.mol -1 ) encourages us to push the polymerization system further, by targeting different degrees of polymerization (250, 350 and 450). In all cases, high monomer DPn was close to that of the free radical polymerization. A similar behavior has been previously observed when the RAFT polymerization of THGA was conducted in solution (Chapter 3 and reference 21). That phenomenon was attributed to a rate retardation due to the RAFT process. [34][35][36] Finally, it should be noted that the overall rate of polymerizations in miniemulsion at 70 ºC are comparable to that of polymerization in solution at 80 ºC, 21 likely as a result of a compartmentalization effect. 24,37 In Figure 4.3B, the droplet/particle size increased as a function of targeted DPn, which may be the result of an enhanced stabilization at high concentration of the hydrophobic RAFT agent that is highly hydrophobic and may behave as a costabilizer. 38 In Figure 4.3C, it can be observed that good control over the RAFT process can be achieved. Thus, the values of observed molar masses increased linearly as a function of increasing monomer conversion, for all targeted DPns. Moreover, the observed values of molar masses were close to theory as depicted in Table 4.2, thus suggesting a minimum presence of side reactions. Finally, the polymers were obtained with relatively low dispersity values (Đ < 1.3, Figure 4.3D).

Paving the way to sustainable waterborne pressure-sensitive adhesives using terpenebased triblock-copolymer 137 , where [M]0, [CTA]0, [I]0 are the initial concentrations of monomer, chain transfer agent (CTA) and initiator respectively; MM, MCTA the molar masses (in g.mol -1 ) of the monomer and CTA respectively and p the monomer conversion at a time t (in seconds); f the initiator initiation efficiency f = 0.5 and assuming termination by combination only (fC = 1) and 𝑘 𝐷 𝐴𝐼𝐵𝑁 = 4.47 × 10 15 × 𝑒 -𝐸𝑎/𝑅𝑇 (𝑠 -1 ). 39, 40 c Extracted from SEC-MALS analysis using the measured dn/dc value for poly(THGA) (dn/dc = 0.0678 mL.g -1 ).

Paving the way to sustainable waterborne pressure-sensitive adhesives using terpenebased triblock-copolymer 139

Triblock copolymers

The focus of this chapter is to demonstrate the possibility of synthesizing complete bio-sourced terpene-based triblock copolymers to yield waterborne adhesives without the need of any intermediate purification step. Hence, it was of upmost importance to check that such triblock could be synthesized. Upon formation of a macro-RAFT agent in miniemulsion, one can exploit the effect of compartmentalization and enhanced "livingness" of the process (i.e. the number of polymer chains able to re-initiate polymerization) to produce block copolymers upon addition of the second monomer. 13,41 More specifically, the "soft" phase was composed of poly(THGA) (Tg ~ -46 ºC), whilst the "hard" phase consisted of poly(CDMA) (Tg ~ 88 ºC). Two types of structures were targeted, namely soft-hard-soft and hard-soft-hard triblocks. The triblock copolymers prepared are given in Table 4.3. It should be noted that for the sake of comparison, a triblock soft-hard-soft copolymer using styrene as hard block was also synthesized, with comparable weight percentages of soft and hard phases. Paving the way to sustainable waterborne pressure-sensitive adhesives using terpenebased triblock-copolymer 143 4.4), which will impact the mechanical properties of the final adhesive. 12,[START_REF] Ballard | Impact of Competitive Processes on Controlled Radical Polymerization[END_REF] Chapter 4 146

Adhesive properties of triblock copolymers

The adhesive properties of the waterborne triblock copolymer were determined.

It is worth to point out that no attempt to optimize the adhesive properties of these PSAs was carried out as the main goal of this work is to demonstrate that the synthesis of these bio-sourced materials under industrially implementable conditions was possible.

In order to determine the adhesive properties, the dispersions were casted onto a PET substrate. Upon careful drying, a transparent and homogeneous polymer film was obtained (Figure 4.6). Peel strength (180º peel), tack and shear resistance were determined as described in the experimental section and the values summarized in Table 4.5. This table shows that modification of the bio-sourced PSA structure (soft-hard-soft vs. hard-soft-hard)

and length of the blocks led to widely different adhesive properties. A cohesive failure is typical for PSAs based on triblock copolymers, due to the absence of crosslinking points that increase the cohesive strength of the adhesive. 9,12,16 In order to compare the performance of the fully bio-sourced PSAs, a soft-hardsoft PSA having similar structure and molecular weights, but using styrene instead CDMA was synthesized. The adhesives properties of this PSA are also given in Table Chapter 4 148 4.5. It can be seen that the bio-sourced PSA had better peel and shear resistances. It must be stressed that this result does not mean that the bio-resourced PSAs have a superior performance, because none of the PSA formulations was optimized. Besides, changes in the chain length strongly affect adhesion. 10 It might be the case herein that for varying block lengths, the non-fully bio-sourced PSAs outperformed the bio-based ones. Nevertheless, the key aspect of these results is that bio-sourced PSAs synthesized by a sustainable and industrially implementable process can compete in performance with regular PSAs. Finally, it should be stated that the adhesive properties could be improved further, by playing with the percentages of soft and hard phases and the presence of additives (e.g. tackifiers and/or plasticizers) 10 .

Paving the way to sustainable waterborne pressure-sensitive adhesives using terpenebased triblock-copolymer 149

Conclusions

In conclusion, the investigations conducted herein show that through the synthesis of terpene-based triblock copolymers it is possible to obtain waterborne pressure-sensitive adhesives in an industrially scalable manner with minimal environmental impact. The copolymers are synthesized by RAFT miniemulsion polymerization, as a more sustainable alternative to existing synthetic strategies relying on solvent-borne or bulk processes. The process is readily scalable as no intermediate purification step of the first block is needed. In addition, the yielded hard-soft-hard or soft-hard-soft triblock copolymers structures solely consist of terpene derivatives namely poly(tetrahydrogeraniol acrylate) and poly(cyclademol acrylate), thus maximizing the use of renewable resources. The phase-separating copolymers show interesting rheological behaviors, with the organization of the blocks (e.g. hard-softhard and soft-hard-soft) and their relative weight percentages influencing the values of Tgs, G' and G''. Finally, the resulting formulations show good mechanical properties and adhesives performances, which are comparable to that of a partially petroleumbased system. It is our hope that the relative ease of monomer synthesis and polymerization in aqueous dispersed media presented herein will serve as a building Chapter 4 150 stone for the development and industrialization of more sustainable pressure-sensitive adhesives.

*The fruitful discussions with Prof. Costantino Creton on the adhesive properties of the block copolymers synthesized in this chapter are acknowledged.

159

Chapter 5. Nitroxide mediated miniemulsion polymerization of using terpene methacrylates*

Introduction

Most synthetic plastics are derived from fossil fuel and their production increases every year. As a consequence, fossil resources are being exploited faster than they are being replenished, the price of oil and its derived products escalates, and hazardous materials are being released in large quantities into environment. [1][2][3][4] Therefore, the environmental concerns and the depletion of petroleum oil have promoted the search for greener plastics using (i) raw materials derived from natural renewable sources and (ii) more environmentally friendly polymerization processes.

An answer to the first point is the development of bio-based monomers for the production of various polymer matrices. [5][6][7] However, achieving the mechanical, thermal, electrical, rheological, and other physical properties required for commercial Chapter 5 160 applications is challenging. Therefore, the use of bio-resources for the synthesis of polymers is subjected to intensive research. This PhD is an attempt to contribute to this field using monomers derived from terpenes that area side product of the local paper including based on the "Landes" pine forest in the South West of France. The synthesis of the monomers is described in Chapter 2 and Chapters 3 and 4 are devoted to the polymerization of the terpene acrylates. An answer to the second point is the polymerization in aqueous dispersed system. This technique has shown several advantages compare to the synthesis in solution, especially in term of the environmentally friendly process, cost and controlling the heat transfer. 8 Reversible deactivation radical polymerization (RDRP) has been extensively researched during the past decades and several techniques have been developed. The most often used are nitroxide-mediated polymerization (NMP), [9][10][11] reversible additionfragmentation chain transfer polymerization (RAFT) 12 and transition metal-mediated radical polymerization (TMM-RDRP that includes atom transfer radical polymerization, ATRP) [13][14][15] . In spite of the intensive research the industrial implementation has been modest 16,17 mainly because none of these techniques completely fulfils the requirements for industrial production. RAFT and ATRP are able to polymerize a wide range of polymers, but they present problems of odour (RAFT)

Nitroxide mediated miniemulsion polymerization of using terpene methacrylate 161 coloring (RAFT and ATRP) and catalyst residues (copper in ATRP). Although extensive efforts have been undertaken in the past decade towards the removal of RAFT agents, post-polymerization modification and reducing copper catalyst content 18,19 the problem has not been solved yet. Although the polymers produced by NMP are not affected by this problem as they require no or minimal purification, there is no a general nitroxide able to control the polymerization of different monomer families. 20 Basically the nitroxides that control the polymerization of styrene and acrylates (BlocBuilder-SG1 21,22 and TIPNO 23 fail with methacrylates, whereas those able to control the polymerization of methacrylates (e.g. DPAIO and derivatives) are not successful for acrylates and/or styrene. 24,25 A hurdle that affects all the RDRP techniques is the cost associated to the control agent. As each polymer chain contains a molecule of the control agent and typically RDRP aims at producing polymers with a relatively low molecular weight (often for their use as additives) the cost due to the control agent is substantial.

Recently, Ballard et al have introduced new alkoxyamine (3-(((2-cyanopropan- 2-yl)oxy)(cyclohexyl)amino)-2,2-dimethyl-3-phenylpropanenitrile, Dispolreg 007)
that can be easily synthesized by a cost-effective process and it is able to mediate the polymerization of methyl methacrylate and styrene 26,27 and up to some extent that of acrylates 28 . Moreover, this alkoxyamine could be utilized to synthesize the block Chapter 5 162 copolymer in batch and semicontinuous reactors in both solution and dispersed media. [29][30][31] This chapter explores the possibility of synthesizing block copolymers from bio-sourced terpene-based methacrylates by nitroxide mediated miniemulsion polymerization. The formulation is adapted for the application as pressure sensitive adhesives (PSAs). This work complements Chapter 4 as diblock copolymers instead of triblock copolymers are obtained and a more-friendly and economically effective control agent (Dispolreg 007) is used. On the other hand, the requirement of easy scalability by avoiding any intermediate purification step is maintained.

Soft (tetrahydrogeraniol methacrylate monomer, THGMA, Tg = -30 ºC) and hard (cyclademol methacrylate, CDMMA, Tg = 92 ºC) were synthesized in Chapter 2.

First, in order to optimize the polymerization, THGMA was polymerized via NMP in toluene in the presence of the alkoxyamine Dispolreg 007. The effect of the reaction temperature and the possibility to control different degrees of polymerization were studied. Then, still in toluene (Scheme 5.1), the retention of active chain ends was tested by chain extension with cyclademol methacrylate (CDMMA). The phase separation of the diblock soft-hard copolymer obtained was observed by atomic force microscopy (AFM). After that, miniemulsion NMP of THGMA was studied aiming at obtaining a

Experimental

Materials

The materials are given in Appendix Ι

Synthesis procedures

NMP of THGMA in toluene

The NMP polymerization of THGMA in toluene was performed using . c Extracted from SEC-MALS analysis using the measured dn/dc value for poly(THGMA) (dn/dc = 0.056 mL.g -1 )

Chapter 5 166

Chain extension of Poly(THGMA) to yield a soft/hard diblock copolymers in toluene

A poly(THGMA) macro-initiator ([M]0/[Dispolreg 007]0 = 100, Mn,th = 23,000 g.mol -1 ) was first prepared in toluene via NMP as described above and the reaction was stopped at 86 % monomer conversion. The mixture was purified by precipitation in methanol to yield a polymer with Mn = 20,600 g.mol -1 with Ð = 1.38. The macroinitiator agent was subsequently placed in a 25 mL RBF equipped with rubber seals and a magnetic stirring bar in the presence of styrene (1.93 g, 1.84 x 10 -2 mol,

[M]0/[macro initiator agent]0 = 382) and toluene (3 g). The mixture was deoxygenated for 30 minutes purging nitrogen and subsequently placed in an oil bath at 97 °C.

Polymerization was carried out under stirring for 8 hours to reach 93 % conversion.

The polymer solution was quenched by cooling in contact with air, precipitated three times in methanol and dried under vacuum to yield the purified diblock copolymer ( Mn = 55,000 g.mol -1 , Ð = 1.50)

Synthesis of THGMA in NMP miniemulsion

The formulations used are given in Table 5.2. The organic phase consisted of a homogeneous mixture of THGMA (10.09 g, 4.41 x 10 -2 mol), Dispolreg 007 (varying amounts to target different DPns, see Table 5.2), and stearyl methacrylate (0.52 g, 5 wt% based-on-monomer, b-o-m) that was utilized as co-stabilizer. The aqueous phase consisted of a mixture of Dowfax 2A1 ( 45 wt% active content) (0.66 g, 3 wt% b-o-m) and deionised water. The organic phase was transferred to the aqueous phase and stirred for 30 min to yield a coarse pre-emulsion. Then, the pre-emulsion was sonicated using a Branson 450 sonifier operating at 80% output and 0.8 duty cycle for 10 min in an ice bath under magnetic stirring, thus yielding a stable miniemulsion.

The miniemulsion (droplet diameter in the range of 170 nm ) prepared as detailed above was transferred to a round bottom flask sealed with silicone rubber and the mixture was deoxygenated purging nitrogen for 30 min. Then, the miniemulsion was placed in an oil bath at 97°C and the polymerization was carried out under stirring for 8 hours, with samples carefully taken via a deoxygenated syringe. Monomer conversion was calculated by gravimetry.

Poly(THGMA)-b-poly(CDMMA) diblock copolymers in miniemulsion

The formulations used for the synthesis of poly(THGMA)-b-poly(CDMMA) diblock copolymers are summarized in Table 5.3. A poly(THGMA) seed latex 10 wt% solids ([M]0/[Dispolreg 007]0 = 225, Mn,th = 50,400 g.mol -1 ) was first prepared via NMP miniemulsion as described above. The reaction was stopped at 98 % monomer conversion, yielding a polymer with Mn = 50,000 g.mol -1 and Ð = 1. 13 The poly(THGA) seed latex (25 g) was charged to the reactor equipped with rubber seals and magnetic stirring bar before deoxygenation with purging nitrogen gas for 30 min.

Nitroxide mediated miniemulsion polymerization of using terpene methacrylate 169 Subsequently, the mixture of CDMMA monomer (3.5 g, [M]0/[macro initiator]0 = 312) and acetone (10 wt.% b-o-m) was added to the reactor and stirred for 60 min. Acetone was added to facilitate the mass transport of CDMMA to the seed particles. As discussed in Chapter 4, acetone presents the advantage of having benign toxicity and easily removable as shown in the industrial production of polyurethane dispersions. 32 The reactor was then placed in an oil bath at 97°C and allowed to polymerize for 8 hours. After polymerization, the reaction was cooled to room temperature.

Poly(THGMA)-b-poly(S) diblock copolymers in miniemulsion

The formulations used in these syntheses are given in Table 5.

Characterization

Monomer conversion was calculated from 1 H NMR (CDCl3, 400 MHz) and gravimetric for NMP in solution and miniemulsion, respectively, the information is given in Appendix Ι.

The theoretical molar masses were calculated using equation 4, the information is given in Appendix Ι. In all cases, high conversion was reached in 6 hours. At 90 ºC, an increase of the polymerization rate over time is evident in Figure 5.1A and the molecular weight was higher than the theoretical one. Both results suggest a slow opening of Dispolreg 007 at that temperature. This problem was solved at 97 ºC, when a linear kinetic plot, good match between the theoretical and the experimental molar masses, and a low value of the dispersity were obtained (at 95 ºC, there was still some deviations of the molar masses in the first part of the reaction). Therefore, 97 ℃ were retained for further reactions.

In order to clarify this point, a poly(THGMA) with DPn = 400 was synthesized in toluene and the polymerization was stopped at 82 % conversion to yield a polymer with Mn = 70,000 g.mol -1 and Ð = 1.50. The presence of macromonomer was checked with 1 H NMR. g.mol -1 ) to DPn 309 (Mn = 70,000 g.mol -1 , Ð = 1.50), which is close to the deviation observed in Figure 5.3B. It is worth pointing out that although this confirms the existence of side reactions, it is not possible to determine which of these reactions is the main responsible for the formation of macromonomers. The reason is that all of the side reactions give the same type of macromonomer. In this regard, it should be mentioned that Simula et al. 33 have shown that disproportionation between the nitroxide and the radical is the main cause of macromonomer formation at high conversions. Finally, it should be stressed that the amount of macromonomer formed with Dispolreg 007 is lower than those obtained with other NMP control agents. 33,35,38

Diblock copolymers

One of the most attractive aspects of the RDRP is the ability to synthesize block copolymers. In order to test the versatility of the Dispolreg 007 to form block copolymers, styrene was used to form a soft/hard diblock copolymer. To this end, a 1 with Ð 1.30). Subsequently, styrene was added to the mixture as a single shot and polymerized at 97 ℃ for 8 hours. The success of the chain extension is shown in Figure 5.5A, where it can be seen that the MMD of the copolymer shifted toward higher molar masses (98 % conversion, Mn = 55,000 g.mol -1 ) with a relatively low dispersity. Herein, the soft/hard diblock copolymer contained 41 wt.% of poly(THGMA), and 59 wt.% of poly(S).

Figure 5.5B presents the AFM image of the copolymer. It can be seen that the diblock copolymer clearly showed a two-phase lamellae morphology (the bright domains correspond to poly(styrene) and the dark ones to poly(THGMA)). In agreement with the theoretical predictions that when the fractions of both polymers are similar, a lamellae structure is formed. 40 The molecular weight was extracted from SEC-MALS analysis using the measured dn/dc value for poly(THGMA) (dn/dc = 0.056 mL.g -1 ) and poly(styrene) (dn/dc = 0.187 mL.g -1 ).

NMP miniemulsion of THGMA

The effect of targeted degree of polymerization

Once it was checked that the NMP of THGMA could be carried out under controlled conditions by using Dispolreg 007, the NMP of THGMA in miniemulsion was addressed. DPns ranging from 50 to 500 were tested to evaluate the degree of control of the system. As observed when the THGMA was polymerized in NMP 5.4. Pleasingly, at high targeted DPn (DPn 400 and 500), the molecular weights were still close to the predicted line, which differs from the results observed in the polymerization of THGMA in toluene. This could be attributed to the effect of the compartmentalization, which can decrease the rate of termination between propagating radicals due to the segregation of the propagating radicals in the different particles. 41 However, this would imply that bimolecular radical termination is the main side reaction and Simula et al. 33 have shown that this is not the case and that the main reason is the disproportionation between a propagating and nitroxide radicals. A more likely reason for the lower prominence of the nitroxide-propagating radical disproprotionation is the fast recombination of the propagation radical and the nitroxide resulting from the activation of the macroalkoxyamine in the confined environment of the polymer particle. This recombination will decrease the concentration of free and nitroxide radicals and therefore the disproportionation is less likely. It has been suggested that in the case of Nitroxide mediated miniemulsion polymerization of using terpene methacrylate 181 radical polymerization where various reactions are competing (e.g. propagation, transfer to polymer, disproportionation), the reaction of higher rate (e.g. reversible deactivation in RDRP) could suppress the reaction of slower rate (e.g. chain transfer to polymer). 42 . c Extracted from SEC-MALS analysis using the measured dn/dc value for poly(THGMA) (dn/dc = 0.056 mL.g -1 ) Chapter 5

Diblock copolymers

The successful polymerization of THGMA via NMP in aqueous media being achieved, the synthesis of waterborne adhesive based on full terpene soft/hard diblock Nitroxide mediated miniemulsion polymerization of using terpene methacrylate 5.5) a lamellae structure should be obtained for poly(THGMA) -b-poly(CDMMA) diblock coplymers. However, a relatively limited segregation between soft and hard phases is observed resulting in a mixed phase transition. This may be due to the presence of some dispersity in both molecular weights and chain composition, thus limiting the segregation of the soft and hard phases into one defined transition. 43,44 The rheology of the block copolymers was performed using parallel plate geometry with constant strain on a rotational rheometer (TA ARES). Mechanical spectroscopy experiment was performed at frequency 0.1 rad/s over the temperature from 160 to -60 ˚C.

In addition, the phase-separated of soft/hard diblock copolymer was further investigated with rheological measurements. poly(THGMA)50000-b-poly(S)29400) were obtained. In Figure 5.9, SEC evidences the success of the chain extension as in both cases the MWD is shifted to higher molar masses after chain extension with styrene (95 % conversion, Mn = 127,000 g.mo -1 and 97 % conversion, Mn = 79,400 g.mol -1 )). A monomodal distribution was obtained for the diblock copolymers with a slight increase in dispersity. The broadening of the molecular weight distribution that was also observed for the poly(THGMA)-bpoly(CDMMA) diblock copolymers (Figure 5.7) might be due to the small fraction of dead chains formed during the synthesis of the macro-initiator. ). This could be due to the effect of interaction parameter (Flory-Huggins interaction parameter, χ) between poly(THGMA) and poly(CDMMA) or poly(S), which affects the block copolymer segregation. 45,46 It can be seen that at high value interaction parameters (THGMA vs S) led to strong segregation. On the other hand, lower value interaction parameters (THGMA vs CDMMA) led to weaker segregation (Figure 5.7B and D). They show the expected result, for the two types of block copolymers, both G' and G'' increased with the content of hard polymer. However, although they may A point in the adhesive tests that is remarkable is the adhesive failure observed in the shear tests. Considering that the molecular weight of the block copolymers is relatively low (at least if they are compared with the common acrylic PSAs) and that the linear rheology shows a liquid behavior at low frequencies, one would expect a cohesive failure as it was observed in Chapter 4 for the tri-block copolymers. The adhesive failure suggests the presence of a weak interface. This weak interface could be formed by relatively shorter and softer chains that preferentially migrate to the interface.

In the discussion on the synthesis of the block copolymers, it was commented that the increase of dispersity observed during chain extension was due to terminations occurring during both the synthesis of the macro-initiator or during chain extension. In both cases, the dead polymer chains will have shorter lengths and will be softer than the average block copolymer. Migration of these chains to the film-substrate interface will lead to the formation of weak boundary. Migration is expected to be stronger for less compatible polymers. 48 In this regard, the compatibility between a THGMA-rich or even pure polymer chains and the block copolymers will be less when the fraction Nitroxide mediated miniemulsion polymerization of using terpene methacrylate 195 of hard monomer (CDMMA or St) increased, namely that more migration is expected for THGMA/CDMMA = 50,000/74,000 than for THGMA/CDMMA = 50,000/27,000 and for THGMA/St = 50,000/77,000 than for THGMA/St = 50,000/29,400.

This may justify the results of the adhesive tests because increase of the hard monomer content will result in a decrease of the work of adhesion and an increase in the peel resistance that agree with the rheological measurements. In parallel, the increase in the hard monomer content enhanced the migration of the short and soft polymer chains to form a weak boundary layer that lowered the shear resistance through an adhesive failure. This weak layer may take some time to form and therefore it was more evident in the low frequency shear test.

Adhesion

Comparison with the acrylates-based tri-block copolymers obtained in Chapter 4 shows that the methacrylate-based block copolymers presented better adhesive properties. However, as no attempt to optimize the PSAs was done and no formulated adhesives were used, no conclusions about the final performance of these PSAs can be made.

Conclusions

This chapter presents the synthesis of block copolymers from bio-sourced THGMA-St copolymers were also synthesized for comparison purposes. Well-defined phase-separation between soft and hard polymers was observed. The adhesive properties of the diblock copolymers were evaluated with probe tack, peel strength and shear resistance measurements. It was found that migration of the short polymer chains could affect the shear resistance. The adhesive performance was comparable to the partially petroleum-based styrene system and better than that found for the acrylatebased triblock copolymers.

Resumen y Conclusiones

Esta tesis de doctorado tiene como objetivo contribuir a la reducción de la dependencia del petróleo mediante la producción de polímeros utilizando monómeros obtenidos de terpenos de origen biológico. Los terpenos son subproductos de la industria papelera local creada alrededor del bosque de pinos "Las Landas". El tetrahidrogeraniol (THG) y el ciclademol (CDM) se eligieron como derivados de terpeno para preparar monómeros (met)acrílicos que pueden reemplazar a sus homólogos a base de petróleo (acrilato de n-butilo, acrilato de 2-etilhexilo, metacrilato de metilo y estireno). Se desarrolló un método sintético para la producción eficiente de varios (met)acrilatos que contienen terpeno (acrilato de tetrahidrogeraniol (THGA), metacrilato de tetrahidroheranoiol (THGMA), acrilato de ciclademol (CDMA) y metacrilato de ciclademol (CDMMA). Estos monómeros se polimerizaron en masa, en solución y en sistemas dispersos acuosos mediante polimerización por radicales libres, polimerización RAFT y polimerización mediada por nitróxido (NMP). tribloques consisten solo en derivados de terpenos, maximizando así el uso de recursos renovables. Una característica importante del proceso desarrollado es su escalabilidad, ya que no se necesita una etapa de purificación intermedia después de la síntesis del primer bloque. La segregación de nanofase de los copolímeros se observó mediante AFM y mediciones reológicas. Finalmente, las formulaciones que utilizan monómeros totalmente biológicos mostraron un buen comportamiento adhesivo, en comparación con los copolímeros tribloque parcialmente basados en estireno.

Los copolímeros de bloque de metacrilatos basados en terpeno de origen biológico se sintetizaron con éxito mediante polimerización mediada por nitróxido (NMP) usando la alcoxiamina Dispolreg 007. La NMP de THGMA se realizó primero en tolueno con un buen control sobre la polimerización para grados de polimerización de hasta DPn = 200. En DPn objetivos más altos, se observó evidencia del macromonómero que conduce a una masa molar reducida en comparación con el valor Resumen y conclusiones 217 predicho. Cuando el proceso se llevó a cabo en miniemulsión, se pudo lograr un control excelente sobre la polimerización de THGMA hasta DPn 500 y se obtuvieron distribuciones de peso molecular estrechas a alta conversión. La mejora se atribuyó a la rápida recombinación del radical y el nitróxido en el ambiente confinado de las partículas de polímero. Los copolímeros dibloque blando/duro a base de terpeno se sintetizaron con éxito comenzando con un macroradical THGMA, variando el peso molecular del polímero duro (CDMMA). Los copolímeros dibloque THGMA-S también se sintetizaron con fines comparativos. Se observó una separación de fases bien definida entre polímeros blandos y duros. Las propiedades adhesivas de los copolímeros dibloque se evaluaron con medidas de pegajosidad de sonda, resistencia al desprendimiento y resistencia a la cizalla. Se descubrió que la migración de las cadenas cortas de polímero afectaba la resistencia al corte. El comportamiento adhesivo fue comparable al sistema de estireno parcialmente a base de petróleo y mejor que el encontrado para los copolímeros tribloque a base de acrilato.

Conclusions

Cette thèse a pour objectif de contribuer à la réduction de la dépendance au pétrole en produisant des polymères à partir de monomères obtenus à base de terpènes

Figure 1 . 1 .

 11 Figure 1.1. Global production capacities of bioplastics.

Figure 1 . 2 .

 12 Figure 1.2. Chemical structure of some common terpenes.

Scheme 1 . 5 .

 15 Scheme 1.5. The mechanism of NMP polymerization.

95 , 96 1. 3 . 2 Scheme 1 . 6 . 1 28Figure 1 . 3 .Figure 1 . 3 .

 9596321611313 Scheme 1.6. The mechanism of RAFT polymerization.

Figure 1 . 5 . 1 34

 151 Figure 1.5. Scheme of microphase separated morphologies in block copolymer system. 140

Chapter 1 38 In Chapter 3 ,In Chapter 4 ,In Chapter 5 ,

 38345 the synthesized bio-sourced based monomer THGA is polymerized by free radical and reversible-addition fragmentation chain transfer (RAFT) polymerization in bulk and solution. The effects of monomer concentration and the degree of polymerization (DPn) are investigated. Finally, the retention of reactive chain ends is exploited to yield a soft/hard/soft and hard/soft/hard triblock copolymers poly(THGA-b-styrene-b-THGA). Thermal analysis and AFM imaging are used to further analyse this ABA triblock copolymer. the THGA monomer based on linear terpene derivative is polymerized by RAFT miniemulsion polymerization. Different types of initiators and the degree of polymerization are studied. The poly(THGA) and poly(CDMA) are used to prepare the poly(THGA)-b-poly(CDMA)-b-poly(THGA) soft/hard/soft and poly(CDMA)-bpoly(THGA)-b-poly(CDMA) hard/soft/hard triblock copolymers. Furthermore, the adhesive properties of full terpene triblock copolymers between THGA and CDMA are compared with those of a triblock copolymer based on styrene. nitroxide-mediated polymerization (NMP) is utilized to polymerize the THGMA monomer in solution and miniemulsion in the presence of 3-(((2cyanopropan-2-yl)oxy)(cyclohexyl)amino)-2,2-dimethyl-3-phenylpropanenitrile (Dispolreg 007). The effects of temperature of polymerization and the degree of polymerization are studied for the NMP in solution. In NMP miniemulsion polymerization, the stability and the degree of polymerization of poly(THGMA) are investigated. Furthermore, the poly(THGMA) is extended with a hard monomer (CDMMA) to form the soft/hard diblock copolymer, and the adhesive performance is compared with the block copolymers based on styrene.

, in which rosin based monomers bearing an acrylate moiety were prepared by Chapter 2 68 esterification

 68 of pendant hydroxyl and acid groups. This yielded a higher incorporation of the terpene based materials into polymer matrices. More recently, Howdle et al.14 utilized commercially available cyclic terpenes (e.g. α-pinene, β-pinene, limonene and carvone) to prepare (meth)acrylate based monomers via oxidation and subsequent esterification of the hydroxyl groups. The free radical polymerization of those monomers resulted in high monomer conversions (> 95 %), thus yielding polymers of a few thousands Daltons (up to 𝑀 ̅ n ~ 23,600 g.mol -1 ). The bio-based (meth)acrylic polymers displayed interesting thermal properties, with Tg ranging from 12 to 142 °C.In this work, we focus our attention to synthesize a new class of renewable biobased monomers from side products of the local paper industry of the "Landes" forest in the South West of France. This is the biggest European farmed forest and produces thousands of tons of functional organic renewable molecules extracted from the black liquor, i.e. terpenes, especially. Tetrahydrogeraniol (THG) and cyclademol (CDM) (Figure2.1) were selected. THG has a branched-linear structure that is expected to give a low Tg polymer as its synthetic homologue, i.e. EthylHexyl. On the other hand, the cyclic structure of CDM is expected to yield a hard polymer mimicking the chemical structure of the Norbornyl group. Combination of these monomers opens a wide range Monomer Synthesis 69 of possibilities, although this PhD thesis focuses on the block copolymers for bio-based adhesives.

Figure 2 . 1 .

 21 Figure 2.1. Structure of tetrahydrogeraniol (THG) and cyclademol (CDM).

  38 (b) (dd, 1H, CH2=CH-C=O), 6.12 (c) (s, 1H, CH2=CH-C=O), 5.80 (a) (dd, 1H, CH2=CH-C=O), 4.18 (d) (s, O-CH2-CH2-CH2), 1.69 (k) (m, 1H, (CH3)2-CH-CH2), 1.50 (e) (m, 2H, CH-CH2-CH2-O), 1.47 (f) Monomer Synthesis 75 (m, 1H, CH3-CH-CH2-CH2), 1.28 (i) (m, 2H, CH-CH2-CH2-CH2-CH), 1.14 (h, j) (m, 4H, CH-CH2-CH2-CH2-CH), 0.91 (g) (d, 3H, CH3-CH-CH2-CH2), 0.89 (l) (d, 6H, (CH3)2-CH-CH2-CH2). The signal of 13 C NMR of monomer, as follow: Cc (166), Ca (130), Cb (129), Cd (63), Cj(39), Ch (37), Ce(35), Cf(30), Ck(28), Ci(25), Cl(23), Cg(19).

Figure 2 . 2 .

 22 Figure 2.2. 1 H and 13 C NMR of THGA monomer by acryloyl chloride.

  reduces the environmental impact.14 THGA, THGMA, CDMA and CDMMA were synthesized by using (meth)acrylic acid. The success of the reaction was confirmed by 1 H NMR (Figure 2.3), showing the presence of the reactive vinyl bonds. The 1 H NMR signals of these monomers show as follow, THGA monomer; 6.37 (b) (dd, 1H, CH2=CH-C=O), 6.11 (c) (s, 1H, CH2=CH-C=O), 5.80 (a) (dd, 1H, CH2=CH-C=O) 4.18

Chapter 2 78 Figure 2 . 3 . 1 H

 78231 Figure 2.3. 1 H NMR of the synthesized terpene monomers by (meth)acrylic acid.

sourced elastomeric building block in the design of functional acrylic copolymers 3 . 1 . 86 THGA

 3186 terpenes (~ 82 %) and relatively moderate yields for acrylate functionality (~ 60 %) were obtained. The biosourced-based monomers synthesized in this chapter were utilized throughout this thesis. Introduction The studies reported in literature aimed at obtaining polymers based on terpenes are discussed in Chapter 1 and the reader is referred to that chapter. This chapter explores the possibility of synthesizing thermoplastic elastomers partially based on terpenes. The "soft" segment was formed by tetrahydrogeraniol acrylate (THGA) synthesized in Chapter 2. This monomer has a branched acyclic ten carbon structure that mimics petroleum-based soft monomer such as n-butyl acrylate and 2-ethylhexyl acrylate. The long branched structure promotes low glass transition temperatures (Tg ~ -46 °C).Chapter 3 was first polymerized by free radical polymerization in bulk and solution at 80 °C, yielding molar masses up to 𝑀 ̅ n = 278,000 g.mol -1 and monomer conversions up to 99 %. THGA was also polymerized in the presence of a bi-functional RAFT agent S,S´-dibenzyl trithiocarbonate (DBTTC). Degrees of polymerization ranging from DPn 25 to 500 were targeted. Finally, the retention of reactive chain ends was exploited to yield a soft/hard/soft triblock copolymer poly(THGA)-b-poly(styrene)-b-poly(THGA).

[ 88 [ 89 Table 3 . 1 .

 888931 DBTTC]0/[I]0 = 2 and maintaining constant the degree of polymerization targeted (DPn = 250) (Table3.1 entries 5-8). In addition, for a degree of polymerization of 250,[DBTTC]0/[I]0 = 10 was used (entries 9 to 12). The [M]0/[DBTTC]0 ratios were varied to target DPns of 25, 50, 100, 250 and 500 (Table3.1, entries 11 and 13 to 16). Chapter 3 DBTTC]0/[I]0 = 10 was used in these experiments except for entry 15 aiming at DPn = 25, where [DBTTC]0/[I]0 = 20 was used to limit termination.Typically, THGA (2.50 g, 1.18 x 10 -2 mol), the required amount of DBTTC and toluene (16 g) were placed into a 25 mL round bottom flask equipped with rubber seals and a magnetic stirring bar. The mixture was deoxygenated for 30 minutes with purging nitrogen and subsequently placed in an oil bath at 80 °C. Then a solution of AIBN (0.75 mg, 4.56 x 10 -6 mol) dissolved in a small amount of toluene was added as a shot to initiate the polymerization. The system was allowed to polymerize under stirring for 6 hours at 80 °C and samples were carefully taken via a deoxygenated syringe. The polymer solution was quenched by cooling and contact to air, precipitated three times in methanol and dried under vacuum to yield the purified polymer as a white powder.Renewable terpene derivative as a bio-sourced elastomeric building block in the design of functional acrylic copolymers Reaction conditions for the polymerizations of THGA

3 . 91 3. 2 . 2 . 4 .

 391224 Chain extension of poly(THGA) to yield a soft/hard/soft triblock copolymer A poly(THGA) based macro-RAFT agent was previously prepared in solution [M]0 = 3.6 mol.L-1, [DBTTC]0/[AIBN]0 = 10, [M]0/[DBTTC]0 = 98 and the polymerization stopped at 95 % conversion. The mixture was purified by precipitation in methanol to yield a polymer with Mn = 19,000 g.mol -1 , Ð = 1.07. The macro RAFTagent was subsequently placed in a 25 mL RBF equipped with a rubber seal and a magnetic stirring bar in the presence of styrene (10 g, 1.9 x 10 -2 mol, [St]0/[macro-CTA]0 = 500). The mixture was deoxygenated for 30 minutes with purging nitrogen and subsequently placed into an oil bath at 80 °C. Then, a solution of AIBN (2.8 mg, 1.7 x 10 -5 mol) dissolved in a small amount of toluene was added as a shot via a deoxygenated syringe to initiate the polymerization. Polymerization was left to stir for 8 hours at 80 °C to reach 89 % conversion. The polymer solution was quenched by cooling and contact to air, precipitated three times in methanol and dried under vacuum to yield the purified triblock copolymer (Mn = 68 000 g.mol -1 , Ð = 1.15). Renewable terpene derivative as a bio-sourced elastomeric building block in the design of functional acrylic copolymers Chain extension of poly(styrene) to yield an hard/soft/hard triblock copolymer A poly(styrene) based macro-RAFT agent was prepared in solution [M]0 = 3.6 mol.L-1, [DBTTC]0/[AIBN]0 = 10, [M]0/[DBTTC]0 = 97 and stopped at 92 % conversion. The mixture was purified by precipitation in methanol to yield a polymer with Mn = 8,600 g.mol -1 , Ð = 1.15. The macro RAFT-agent was subsequently placed in a 25 mL RBF equipped with a rubber seal and a magnetic stirring bar in the presence of THGA (5 g, 2.3 x 10 -2 mol, [THGA]0/[macro-CTA]0 = 503). The mixture was deoxygenated for 30 minutes with purging nitrogen and subsequently placed into an oil bath at 80 °C. Then, a solution of AIBN (0.76 mg, 4.6 x 10 -6 mol) dissolved in a small amount of toluene was added as a shot via a deoxygenated syringe to initiate the polymerization. Polymerization was left to stir for 8 hours at 80 °C to reach 90 % conversion. The polymer solution was quenched by cooling and contact to air, precipitated three times in methanol and dried under vacuum to yield the purified triblock copolymer (Mn = 98,500 g.mol -1 , Ð = 1.3) Chapter 3 92

3. 3 . 1 . 93 Scheme 3 . 1 .

 319331 Scheme 3.1. Reaction scheme to yield poly(THGA) and ABA triblock copolymer poly(THGA)-b-poly(styrene)-b-poly(THGA) from tetrahydrogeraniol.

  2 and Figure3.1 show that high monomer conversions could be reached. As the monomer to initiator ratio was fixed, increasing the initial monomer concentration resulted in an increase in conversion with near complete monomer conversion achieved in 3 hours for the reaction in bulk. The molecular weight was observed to increase for increasing concentration of the monomer in the reaction medium. The increase in molecular weight with increased monomer concentration is likely an effect of the increased tendency for intermolecular chain transfer reactions at reduced monomer concentrations. It should be noted that unlike what is observed in the polymerization of most acrylic monomers no gel formation was observed for the reaction in bulk.1

Figure 3 . 1 . 95 Figure 3 . 2 .

 319532 Figure 3.1. Evolution of the monomer conversion as a function of time during the free radical polymerization of terpene acrylate at 80 °C in toluene [M]0/[I2]0 = 516. (Squares) [M]0 = 0.6 mol.L -1 . (Circles) [M]0 = 1.8 mol.L -1 . (Up triangles) [M]0 = 3.6 mol.L -1 . (Down triangles) Bulk.

Figure 3 . 1 .

 31 Figure 3.2 presents the DSC thermograms of the homopolymers. All samples

Figure 3 . 3

 33 Figure 3.3 Kinetics of the RAFT polymerization of terpene acrylate at 80 °C in toluene at various monomer concentrations (Squares) [M]0 = 0.6 mol.L -1 ; (Circles) [M]0 = 1.8 mol.L -1 ; (Up triangles) [M]0 = 3.6 mol.L -1 ; (Down triangles) bulk (entries 5-8 in Table 3.3). The DPn = [M]0/[CTA]0 ratio is kept at DPn = 250. (A) Evolution of the ln([M]0/[M]) as a function of time. (B) Evolution of the measured molar masses as a function of monomer conversions; the dash line is a guide for the eye. (C) Evolution of the dispersity values as a function of monomer conversion. (D) Molar mass distributions of poly(terpene acrylate) prepared by RAFT polymerization at 80 °C ([M]0 = 3.6 mol.L -1 , DPn = 250) at various monomer conversions.1.8 M

[

  DBTTC]0/[I2]0 = 2, the monomodal molar mass distribution (MMD) could be obtained with relatively high dispersity values at low monomer concentration. In addition, for high conversions the experimental molar masses were lower than the theoretical ones showing that the number of polymer chains was not determined by the RAFT agent. (Figure 3.3). This was attributed to the low [DBTTC]0/[I2]0 ratio used in these experiments. Better control was achieved when the ratio was increased ([DBTTC]0/[I2]0 = 10). At all monomer concentrations, relatively low dispersity values (Ð ~ 1.2) were obtained(see Table

3 andFigure 3 . 3 100Figure 3 . 4 .

 33334 Figure 3.4B). This discrepancy cannot be attributed to errors in the calculation of the

Figure 3 . 5 .

 35 Figure 3.5. Quantitative 13 C NMR (CDCl3, 125 MHz) of a poly(THGA) prepared by RAFT polymerization at 80 °C in toluene (entry 6 in Table 3.3). [M]0 = 1.8 mol.L -1 , [M]0/[DBTTC]0 = 250 and [DBTTC]0/[I2]0 = 10. Spectra recorded at 91 % monomer conversion.

3 104Figure 3 . 6 . 1 H

 3361 Figure 3.6. 1 H NMR (CDCl3, 400 MHz) of poly(THGA) prepared by RAFT polymerization at 80 °C in toluene (entry 6 in Table2), [M]0 = 1.8 mol.L -1 at 91 % monomer conversion.

Figure 3 . 8 .

 38 Figure 3.8. Kinetics of the RAFT polymerization of terpene acrylate at 80 °C in toluene at various DPn = [M]0/[DBTTC]0 and [M]0 = 3.6 mol.L -1 . (Left triangles) DP 500; (Circles) DP 250; (Up triangles) DP 100; (Down triangles) DP 50; (Diamonds) DP 25. (A) Evolution of the ln([M]0/[M]) as a function of time. (B) Evolution of the measured molar masses as a function of monomer conversions; the dash lines are the theoretical evolution of molar masses calculated from equations 1 and 2. (C) Evolution of the dispersity values as a function of monomer conversion and (D) Molar mass distributions (from SEC-MALS) of the final sample of poly(terpene acrylate) prepared by RAFT polymerization at 80 °C ([M]0 = 3.6 mol.L -1 ) at various DPns (Entries 11 and 13 to 16 in Table3.3).

  initial [M]0 = 3.6 mol.L -1 , a ratio [DBTTC]0/[I2]0 = 10 and targeting a DPn = [M]0/[DBTTC]0 of 98. Subsequently, a second monomer aliquot (styrene herein,

Figure 3 . 9 .

 39 Figure 3.9. SEC traces of the chain extension of a poly(terpene acrylate) macro-RAFT agent with styrene at 80 °C.

Figure 3 . 10 .

 310 Figure 3.10. SEC traces of the chain extension of a poly(terpene acrylate)-copoly(fluorescein o-acrylate) macro-RAFT agent with styrene at 80 °C. (Left) Fluorescence detection, λ = 350 nm. (Right) DRI detection.

Figure 3 . 11 . 3 112

 3113 Figure 3.11. (A) AFM picture of a poly(THGA)-b-poly(styrene-b-poly(THGA) ABA triblock copolymer (LogDMT modulus with scale bar = 200 nm). (B) G´ (filled squares), G´´ (squares) and tan δ (filled triangles) as a function of the temperature of a PTHGA-b-PS-b-PTHGA ABA triblock copolymer.

Figure 3 .

 3 Figure 3.12. (A) SEC traces of the chain extension of a poly(styrene) macro-RAFT agent with THGA. (B) AFM picture of a poly(styrene)-b-poly(THGA)-b-poly(styrene) ABA triblock copolymer (LogDMT modulus with scale bar = 200 nm). (C) G´ (filled squares), G´´ (squares) and tan δ (filled triangles) as a function of the temperature of a PS-b-PTHGA-b-PS ABA triblock copolymer.

(

  DBTTC, calculated by targeting a certain DPn = [M]0/[DBTTC]0) and co-stabilizer (stearyl acrylate at a concentration of 5 wt.% based-on-monomer, b-o-m)). The aqueous phase consisted of a surfactant (Dowfax 2A1 at a concentration of 3 wt.% b-o-m) solution in deionized water (amount calculated to reach 10-25 wt.% solids content). It was found that 3 wt.% b-o-m of surfactant and 5 wt.% b-o-m of co-stabilizer were necessary to prevent droplets coalescence and Ostwald ripening, as evidenced by light backscattering (Figure 4.1)

Figure 4 . 1 .

 41 Figure 4.1. Stability of the THGA dispersion at 60 ˚C. The scans were conducted every 30 min for 5 h with 20 wt% solids content. (A) entry 1; 2 wt.% surfactant and 4 wt.% co-stabilizer. (B) entry 2; 3 wt.% surfactant and 5 wt.% co-stabilizer based on terpene acrylate.

  the redox initiating couple was utilized, the reductant (AsAc) was added as a single shot to the reaction after miniemulsification and the TBHP was subsequently fed into the reaction mixture for 30 minutes. The various reaction conditions are summarized in Table4.1.

129 4 . 2 . 2 . 2 .

 4222 Synthesis of poly(THGA)-b-poly(CDMMA)-bpoly(THGA) soft/hard/soft triblock copolymers A poly(THGA) seed latex with 10 wt% solids ([M]0/[DBTTC]0 = 262, [DBTTC]0/[I2]0 = 10) was first prepared via RAFT miniemulsion polymerization as described above. The reaction was stopped at 95 % monomer conversion, yielding a polymer with Mn = 51,000 g.mol -1 and Ð = 1.2. The poly(THGA) seed latex (40 g) was charged into a 250 mL RBF equipped with rubber seals and magnetic stirring bar before deoxygenation by purging nitrogen for 30 min. Subsequently, a mixture of CDMA monomer (3.99 g, 18.9 mmol, [M]0/[macro RAFT agent]0 = 241), AIBN ([DBTTC]0/[I2]0 = 11) and acetone (10 wt.% b-o-m) was added to the reaction as a single shot and stirred for 30 min. Acetone was added to facilitate the incorporation of CDMA and AIBN to the poly(THGA) particles. Acetone presents the advantage of

Chapter 4 130 4 . 2 . 2 . 3 . 4 . 2 . 2 . 4 .

 442234224 Synthesis of poly(CDMMA)-b-poly(THGA)-bpoly(CDMMA) hard/soft/hard triblock copolymers Poly(CDMMA) seed latex (10 wt% solids content) was prepared via RAFT miniemulsion polymerization. The organic phase consisted of a homogeneous mixture of CDMMA (10 g, 4.75 × 10 -2 mol), initiator (16 mg, 9.74 x 10 -5 mol, [CTA]/[I2] = 10), DBTTC (0.29 g, 9.74 x 10 -5 mol, [M]/[CTA] = 48) and stearyl acrylate (0.5 g, 5wt.% based-on-monomer, utilized as as a co-stabilizer) . The aqueous phase consisted of a mixture of Dowfax 2A1 (0.66 g, 3 wt.% b-o-m) dispersed in deionised water. The preparation of the miniemulsion was similar as describe above. The miniemulsion (particle size 186 nm ) was transferred into a round bottle flask sealed with silicone rubber and the mixture was deoxygenated by purging nitrogen for 30 min. Then, the miniemulsion was placed in an oil bath at 70°C and the polymerization was carried out for 7 h under stirring. The reaction was stopped at 97 % conversion with the 𝑀 ̅ n = 13,000 g.mol -1 with Ð = 1.10. Then, the poly(CDMA)(10 wt% solid content) seed latex (20 g, 1.96 × 10 -4 mol) was charged into the reactor equipped with the rubber seal and magnetic stirring bar, and deoxygenated with nitrogen for 30 min. Subsequently, the mixture of THGA (5.10 g, [M]0/[macro RAFT agent]0 = 156), AIBN (3.2 mg, [DBTTC]0/[I2] = 8 ) and acetone (10 wt.% b-o-m) was added to the reactor and stirred Paving the way to sustainable waterborne pressure-sensitive adhesives using terpenebased triblock-copolymer 131 for 30 min. The reactor was then placed in an oil bath at 70°C and the polymerization was carried out for 8 h. After the polymerization, the reaction was cooled to room temperature. Synthesis of poly(THGA)-b-poly(S)-b-poly(THGA) soft/hard/soft triblock copolymers A poly(THGA) seed latex 10 wt% solids ([M]0/[DBTTC]0 = 251, [DBTTC]0/[I2]0 = 10,) was first prepared via RAFT miniemulsion polymerization as described above. The reaction was stopped at 97 % monomer conversion, yielding a polymer with Mn = 50 000 g.mol -1 and Ð = 1.28. The poly(THGA) seed latex (40 g) was charged to the reactor and purged with nitrogen for 30 min. Subsequently, the mixture of styrene (4.16 g, [M]0/[macro RAFT agent]0 = 500), AIBN (1.3 mg, [CTA]0/[I2]0 = 9) and acetone (10 wt.% b-o-m) was added to the reactor and stirred for 30 min. The reactor was then placed in an oil bath at 70°C and allow to polymerize for 8 h. After polymerization, the reaction was cooled to room temperature. Chapter 4 132

4. 3 . 1 . Miniemulsion homopolymerization of THGA 4 . 3 . 1 . 1 .

 314311 The effect of type of initiatorWe first investigated the RAFT homopolymerization of THGA in miniemulsion (Scheme 4.1) (DPn = [M]0/[DBTTC]0 = 50, at 70 ºC). Once a stable miniemulsion was reached (see experimental section), we looked at the most efficient way to initiate polymerization. Hence, three types of initiators were tested, which directly impact the concentration of initiating radical in the monomer droplets. Upon decomposition, the hydrophobic initiator azobisisobutyronitrile (AIBN) initiates polymerization inside the Paving the way to sustainable waterborne pressure-sensitive adhesives using terpenebased triblock-copolymer 133 droplets, whilst the hydrophilic potassium persulfate (KPS) generates radicals in the aqueous phase. A redox couple tert-butyl hydroperoxide/ascorbic acid (TBHP/AscA)

Chapter 4 134Figure 4 .

 44 Figure 4.2B highlights the evolution of the particle size during the

Figure 4 . 2 .

 42 Figure 4.2. Kinetic of the RAFT miniemulsion polymerization of poly(THGA) with different initiators at 70°C, DPn = 50, [CTA]0/[I2]0 = 10. (Squares) KPS; (Circles) AIBN and (Up triangles) TBHP/Asc. (A) Conversion plot as a function of time. (B) Evolution of the particle size as a function of time. (C) Evolution of the measured molar masses as a function of monomer conversion. (D) Evolution of dispersity values as a function of monomer conversion.

2 and Figure 4 .

 24 conversion) were reached after 6 hours, as detailed in Table4.3A. A lower rate of polymerization can be observed in Figure4.3A when a DPn of 50 was targeted. In comparison, the rate of polymerization for higher targeted

Figure 4 . 3 .

 43 Figure 4.3. The kinetic plot of the poly(THGA) by RAFT miniemulsion polymerization at 70°C for 7 h with AIBN as an initiator at different targeted DPns; DP 50 (Squares), DP 250 (Cycles), DP 350 (Up triangles), and DP 450 (Down triangles). (A) Conversion plot as a function of time. (B) Evolution of the particle size as a function of conversion. (C) Evolution of the molar mass as a function of conversion. (D) Dispersity values as a function of conversion.

1 . 2 , 4 142In Figure 4 .

 1244 to sustainable waterborne pressure-sensitive adhesives using terpenebased triblock-copolymer 141 The first PTHGA block was synthesized by RAFT miniemulsion polymerization at 70 ºC (DPn = 262; [DBTTC]0/[I2]0 = 10) reaching 95 % conversion in 8 hours. This yielded a macro-RAFT agent with Mn = 51,000 g.mol -1 ) and low dispersity value (Ð = Figure 4.4A). Subsequently, the "livingness" of this "soft" block was tested via the addition of CDMA and initiator ([CDMA]/[macro-RAFT] = 241 and [Macro-RAFT]0/[I2]0 = 10). A small amount of acetone was also added (10 wt.% b-o-m) with the monomer to promote the diffusion of the monomer through the aqueous phase into the polymer particle. Acetone was selected for its good miscibility, benign toxicity and facile removal by the end of the polymerization (bp = 56 ºC). It should be stressed that in the absence of solvent, the chain extension was not successful, with low monomer conversions attained (< 60 %, data not shown) and no apparent change in molar mass. A PTHGA-b-PCDMA-b-PTHGA triblock was obtained with 96 % monomer conversion of the second block after 8 hours of polymerization. This is confirmed by SEC in Figure 4.4A, with the molar mass distributions shifting towards higher masses upon chain extension. The PTHGA-b-PCDMA-b-PTHGA triblock reached a molar mass of Mn = 105,500 g.mol -1 and the dispersity value remained relatively low (Đ ~ 1.6). The slight increase in dispersity value upon chain extension may be due to the presence of residual dead chains. Chapter 4B, a phase separation can be observed in AFM for the PTHGA-b-PCDMA-b-PTHGA triblock copolymer, with the bright domains corresponding to the "hard" phase (54 wt.% of PCDMA) and the dark domains corresponding to the "soft" phase (46 wt.% of PTHGA). The triblock configuration is further evidenced through rheological measurement, with the appearance of two major glass transition temperatures (Tg) in Figure 4.4C. Details of the values of Tgs and G', G'' cross over can be found in Table 4.4.

a

  extracted from 1 H NMR. b extracted from the local maxima of tan(δ).

Figure 4 . 4 . 4 144Figure 4 . 5 .

 44445 Figure 4.4. (A) and (D) SEC-MALS; (B) and (E) AFM (PeakForce QNM mode); (C) and (F) Rheological behavior for PTHGA-b-PCDMA-b-PTHGA and PCDMA-b-PTHGA-b-PCDMA.

Figure 4 . 6 .Table 4 . 5 .

 4645 Figure 4.6. Films casted at 23 ºC and 55 % humidity. (A) PTHGA-b-PCDMA-b-PTHGA. (B) PCDMA-b-PTHGA-b-PCDMA.

Dispolreg 007 .

 007 Reactions 1-3 were carried out and different temperatures (90, 95 and 97 ºC) aiming at the same degree of polymerization, DPn = 25. Reactions 3-6 were carried out at 97 ºC aiming at different degrees of polymerization. The formulations are given in Table 5.1. Typically, THGMA (2 g, 8.83 x 10 -3 mol) and toluene (2 g) were placed into a 25 mL RBF equipped with rubber seals and a magnetic stirring bar. Dispolreg 007 was added in order to adjust the [M]0/[Dispolreg 007]0 ratio to the target DPn (25, 100, 200 and 400). The mixture was deoxygenated for 30 minutes by purging nitrogen and subsequently placed into an oil bath at 97 °C. Polymerization occurred under stirring for 6 hours and samples were carefully withdrawn via a deoxygenated Nitroxide mediated miniemulsion polymerization of using terpene methacrylate 165 syringe. Monomer conversion was calculated from 1 H NMR by comparison of the vinyl signals and OCH2 signals The polymer solution was quenched by cooling in contact with air, precipitated three times in methanol and dried under vacuum to yield the purified polymer as a white powder.

  3. A poly(THGMA) seed latex 10 wt% solids ([M]0/[Dispolreg 007]0 = 225, Mn,th = 50,400 g.mol -1 ) was first prepared via NMP miniemulsion as described above. The reaction was stopped at 98 % monomer conversion, yielding a polymer with Mn = 50,000 g.mol - 1 and Ð = 1.13. The poly(THGA) seed latex (25 g) was charged to the reactor equipped with rubber seals and magnetic stirring bar before deoxygenation with purging nitrogen gas for 30 min. Subsequently, the mixture of styrene monomer (3.5 g, [M]0/[macro initiator agent]0 = 672) and acetone (10 wt.% b-o-m) was added to the reactor and stirred for 60 min. The reactor was then placed in an oil bath at 97°C and left to Chapter 5 170 polymerize for 8 hours. After polymerization, the reaction was cooled to room temperature.

5. 3 . Results and discussion 5 . 3 . 1 . NMP solution of THGMA 5 . 3 . 1 . 1 .

 35315311 The effect of the temperature reactionThe synthesis of tetrahydrogeraniol methacrylate (THGMA) monomer was carried out by incorporation of a methacrylic group. The successful synthesis of the monomer was presented in Chapter 2. The bio-sourced THGMA was polymerized in toluene in the presence of the alkoxyamine Dispolreg 007 (Scheme 5.1). Previous experience in the polymerization of methacrylates using Dispolreg 007 shows that the adequate range of polymerization temperatures is about 90 ºC.26, 27, 33 Therefore, polymerizations were carried out at 90, 95 and 97 ℃ , targeting a degree of polymerization (DPn) of 25.

Figure 5 . 1 .

 51 Figure 5.1. Polymerization of THGMA ([M]0/[Dispolreg 007]0 = 25) in toluene, [M]0 = 1.95 mol.L -1 t at 90 (Squares), 95 (Circles) and 97 ºC (Up triangles). (A) Evolution of Ln[M]0/[M] as a function of time. (B) Evolution of the measured molar masses as a function of monomer conversion. (C) Evolution of the dispersity values as a function of monomer conversion.

Figure 5 .

 5 4 shows that the 1 H NMR spectrum revealed the vinyl resonances (δ = 6.2 and 5.5 ppm) indicative of unsaturated carbon. It could be confirmed that the disproportionation termination occurred during the course of polymerization. The percentage of macromonomer calculated from the ratio between the areas of the peaks from the macromonomer and OCH2 was 0.09 % at 82 % conversion. This small percentage can cause a decrease of DPn from 332 (Mn =75,200

Figure 5 . 3 .

 53 Figure 5.3. Kinetics of the polymerization of THGMA at 97 °C in toluene via NMP at various targeting degree of polymerization (Squares) DPn 25; (Circles) DPn 100; (Up triangles) DPn 200; (Down triangles) DPn 400. (A) Evolution of Ln([M]0/[M]) as a function of time. (B) Evolution of the measured molar masses as a function of monomer conversion; the dash lines are a guide for the eye. (C) Evolution of the dispersity values as a function of monomer conversion. (D) Molar mass distributions (from SEC-MALS) of the final sample of poly(THGMA).

Figure 5 . 4 . 1 H

 541 Figure 5.4. 1 H NMR (CDCl3, 400 MHz) of poly(THGMA) ([M]0/[Dispolreg 007]0 = 400, Mn = 70,000 g.mol -1 , Ð = 1.50 at 82 % conversion) prepared by NMP in toluene at 97 ℃.

  ) was prepared in toluene via NMP (90 % conversion, Mn = 20,600 g.mol -

Figure 5 . 5 .

 55 Figure 5.5. (A) SEC traces of the chain extension of a poly(THGMA) macro-initiator agent with styrene in toluene at 97 ℃ for 8 hours. (B) AFM picture of poly(THGMA)b-poly(S) soft/hard diblock copolymer (log DMT modulus with scale bar = 200 nm).

  rate increased when lower DPn was targeted due to higher radical concentration (Figure5.6A). Figure5.6B shows that the particle size was constant all along the polymerization, indicating the efficient droplet nucleation and the good colloidal stability of the system. The evolution of molecular weights increased linearly with the conversion and approached to the theoretical lines with relatively low dispersity values (Ð~1.25) as shown in Figure5.6C and Table

Figure 5 . 6 .

 56 Figure 5.6. Kinetics of the polymerization of THGMA at 97 °C in NMP miniemulsion at various targeted degree of polymerization (Squares) DPn 50; (Circles) DPn 100; (Up triangles) DPn 200; (Down triangles) DPn 400 and (Diamond) DPn 500. (A) Evolution of the Ln([M]0/[M]) as a function of time. (B) Evolution of the particle size as a function of time. (C) Evolution of the measured molar masses as a function of monomer conversion; the dash lines are a guide for the eye. (D) Evolution of the dispersity values as a function of monomer conversion.

  183 copolymers was targeted. THGMA (Tg = -30 ℃) and CDMMA (Tg = 92 ℃) were used for the soft and hard segments, respectively. A macro-initiator of poly(THGMA) was synthesized using Dispolreg 007 in nitroxide mediated miniemulsion polymerization ([M]0/[Dispolreg 007]0 = 225), the reaction was stopped at 98 % conversion with Mn = 50,000 g.mol -1 and Ð = 1.13. Subsequently, a mixture of CDMMA (3.5 g, [M]0/[macro-initiator]0 = 312) and acetone (10 wt% based on monomer) was added to the poly(THGMA) latex and polymerized at 97 ℃ for 8 hours. In this way, the full terpene soft/hard diblock copolymers of poly(THGMA)50000-b-poly(CDMMA)74000 and poly(THGMA)50000-bpoly(CDMMA)27000) were synthesized. The block copolymers prepared are summarized in Table5.5. It should be highlighted that the synthesis of the diblock copolymers in miniemulsion was carried out without using any intermediate purification. This is necessary for industrial implementation.

Figure 5 . 7 .

 57 Figure 5.7. (A) SEC traces and (B) AFM picture of a poly(THGMA)50000-bpoly(CDMMA)74000 soft/hard diblock copolymer via chain extension of poly(THGMA) macro-initiator agent with CDMMA. (C) SEC traces and (D) AFM picture of a poly(THGMA)50000-b-poly(CDMMA)27000 soft/hard diblock copolymer via chain extension of poly(THGMA) macro-initiator agent with CDMMA. The molecular weights were extracted from SEC-MALS analysis using the measured dn/dc value for poly(THGMA) (dn/dc = 0.056 mL.g -1 ) and poly(CDMMA) (dn/dc = 0. 0.089 mL.g -1 ).

  The success of the chain extension of poly(THGMA) macroinitiator with CDMMA is evidenced in Figure5.7. SEC analyses show a shift toward to higher molar masses (97 % conversion, Mn = 124,000 g.mol -1 for poly(THGMA)50000-bpoly(CDMMA)74000 and 89 % conversion, Mn = 77,000 g.mol-1 for (poly(THGMA)50000-b-poly(CDMMA)27000. A monomodal distribution is obtained for the diblock copolymers with relatively low dispersity values. Subsequently, the phaseseparated morphology of poly(THGMA)-b-poly(CDMMA) diblock copolymer was analyzed via AFM. Figures 5.7B and D show two-phase morphologies between soft and hard segments, which consist of the dark and bright domain relative to poly(THGMA) and poly(CDMMA), respectively. Theoretically, as a result of relative percentage of each domain (Table

Figure 5 . 8 .

 58 Figure 5.8. Tan δ as a function of the temperature of the poly(THGMA)-bpoly(CDMMA) soft/hard diblock copolymer.The rheology of the block copolymers was performed using parallel plate geometry with constant strain on a rotational rheometer (TA ARES). Mechanical spectroscopy experiment was performed at frequency 0.1 rad/s over the temperature from 160 to -60 ˚C.

Figure 5 .

 5 8 shows that the poly(THGMA)b-poly(CDMMA) diblock copolymer, presented two distinct glass transition temperatures. The low temperature (-25 ℃ to -29 ℃ ) corresponds to the poly(THGMA) phase and the high one is related to poly(CDMMA). The Tgs of the diblock copolymers are summarized in Table5.5. diblock copolymers of similar molecular weights to those of THGMA/CDMMA, but using styrene instead CDMMA were synthesized to compare the adhesive properties. Poly(THGMA) (10 wt% solids content) was prepared via NMP miniemulsion using Dispolreg 007. The reaction was stopped at 98 % conversion obtaining a polymer with Mn = 50,000 g.mol -1 and Ð = 1.13. Subsequently, without any purification step, styrene (3.5 g, [M]0/[macro initiator]0 = 672 and 1.5 g [M]0/[macro initiator]0 = 288) mixed with the acetone (10 wt% based on monomer) was added to the (THGMA) latex and polymerized at 97 ℃ for 8 hours. After polymerization, soft/hard diblock copolymers (poly(THGMA)50000-b-poly(S)77000 and

Figures 5 . 9 B

 59 Figures 5.9 B and D present the AFM images of the morphology of the

Chapter 5 190Figure 5 . 9 . 3 .Figure 5 . 10 .Figure 5 . 11 .

 5593510511 Figure 5.9. (A) SEC traces and (B) AFM picture of a poly(THGMA)50000-bpoly(styrene)77000 AB diblock copolymer via chain extension of poly(THGMA) macroinitiator agent with styrene. (C) SEC traces and (D) AFM picture of a poly(THGMA)50000-b-poly(styrene)29400 AB diblock copolymer via chain extension of poly(THGMA) macro-initiator agent with styrene.

  for work of adhesion and peel, this does not justify the results obtained in the shear tests.

5 198

 5 terpene-based methacrylates by nitroxide mediated polymerization and their use as pressure sensitive adhesives. First, the ability of an alkoxyamine recently developed in our lab (Dispolreg 007) to control the polymerization of tetrahydrogeraniol methacrylate (THGMA) in solution of toluene was investigated. Good control over the polymerization was obtained up to DPn 200. At higher targeted DPn, formation of macromonomer was observed, which led to a reduced molar mass compared to the targeted value. When the process was carried out in miniemulsion, excellent control over the polymerization of THGMA could be achieved up to DPn 500 and narrow molecular weight distributions at high conversion were obtained. The improvement was attributed to the fast recombination of the radical and the nitroxide in the confined environment of the polymer particle. Terpene-based soft/hard diblock copolymers were synthesized starting with a THGMA macroradical with varying the molecular weight of hard polymer (CDMMA). Diblock THGMA-S copolymers were also synthesized for comparison purposes. SEC showed a successful chain extension in all cases, although the increase in dispersity indicated the presence of a small fraction of dead chains. Well-defined phase-separation between soft and hard polymers were observed.ChapterThe adhesive properties of the diblock copolymers were evaluated with probe tack, peel strength and shear resistance. It was found that migration of the short polymer chains could affect the shear resistance. The adhesive performance of the fully bio-sourced PSAs was comparable to the partially petroleum-based styrene systems and better than that found for the acrylates-based triblock copolymers in Chapter 4.Chapter 6. ConclusionsThis PhD thesis aims at contributing to the reduction of the petroleum dependence by producing polymers using monomer obtained from bio-sourced terpenes. The terpenes are side products of the local paper industry created around the "Landes" pine forest in the South West of France. Tetrahydrogeraniol (THG) and Cyclademol (CDM) were chosen as terpene derivatives to prepare (meth)acrylic monomers that can replace its petroleum-based homologues n-butyl acrylate, 2ethylhexyl acrylate, methyl methacrylate and styrene. A synthetic method for the efficient production of several terpene-containing (meth)acrylates (tetrahydrogeraniol acrylate (THGA), tetrahydroheranoiol methacrylate (THGMA), cyclademol acrylate (CDMA) and cyclademol methacrylate (CDMMA)) was developed. These monomers were polymerized in bulk, solution and aqueous dispersed systems by free radical polymerization, RAFT polymerization and nitroxide mediated polymerization (NMP). Chapter 6 208 THGA was first polymerized in toluene and bulk via free-radical polymerization, achieving high conversions and molecular weights up to 278 kg•mol -1 . The synthesized poly(THGA) showed a relatively low Tg (-46 °C), making it useful as a replacement for low Tg acrylic monomers, such as the widely used n-butyl acrylate. RAFT polymerization of THGA in toluene ([M]0 = 3.6 mol.L -1 , [CTA]0/[I2]0 = 10) led to polymers with degrees of polymerization (DPn) from 25 to 500 and narrow molecular weight distributions (Ð ≈ 1.2) even at high conversions. At lower monomer concentrations ([M]0 = 1.8 mol.L -1 of the control was not that good due to the intramolecular chain transfer to polymer that was demonstrated by detection of branching (arising from the propagation of midchain radicals) and terminal double bonds (arising from β-scission of midchain radicals). Solution polymerization was also used for the successful synthesis of poly(THGA)-b-poly(styrene)-b-poly(THGA) soft/hard/soft and poly(styrene)-b-poly(THGA)-b-poly(styrene) hard/soft/hard triblock copolymers, demonstrating its potential as a component of thermoplastic elastomers.The morphology of the triblock copolymers observed via atomic force microscopy (AFM) revealed the phase separation between the soft and hard segments (poly(THGA) and poly(styrene), respectively). The phase-separation of the triblock copolymers was further confirmed by rheological measurements, where two distinct glass transition temperatures were observed.Conclusions 209However, the synthetic route used is not sustainable as the polymerizations were carried out in solution, namely with an extensive use of solvent. The seek for a more sustainable synthetic method prompted us to polymerize the new monomers in aqueous dispersed media, which is more environmentally friendly. Due to the fact that the biosourced monomers synthesized in this work as well as the control agents used are rather hydrophobic, miniemulsion polymerization was utilized in order to avoid the the need of mass transport through the aqueous phase, which is characteristic of emulsion polymerization. As in polymerization in dispersed media the type of initiator strongly affects the polymerization, three different initiators were tested: the oil-soluble AIBN that produces radicals in the polymer particles, the water-soluble potassium persulfate that forms highly hydrophilic radicals in the aqueous phase, and the redox couple (TBHP/AscA) that forms hydrophobic radicals in the aqueous phase. It was found that high conversion was achieved when the polymerization was conducted with the initiators yielding hydrophobic radicals (AIBN and TBHP/AscA). Good control over the RAFT polymerization was achieved, an stable dispersions of poly(THGA) with degrees of polymerization ranging from 50 to 450, relatively low polydispersity values and high conversions were obtained. Terpene-based triblock copolymers were then synthesized by RAFT miniemulsion polymerization. Both hard-soft-hard and softhard-soft triblock copolymers were prepared using poly(THGA) as soft segment and Chapter 6 210 poly(CDMMA) as hard one. These triblocks consist only of terpene derivatives, thus maximizing the use of renewable resources. An important characteristic of the process developed is its scalability as no intermediate purification step after the synthesis of the first block is needed. The nano-phase segregation of the copolymers was observed by AFM and rheological measurements. Finally, the formulations using fully bio-based monomers shown good adhesive performance, in comparison to triblock copolymers partially based on styrene. Block copolymers from bio-sourced terpene-based methacrylates were also successfully synthesized by nitroxide mediated polymerization using the alkoxyamine Dispolreg 007. The NMP of THGMA was first carried out in toluene with good control over the polymerization for degrees of polymerization up to DPn = 200. At higher targeted DPn, evidence of the macromonomer was observed leading to a reduced molar mass compared to the predicted value. When the process was carried out in miniemulsion, excellent control over the polymerization of THGMA could be achieved up to DPn 500 and narrow molecular weight distributions at high conversion were obtained. The improvement was attributed to the fast recombination of the radical and the nitroxide in the confined environment of the polymer particles. Terpene-based soft/hard diblock copolymers were successfully synthesized starting with a THGMA Conclusions 211 macroradical, varying the molecular weight of hard polymer (CDMMA). Diblock

  polimerizó primero en tolueno y en masa mediante polimerización por radicales libres, logrando altas conversiones y pesos moleculares de hasta 278 kg•mol -1 . El poli(THGA) sintetizado mostró una Tg relativamente baja (-46 °C), por lo que es útil como sustituto de los monómeros acrílicos de baja Tg, como el acrilato de n-butilo ampliamente utilizado. La polimerización RAFT de THGA en tolueno ([M]0 = 3.6 mol.L -1 , [CTA]0 / [I2]0 = 10) condujo a polímeros con grados de polimerización (DPn) de 25 a 500 y distribuciones de peso molecular estrechas (Ð ≈ 1.2) incluso a altas conversiones. A concentraciones de monómero más bajas ([M]0 = 1.8 mol.L -1 ) el control no fue tan bueno debido a la transferencia de cadena intramolecular al polímero que se demostró mediante la detección de ramificación (que surge de la propagación de radicales de cadena media) y dobles enlaces terminales (que surgen de la escisión β de radicales de cadena media). La polimerización en solución también se usó para la síntesis exitosa de copolímeros tribloque blando/duro/blando de poli (THGA)-bpoli(estireno)-b-poli(THGA) y tribloque duro/blando/duro poli (estireno)-bpoli(THGA)-b-poli(estireno), demostrando su potencial como componente de elastómeros termoplásticos. La morfología de los copolímeros tribloque observada mediante microscopía de fuerza atómica (AFM) reveló la separación de fases entre los segmentos blandos y duros (poli(THGA) y poli(estireno), respectivamente). La separación de fases de los copolímeros tribloque se confirmó adicionalmente mediante grados de polimerización que varían de 50 a 450, valores de polidispersidad relativamente bajos y altas conversiones. Los copolímeros tribloque a base de terpeno también se sintetizaron mediante polimerización en miniemulsión RAFT. Tanto los copolímeros de tres bloques duro-blando-duros y blando-duro-blando se prepararon usando poli (THGA) como segmento blando y poli (CDMMA) como duro. Estos

  Abbreviations and Acronyms

Table 1 . 1 .

 11 Main terpenoid compound of some essential oils.

	Essential oil	Botanical Name	Main Constituents
	Turpentine	Pinus spp.	Terpenes	(pinenes,
			camphene)
	Coriander	Coriandrum sativum	Linalool (65/80%)

141-143 1.5. Pressure sensitive adhesive (PSA)

	Chapter 1
	relatively long chain acrylates (e.g. 2-ethylhexyl acrylate, n-butyl acrylate) as soft poly(styrene-b-butadiene-b-styrene) (SBS) 159 and poly(styrene-b-isoprene-b-
	monomers, whereas styrene or methyl methacrylate are often utilized as hard styrene). 5, 160 The synthesis of PSAs using bio-based monomers has been made and
	monomers. 148-150 These are petroleum-based monomers. To alleviate the dependency PSAs with good mechanical and adhesion properties have been reported. 161-166 Thus,
	on petroleum, attempts to use materials from renewable resources have been reported. triblock PSAs were prepared using bio-based acrylic isosorbide (AAI) and glucose
	Renewable materials can be introduced into the adhesive in several ways. The most acrylate tetraacetate as hard monomers and 2-ethylhexyl acrylate (2-EHA) or n-butyl
	evident route is to use natural products that already have an adhesive characteristic such acrylate (BA) as the "soft" monomers. 165, 167 Acrylic monomers obtained from
	as proteins. The second way is to use building blocks or monomers that can be derived depolymerization of lignocellolic biomass have also been used as hard monomers in
	from renewable sources. Biobased acrylated methyl oleate was copolymerized with combination to conventional soft acrylic monomers to produce partially bio-based
	PSAs. 31	commercial methyl methacrylate and ethylene glycol dimethacrylate (EGDMA) to
		produce PSAs. 151, 152 Moreno et al. 153 reported the synthesis of PSAs based on biobased
		methacrylate oleic acid (MOA) and α-methylen-γ-butyrolactone in disperse media.
		Badía et al. 154 carried out the copolymerization of 2-octyl acrylate and isobornyl
		methacrylate to produce the waterborne PSAs.
	Pressure-sensitive adhesives (PSAs) are viscoelastic materials that firmly adhere Block copolymers are an interesting alternative to random copolymers because
	to various surfaces upon applying a gentle pressure. PSAs should have both liquid-like their mechanical properties can be tailor-made by modifying the functionality and the
	viscosity and solid-like elasticity in order to obtain the sticky contact and the resistance length of the blocks. 155-158 In addition, the synthesis of this type of copolymers is readily
	to flow during the separation, respectively. 144-147 Acrylates dominate the waterborne available by controlled radical polymerization. 156 In PSAs, block copolymers are AB
	PSAs market. Typically, acrylic based PSAs are random copolymers that contain and ABA types, where A is a glassy and B is a rubbery segment. The most studied of
		PSAs block copolymers are styrene-based linear ABA triblock copolymers, such as
	36

1.6. Objective of the thesis

	monomers, to replace its petroleum-based homologues n-butyl acrylate, 2-ethylhexyl
	acrylate, methyl methacrylate and styrene. Then, the synthesized bio-based monomers
	are polymerized in bulk, solution and aqueous dispersed systems by free radical
	polymerization, RAFT polymerization and NMP.
	Waterborne PSAs formed by block copolymers are obtained by miniemulsion
	copolymerization of the terpene-based monomers. Hard/soft/hard, soft/hard/soft and
	soft/hard structures are synthesized. The effect of the polymer architecture and
	molecular weight on the adhesive properties are examined. The adhesive performance
	of full terpene di/tri block copolymers is compared with that of block copolymers
	containing some petroleum-based monomer.
	Most synthetic plastics are derived from fossil fuel and their production
	increases every year. As a consequence, fossil resources are being exploited faster than
	they are being replenished. Therefore, the objective of the project is to contribute to the
	reduction of the petroleum dependences by using monomer based on bio-sourced
	terpenes. The bio-based terpenes are side products of the local paper industry of the
	"Landes" pine forest in the South West of France. Tetrahydrogeraniol (THG) and
	Cyclademol (CDM) were chosen as a terpene derivative to prepare (meth)acrylic

1.7. Outline of the thesis In Chapter 2, the presence of the hydroxyl group on the renewable starting material

	THG and CDM is utilized to incorporate a (meth)acrylic functionality. A commercially
	available linear terpene derivative, tetrahydrogeraniol, is utilized to prepare acrylic
	monomer, tetrahydrogeraniol acrylate (THGA) and tetrahydrogeraniol methacrylate
	(THGMA). Cyclademol utilized to prepare the cyclademol acrylate (CDMA) and
	cyclademol methacrylate (CDMMA) is also commercially available.

Table 2 . 1 .

 21 The % yield of terpene monomers.

	Monomer	Yield (%)
	Tetrahydrogeraniol acrylate (by acryloyl chloride)	85
	Tetrahydrogeraniol acrylate (by acrylic acid)	60
	Tetrahydrogeranilol methacrylate (by methacrylic acid)	85
	Cyclademol acrylate (by acrylic acid)	65
	Cyclademol methacrylate (by methacrylic acid)	82

Table 3 . 2

 32

	Entry	[M]0	[I2]0	[M]0/[I2]0	Conv.	𝑀 ̅ n Exp	Ð
		(mol.L -1 )	(mol.L -1 )		(%) a	(g.mol -1 ) b
	1	0.6	1.23×10 -3	516	67	16 200	2.5
	2	1.8	3.50×10 -3	516	80	47 100	2.5
	3	3.6	6.88×10 -3	516	92	69 300	2.8
	4	bulk	9.45×10 -3	516	99	278 000	2.4

. Reaction conditions and resulting monomer conversion and molar masses for the free radical polymerization of THGA at 80 °C.

a Calculated from 1 H NMR. b Extracted from SEC-MALS analysis using the measured dn/dc value for poly(THGA) (dn/dc = 0.0678 mL.g -1 ).

Table 3 .

 3

Table 3 . 3 .

 33 Reaction conditions and resulting monomer conversion and molar masses for the RAFT polymerization of THGA at 80 °C.

	Entry	[M]0	[M]0/	[DBTTC]0/	Conv.	𝑀 ̅ n Theor	𝑀 ̅ n Exp	Ð
		(mol.L -1 )	[DBTTC]0	[I2]0	(%) a	(g.mol -1 ) b	(g.mol -1 ) c
	5	0.6	250	2	33	16 800	18 300	1.9
	6	1.8	250	2	75	37 800	27 300	1.9
	7	3.6	250	2	92	46 400	36 000	1.2
	8	Bulk	250	2	97	48 600	35 000	1.8
	9	0.6	250	10	51	26 000	22 000	1.1
	10	1.8	250	10	91	45 500	39 600	1.2
	11	3.6	250	10	94	47 100	50 000	1.1
	12	Bulk	250	10	95	47 600	46 200	1.1
	13	3.6	100	10	96	19 200	22 300	1.1
	14	3.6	50	10	94	9 700	12 000	1.1
	15	3.6	25	20	94 d	5 200	5 700	1.2
	16	3.6	500	10	95 e	93 200	96 500	1.2

a After 6 hours of polymerization, calculated from 1 H NMR. b Calculated using the monomer conversions; initial concentrations [M]0, [DBTTC]0, [I2]0 ; f = 0.5 ; fC = 1 and the value of kD AIBN at 80 °C (see supporting information for details). c Extracted from SEC-MALS analysis using the measured dn/dc value for poly(THGA) (dn/dc = 0.0678 mL.g -1 ). d After 8 hours of polymerization. e After 4 hours of polymerization Chapter 3 98

Table 2

 2

	), [M]0 = 1.8 mol.L -1 at 91 %

The effect of targeted degree of polymerization

  In order to determine the extent of control over the RAFT polymerization of the bio-sourced based monomer, polymerizations were conducted at various target DPns,[M]0/[DBTTC]0 = 25, 50, 100, 250 and 500. The reaction conditions, resulting monomer conversions and molar masses are summarized in Table3.3 entries 11 and 13 to 16. In Figure

4.2.2. Synthesis procedures 4.2.2.1. Preparation of the homopolymer dispersion by RAFT miniemulsion polymerization

	Chapter 4 Chapter 4	Paving the way to sustainable waterborne pressure-sensitive adhesives using terpene-
		based triblock-copolymer
	based on RAFT miniemulsion polymerization of terpene-based monomers and it is
		THGA
	summarized in Scheme 4.1. The article is organized as follows. First, it is demonstrated
	that the RAFT polymerization of terpene-based monomers can be achieved in CDMA
	miniemulsion. Then, bio-sourced hard-soft-hard or soft-hard-soft triblock copolymers S
	that can be utilized as waterborne adhesives are synthesized. Tetrahydrogeraniol
	Scheme 4.1. Reaction scheme to yield functional triblock copolymer based on terpene.
	4.2. Experimental
		4.2.1. Materials
		The materials are given in Appendix Ι
		Therefore, this chapter aims at demonstrating the feasibility of synthesizing
	whole bio-sourced triblock PSAs by an environmentally friendly and waterborne
	process without the need of intermediate purification steps. The synthetic method is
	124 126	125

acrylate (THGA) is employed herein as the "soft" monomer. This monomer has emerged as a robust substitute for BA and/or 2-EHA in the design of thermoplastic elastomers and UV-cured acrylic PSAs.

[19][20][21]

Cyclademol acrylate (CDMA) is introduced as a "hard" monomer, to serve as a substitute to the petroleum-based hard monomers such as styrene and methyl methacrylate. Those terpene-based monomers are later polymerized by RAFT polymerization in miniemulsion to achieve hard-softhard and soft-hard-soft triblock copolymers. The adhesion properties of the triblock bio-based PSAs are then measured and compared with those of a partially bio-based triblock copolymer prepared with THGA and styrene.

Table 4 .

 4

			Organic phase			Aqueous phase
	Entry a	THGA (g)	Initiator	Initiator (mg)	Stearyl acrylate	DBTTC (g)	Water (g)	Dowfax 2A1 (g) c
			type		(g)
	1	10	KPS	25	0.4	0.270	40	0.44
	2	10	KPS	25	0.5	0.270	40	0.66
	3	10	TBHB/AscA	15	0.5	0.270	40	0.66
	4	10	AIBN	15	0.5	0.270	40	0.66
	5	10	AIBN	3	0.5	0.055	40	0.66
	6	10	AIBN	2.2	0.5	0.039	40	0.66
	7	10	AIBN	1.8	0.5	0.030	40	0.66
	8	10	AIBN	10.5	0.5	-	40	0.66

1. Recipes for synthesis the poly(THGA) by RAFT miniemulsion polymerization a 20 wt % solids content. For entry 8, a free radical polymerization was conducted (e.g. in the absence of RAFT agent) with 0.1 wt.% initiator b-o-m. c 45 wt.% active content.

Table 4 . 2 .

 42 Conversion, molar masses and dispersity values of poly(THGA) by RAFT miniemulsion polymerization.

	Entry a [M]0/[CTA]0	[CTA]0/ [I2]0	Time (min)	Conv. (%)	dp (nm)		Np/L latex 10 16 ) (×	Mn,th b 1 ) (g.mol -	Mn,exp c 1 ) (g.mol -	Ð
	2	50	10		300	59	170	7.7	6,400	24,000	1.10
	3	50	10		180	92	170	7.7	9,790	12,800	1.06
	4	50	10		360	94	180	6.5	10,000 11,300	1.10
	5	250	10		360	97	175	7.1	50,400 49,700	1.28
	6	350	10		420	96	230	3.1	69,500 68,500	1.20
	7	450	10		300	96	220	3.6	84,200 82,000	1.15
	8*	n/a	n/a		300	96	208	4.2	-	154,000 1.9
	calculated as 𝑀 𝑛 𝑇ℎ = 𝑀 𝐶𝑇𝐴 +	[𝑀] 0 ×𝑝×𝑀 𝑀 [𝐶𝑇𝐴] 0 +2×𝑓×[𝐼] 0 ×(1-𝑒 -𝑘 𝐷 𝑡 )×(1-𝑓 𝐶 2	)

a Entry 2 conducted with KPS as initiator, Entry 3 conducted with TBHP/Asc as an initiator and AIBN for entries 4-7. For entry 8, a free radical polymerization was conducted (e.g. in the absence of RAFT agent) with 0.1 wt.% AIBN b-o-m. b The theoretical molar masses were

Table 4 . 4

 44

. Rheological properties of the triblock copolymers.

Table 5 . 1 .

 51 Reaction conditions and resulting monomer conversion and molecular weights for synthesis the poly(THGMA) by NMP in toluene.

	Entry a	[M]0	[Dispolreg	[M]0/	T	Conv	Mn,th c	Mn,exp	Ð
		(mol.L -1 )	007]0	[Dispolreg	(ºC)	(%) a	(g.mol -1 ) b	(g.mol -1 ) c
			(mol.L -1 )	007]0
	1	1.95	7.73 x 10 -2	25	90	84	5 130	11 990	1.20
	2	1.95	7.73 x 10 -2	25	95	85	5 190	5 010	1.60
	3	1.95	7.73 x 10 -2	25	97	90	5 500	5 580	1.25
	4	1.95	1.93 x 10 -2	100	97	86	20 600	20 200	1.30
	5	1.95	9.66 x 10 -3	200	97	83	38 200	36 400	1.35
	6	1.95	4.83 x 10 -3	400	97	79	72 000	66 600	1.30
						[𝑀] 0 ×𝑝×𝑀 𝑀
						[𝑎𝑙𝑘𝑜𝑥𝑦𝑎𝑚𝑖𝑛𝑒] 0

a Calculated from 1 H NMR. b 𝑀 𝑛,𝑡ℎ = 𝑀 𝑎𝑙𝑘𝑜𝑥𝑦𝑎𝑚𝑖𝑛𝑒 +

Table 5 . 2 .

 52 Recipes for synthesis the poly(THGMA) by NMP miniemulsion.

	Chapter 5

a 20 wt.% solids content.

Table 5 . 3 .

 53 Recipes for synthesis the soft/hard diblock copolymer.

	Entry macro-initiator	Monomer	Monomer	Acetone
		seed latex		(g)	(10 wt.% b-o-m)
		(g)
	12	25	CDMMA	3.5	0.35
	13	25	CDMMA	1.5	0.15
	14	25	Styrene	3.5	0.35
	15	25	Styrene	1.5	0.15

Table 5 .

 5 Calculated by gravimetry. b 𝑀 𝑛,𝑡ℎ = 𝑀 𝑎𝑙𝑘𝑜𝑥𝑦𝑎𝑚𝑖𝑛𝑒 +

	4. Conversion, molar masses and dispersity values of poly(THGMA) by NMP
	miniemulsion.
	Entry [M]0/[Dispolreg 007]0 Conv. a	dp	Mn,th b	Mn,exp c	Ð
			(%)	(nm)	(g.mol -1 )	(g.mol -1 )
	7	50	97	167	11 340	11 000	1.24
	8	100	90	170	21 220	24 480	1.26
	9	200	93	178	43 570	42 430	1.28
	10	400	90	170	80 970	81 720	1.37
	11	500	78	170	89 390	93 390	1.31
					[𝑀] 0 ×𝑝×𝑀 𝑀
					[𝑎𝑙𝑘𝑜𝑥𝑦𝑎𝑚𝑖𝑛𝑒] 0

a

Table 5 .

 5

	terpene-based soft/hard copolymers.
	of
	5. Preparation

Table 5 .

 5 6 also shows that the fully bio-sourced PSAs compared well with the

	PSAs containing S, which opens the possibility to substitute petrol-based monomers by
	bio-sourced ones.

Table 5 . 6 .

 56 Adhesion properties of soft/hard diblock copolymers.

	Block copolymer	Work of	Peel	Shear	Type
		adhesion	(N/25mm)	resistance	of failure
		(J/m 2 )		(min)
	Poly(THGMA)50000-b-	85±5.6	13± 0.2	25± 0.7	Adhesion
	poly(CDMMA)74000
	Poly(THGMA)50000-b-	132±11	9 ± 1.4	35± 1.5	Adhesion
	poly(CDMMA)27000
	Poly(THGMA)50000-b-	65±6.7	24 ± 2.3	18± 2.5	Adhesion
	poly(S)77000
	Poly(THGMA)50000-b-	96±11	17± 0.3	25± 3.
	poly(S)29400

mediciones reológicas, donde se observaron dos temperaturas de transición vítrea distintas.Sin embargo, la ruta sintética utilizada no es sostenible ya que las polimerizaciones se llevaron a cabo en solución, es decir, con un uso extenso de disolvente. La búsqueda de un método sintético más sostenible nos llevó a polimerizar los nuevos monómeros en medios dispersos acuosos, que son más ecológicos. Debido al hecho de que los monómeros de origen biológico sintetizados en este trabajo, así como los agentes de control utilizados, son bastante hidrófobos, se utilizó la polimerización en miniemulsión para evitar la necesidad de transporte de masa a través de la fase acuosa, que es característica de la polimerización en emulsión. Como en la polimerización en medio disperso el tipo de iniciador afecta fuertemente la polimerización, se probaron tres iniciadores diferentes: el AIBN soluble en la fase orgánica que produce radicales en las partículas de polímero, el persulfato de potasio, soluble en agua que forma radicales altamente hidrófilos en la fase acuosa, y el par redox (TBHP/AscA) que forma radicales hidrófobos en la fase acuosa. Se encontró que se logró una alta conversión cuando la polimerización se realizó con los iniciadores produciendo radicales hidrófobos (AIBN y TBHP/AscA). Se logró un buen control sobre la polimerización RAFT, se obtuvieron dispersiones estables de poli (THGA) con

Acknowledgements I would like to express my sincere gratitude to my supervisors Prof. José M. Asua, Prof. Laurent Billon and Dr. Alexandre Simula for their valuable guidance, support, encouragement and patience. It was a precious opportunity for me to work under their supervision. I would like to extent my gratitude to the professors of the Chemical Engineering Group, Professors Jose R. Leiza, Maria Paulis, Maria J. Barandiaran, Alejandro J. Müller, David Mecerreyes and Dr. Nicholas Ballard, and the professors from the Equipe de Physique et de Chimie des Polymères" (EPCP) in France, Professors Stéphanie Reynaud, Maud Save and Christine Lartigau-Dagron for their insightful comments and encouragement in the seminars. I would like to show my gratitude to Inés Plaza for her endless help and support in every aspect. I would like to thank former and current members of our research groups in Polymat and EPCP for creating a nice research environment full of joy, learning and scientific discussions. I would like to acknowledge the Dérivés Résiniques Terpéniques (DRT, France) for kindly supplying the starting materials. I would like to thank Dr. José Ignacio Miranda from SGIker and Abdel Khouh from EPCP for their assistance in the NMR measurements, Virginie Pellerin for AFM analysis, Dr. Mercedes Fernandez and Dr. Xavier Callies for the technical support and discussion in rheology analysis.

Me gustaría agradecer a mi familia española (Adrian, Floren, Damian y Merche) y tailandesa en San Sebastián, que siempre me ayudan cuando lo necesito, que me recordó a mi hogar y estuvo a mi lado, y gracias a Floren por su comida.

The DSC thermogram of homopoly(THGMA) (Mn = 5,500 g.mol -1 ) is presented in Figure 5.2, showing low glass transition temperature (Tg) approximately -30 ℃. It should be noted that this Tg is higher than that of tetrahydrogeraniol acrylate (THGA) ( Tg = -46 ℃) used in Chapter 4. This is likely due to the presence of the methyl group in the chain backbone of poly(THGMA) resulting in a higher steric hindrance to the segmental rotation, leading to an increase of stiffness chain that results in a higher Tg. 34 5.1 (entries 3 to 6). As expected, the rate of polymerization increased by decreasing the degree of polymerization, due to the higher radical concentration (Figure 5.3A). Figure 5.3B shows that the molecular weights linearly increased with conversion and that relatively low dispersity indexes were obtained when DPn from 25 to 200 were targeted. On the other hand, at higher targeted DPn (DPn = 400), the molar masses slightly deviated from the theoretical line at high monomer conversions. This might be due to the occurrence of the undesired chains such as the termination by disproportionation between the nitroxide and propagating radical and the bimolecular termination of radical species that for methacrylates occurs by disproportionation. 22,35,36 All these events yield an unsaturated end group, i.e. often called macromonomer, and result in the decrease of molecular weight as well as the broadening of dispersity, which is commonly observed in the polymerization of methyl methacrylate in NMP system.

I.2. Monomer conversion

Solution polymerization

Monomer conversion was calculated from

Miniemulsion polymerization

The monomer conversion in dispersed media was calculated by gravimetric. The samples withdraw from the rector (1 ml of latex) at each time interval were placed in an aluminium cup contained of 1 wt% of hydroquinone water solution and dried in an oven (60 ℃) for overnight.

I.3. Theoretical molar masses

RAFT polymerization at 80 ℃

The theoretical molar masses (for Chapter 3) were calculated using equations 1 and 2 using kD AIBN@65 °C = 1.9254×10 -5 s -1 , the activation energy of AIBN Ea = 132 kJ.mol -1 , R = 8.314 J.mol -1 .K -1 , f the initiator initiation efficiency f = 0.5 and assuming termination by combination only (fC = 1).

𝑘 𝐷 𝐴𝐼𝐵𝑁 @ 80 𝐶 = 𝑘 𝐷 𝐴𝐼𝐵𝑁 @ 65 𝐶 × 𝑒 -𝐸𝑎 𝑅 (

) = 1.42 × 10 -4 𝑠 -1

(1)

Where [M]0, [CTA]0, [I]0 are the initial concentrations of monomer, chain transfer agent (CTA) and initiator respectively; MM, MCTA the molar masses (in g.mol -1 ) of the monomer and CTA respectively and p the monomer conversion at a time t (in seconds).

Appendix Ι

230

RAFT polymerization at 70 ℃

The theoretical molar masses (for chapter 4) were calculated as

where [M]0, [CTA]0, [I]0 are the initial concentrations of monomer, chain transfer agent (CTA) and initiator respectively; MM, MCTA the molar masses (in g.mol -1 ) of the monomer and CTA respectively and p the monomer conversion at a time t (in seconds);

f the initiator initiation efficiency f = 0.5 and assuming termination by combination only (fC = 1) and 𝑘 𝐷 𝐴𝐼𝐵𝑁 = 4.47 × 10 15 × 𝑒 -𝐸𝑎/𝑅𝑇 (𝑠 -1 ).

NMP at 97 ℃

The theoretical molar masses (for chapter 5) were calculated as

Appexdix Ι

231

Where [M]0 is the initial concentrations of monomer; Malkozyamine, MM the molar masses (in g.mol -1 ) of the alkoxyamine and monomer, respectively and p the monomer conversion

I.3. Branching and macromonomer fractions

The branching fraction is calculated as % Branching =100 × ∫ Cq / (∫ Cq + ∫ CHt).

The methyl group was used instead of the tertiary carbon in the backbone.

The macromonomer fraction was calculated by 1 H-NMR from the ratio of the sum of the integral from hydrogens from the macromonomer at shifts of δ = 6.13 and δ = 5.57 ppm to the OCH2 δ = 4.25 ppm peak. The β-scission content is calculated as % β-scission = 100 × ∫ H2C=C / ∫ OCH2.

I.4. Miniemulsion stability

The miniemulsion stability was investigated by studying the evolution of the dn/dc = 0.0678 mL.g -1 , dn/dc for poly(THGMA) = 0.056 mL.g -1 , dn/dc for poly(CDMA) = 0.0997 mL.g -1 , dn/dc for poly(CDMMA) = 0.0897 mL.g -1 and dn/dc for poly(styrene) = 0.187 mL.g -1 . All samples were passed through 0.45 µm nylon filter before analysis. The absolute molar masses were calculated from the MALS/RI data using the Debye plot (with the 1st order Zimm formalism).

I.6. Nuclear Magnetic Spectroscopy (NMR)

NMR spectra were recorded at 25 ℃ in CDCl3 at concentration of 350 mg.mL -1 on a DPX-400 or a DPX-500 Spectrometer. 1D 1 H spectra were acquired by use of 32K

Appexdix Ι 235 data points, which were zero-filled to 64K data points prior to Fourier transformation.

1D 13 C spectra were recorded at a 13 C Larmor frequency of 125.77 MHz. The spectra were recorded using 20,000 transients. Quantitative 13 C spectrum were recorded using single pulse excitation, using 5.5 μs 90˚ pulse, inverse gated waltz16 decoupling to avoid NOE effects, and relaxation delay of 5 s. Apodization was achieved using an exponential window function equivalent to a line width of 5 Hz. DOSY(diffusion ordered spectroscopy) were recorded using pulse sequence dstebpgp3s.

I.7. Atomic Force Microscopy (AFM)

Atomic force microscopy (AFM) was performed on Multimode 8 Atomic Force Microscope a (Bruker) and recorded in PeakForce QNM mode. The polymer film was obtained by spin coating of a diluted polymer solution (3 wt.% in toluene) onto a silicon wafer.

I.8. Rheological measurement

Samples for the rheological experiment were prepared as follow; the latex was deposited in the silicone molds and dried at room temperature. The volume of latex was calculated to give the required final film thickness which depending on the latex solid Appendix Ι 236 content. Then, the dried sample was cut to the desired dimension. The linear viscoelastic of the block copolymers was performed using parallel plate geometry with constant strain on a rotational rheometer (AR2000, TA Instrument). Mechanical spectroscopy experiment was performed at frequency 0.1 rad/s over the temperature from 150 to -60 ˚C. Frequency sweeps (0.001 -10 Hz) with applied strain 1 to 5 %, the characterization was performed at room temperature.

Appendix Ⅱ II.1. Adhesion

The science of adhesion is the study of the interactions between two solid surfaces, the energy needed to separate both surface and of the deformation mechanism occurring during the adhesion test. 1 Peel adhesion, shear resistance and tack are the basic properties that have to be optimized for the PSA material. Peel is the characterized by measuring the force required to remove a PSA from the substrate and shear resistance is defined by the resistance of the adhesive to failure in the direction parallel to the interface. Tack is the capacity to stick instantaneously to a substrate by simple contact. A high tack requires a high level of molecular mobility at the interface at frequencies of the order of sticking time. Peel requires a highly dissipative behavior at high shear rates. There two properties are optimal for a very viscous liquid. However, good resistance to shear over long times requires a good resistance to creep and is optimal for elastic solid. Hence, viscoelastic materials are needed for a good compromise in properties between tack, peel and resistance to shear.

Ⅱ.1.2. Shear resistance

The shear strength is the internal or cohesive strength of adhesive. Generally, it measures the holding power test and it is determined as the time require for standard strip of PSA to fall from a test panel after application of a load. The adhesive films were prepared by casting the latex over a flame-treated polyethylene terephthalate (PET) sheet (29 μm thick) using a gap applicator with reservoir. A gap of 200 μm was

Ⅱ.1.2. Probe tack

The probe tack test consist in putting the surface of the solid probe into contact with a thin adhesive layer coated on a rigid substrate and measuring the force required to detach it from the adhesive. In this work, the adhesive film were tested on a TA.HD Plus Texture Analyzer (Texture Technologies, Hamilton, MA).

Abbreviations and Acronyms

AA