Récemment, la chimie des ressources renouvelables et les matériaux qui en découlent ont suscités un intérêt considérable dans le but de limiter l’utilisation des ressources fossiles. La présente thèse intitulée « Cardanol : a bio-based building block for new sustainable and functional materials » traite de la modification chimique du cardanol et de son utilisation dans diverses applications. Le cardanol est un dérivé phénolique naturel extrait de l’huile de coque de noix de cajou. Sa structure chimique est intéressante : il est substitué d’une chaîne alkyle en C15, partiellement insaturée, et il est porteur d’une fonction phénol, permettant d’envisager de nombreuses réactions chimiques.La première partie de cette étude traite de la synthèse et de la caractérisation de trois surfactants ammoniums issus du cardanol se différenciant par le degré de substitution de leurs amines. Leur capacité à favoriser l’exfoliation d’une argile lamellaire dans une matrice de type époxy a été étudiée dans le but de concevoir des matériaux composites.Le second chapitre décrit une nouvelle méthode de synthèse de monomères benzoxazines bio-basés et l’élaboration de réseaux polybenzoxazines à partir du cardanol. Une nouvelle génération de monomères benzoxazine, issus du cardanol ou de dérivés de la lignine tels que la vanilline, a récemment été développée. Cependant l’essentiel des benzoxazines bio-basées synthétisées jusqu’à présent sont monofonctionnelles ou présentent des températures de fusion trop élevées. Elles ne permettent donc pas l’élaboration de matériaux autosupportés valorisables. Afin de pallier ce problème, une synthèse originale de monomères benzoxazines asymétriques, reposant sur la combinaison de cardanol et de dérivés de la lignine, est décrite. Les matériaux autosupportés résultants présentent des propriétés améliorées par rapport à celles que ne pourraient atteindre les monomères symétriques issus de ces phénols bio-sourcés.Finalement, le troisième chapitre concerne l’utilisation d’un pré-polymère époxy issu du cardanol pour l’élaboration de matériaux époxy bio-basés. Cependant, en raison de la chaîne alkyle du cardanol, ce nouveau matériau présente une faible Tg et une forte prise en eau. Afin de renforcer ses propriétés thermo-mécaniques et de diminuer sa prise en eau, une modification chimique a été réalisé à l’échelle macromoléculaire par l’élaboration de réseaux interpénétrés de polymères à base de réseaux polybenzoxazines.Ces différents travaux ont permis de mettre en avant la modification aisée et versatile du cardanol, pouvant ainsi résulter en une large variété de synthons bio-basés et des matériaux qui en découlent. Ces travaux ouvrent la voie vers d’autres structures et architectures moléculaires aux applications nombreuses. / Recently, considerable interest of the chemistry of renewable ressources and their resulting materials has grown with a view to reduce the use of finite petroleum-based resources. The present thesis entitled « Cardanol: a bio-based building block for new sustainable and functional materials » is dealing with the chemical modification of cardanol and its use for various applications. Cardanol is a naturally occurring phenolic compound issued from cashew nutshell liquid. Its chemical structure is interesting because cardanol is bearing a phenolic hydroxyl function and an unsaturated alkyl chain in meta. Numerous chemical reactions can thus be considered for its chemical modification.The first part of this study is dealing with the synthesis and the characterization of three cardanol-based ammonium surfactants differing by their amine functionalities content. Their effectiveness on the exfoliation of silicate clay within an epoxy matrix was investigated with the aim to elaborate composit materials.The second chapter is describing a novel method for the synthesis of bio-based benzoxazine monomers and the elaboration of polybenzoxazine networks issued from cardanol. A new generation of benzoxazine monomers issued from cardanol or from lignin derivatives such as vanillin were recently developed. However, up to now, the majority of the synthetised benzoxazine monomers are mainly mono-functionnal or display too high melting temperatures. The elaboration of valuable self-standing materials is thus strongly impeded. To solve this problem, an innovative synthesis of asymmetric benzoxazine monomers by combination of cardanol and lignin derivatives is described. The resulting self-standing materials display improved properties in comparison to materials issued from symmetric bio-based monomers.Finally, the third chapter realtes to the use of a cardanol-based epoxy pre-polymer for the elaboration of bio-based epoxy materials. Nevertheless, this new material displays low Tg and high water uptake due to the alkyle side chain of cardanol. In order to reinforce the thermo-mechanical properties of the material and to reduce its water uptake, a chemical modification was achieved at the macromolecular scale by the elaboration of interpenetrating polymer networks with polybenzoxazine networks.These various studies allowed to highlight the easy and versatile modification of cardanol, resulting thus in a diversity of bio-based synthons and their resulting materials. This work paves the way to the elaboration of other chemical structures and molecular architectures for various applications.

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Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

<p> Poly (dimethyl siloxane) (PDMS) has been widely used as a biomaterial in ophthalmic and other applications due to its good compatibility, high mechanical strength and excellent oxygen permeability and transparency. For use as an artificial cornea, contact lens and in other applications, modifications are necessary to improve glucose permeability and wettability for cell and tear protein and mucin interactions through modification with hydrophilic functional groups or polymers. Poly (N-isopropyl acrylamide) (PNIPAAM) is a biocompatible and hydrophilic polymer that has been extensively studied in controlled drug release applications due to its lower critical solution temperature (LCST) phenomenon. In this study, a composite interpenetrating polymer network (IPN) of PDMS and PNIPAAM was formed to generate material with reasonable oxygen and glucose permeability as well as improved wettability and mechanical properties compared to the PDMS and PNIPAAM homopolymers.</p> <p> Semi-IPNs, with low water uptake and mechanical strength, were found not to be suitable as biomaterials. Vinyl terminated PDMS/PNIPAAM IPNs had reasonable water uptake and excellent tensile stress and strain, but low glucose permeability (< 10^-10 cm^2/s). Hydroxyl terminated PDMS/PNIPAAM IPNs (PDMS-OH IPN) were successfully synthesized with reasonable mechanical properties and significantly higher glucose permeability (~10^-7 cm^2/s). Curing the PDMS-OH film with solvent was found to improve glucose transport.</p> <p> The presence of PNIPAAM in the composite networks was confirmed by FT-IR and Differential Scanning Calorimetry (DSC). Transmission Electron Microscopy (TEM) images verified the structure of interpenetrating networks. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and X-ray Photoelectron Spectroscopy (XPS) suggested that PNIPAAM was also present on the surface and this translated to increased roughness compared with the PDMS control as determined by AFM. The LCST phenomena still remained in the IPN, although the change was not as abrupt as with pure PNIPAAM. These results suggest that the copolymer may be useful as an ophthalmic biomaterial and for controlled drug release applications.</p> / Thesis / Master of Applied Science (MASc)

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The synthesis, characterization and reactivity of linear and network macromolecules by chemical modification of amorphous poly(arylene ethers) with pendant amines were investigated. A new monomer, 3-aminophenyl-bis(4-fluoro phenyl)phosphine oxide was prepared by nitration and reduction of bis(4-fluoro phenyl)phenylphosphine oxide. Statistical incorporation of pendant aryl amines into linear polymers was achieved by copolymerization of the 3-aminophenyl-bis(4-fluorophenyl)phosphine oxide with another activated dihalide monomer such as 4,4'-dichlorodiphenylsulfone and bisphenol-A. Step polymerizations employing nucleophilic aromatic substitution with a dipolar aprotic solvent, toluene as the azeotroping agent, and a slight excess of potassium carbonate as the weak base was the preferred methodology. The concentration of amines along the polymer backbone was successfully controlled by varying the ratio of 3-aminophenyl-bis(4-fluorophenyl)phosphine oxide monomer relative to the other comonomers. Characterization of the pendant amines by proton NMR and potentiometric titration indicated good agreement between the charged amount and the incorporation of this monomer into the copolymer backbone. The pendant amines could be quantitatively converted to pendant phthalimides by reaction with phthalic anhydride. The pendant amines were also reacted to form crosslinkable groups such as maleimides and phenylethynyl phenyl imides. These were thermally treated to induce crosslinking and formed ductile networks which had improved solvent resistance and higher glass transition temperatures. The poly(arylene ethers) containing pendant amines were also reacted with an epoxy resin and 4,4'-diaminodiphenylsulfone to afford epoxy networks which had significant improvement in fracture toughness at selected compositions. Bis(o-aminophenol) monomers were investigated as precursors to poly(arylene ethers) having pendant amines by copolymerization with 4,4'-dichlorodiphenylsulfone and bisphenol-A. These studies resulted in insoluble gels, which suggested that reaction of both the o-aromatic amine and the phenolate with the activated dinalide was occurring. This was further confirmed by the successful oligomerization of o-aminophenol itself with 4,4'-dichloro diphenylsulfone, which afforded NMP soluble novel poly(sec-amino phenoxy diphenylsulfones) with high glass transition temperatures (Tg~276°C). / Ph. D.

Nous avons développé de nouveaux systèmes polymères nanoporeux et fonctionnalisés en vue de leur utilisation comme nanoréacteurs. Deux approches complémentaires ont été envisagées pour la génération des précurseurs nanostructurés des matériaux mésoporeux. La première stratégie repose sur la synthèse de copolymères diblocs poly(D,L-lactide)-bloc-polystyrène (PLA-b-PS) semi-hydrolysable possédant une fonction réactive au point de jonction entre les deux bloc (SO3H) ; la deuxième voie est fondée sur la préparation de réseaux interpénétrés de polymères dont l'un des sous-réseaux est stable et fonctionnalisé (PS) et l'autre est hydrolysable (PLA). L'obtention de la porosité dans ces systèmes organisés a résulté de l'hydrolyse sélective et quantitative des domaines de la phase dégradable. La caractérisation des différents systèmes a été effectuée au moyen de diverses techniques d'analyse fine, telles que des techniques spectroscopiques, la microscopie électronique à balayage, la thermoporométrie par DSC et l'adsorption-désorption d'azote. Ces études physico-chimiques ont permis d'accéder à l'organisation de la porosité et de la chimie de surface, ainsi qu'aux propriétés spécifiques des matériaux nanoporeux. La dernière partie a traité de l'étude des applications potentielles de ces matrices poreuses fonctionnalisées comme nanoréacteurs dans le domaine de la catalyse d'une part, et dans la purification de l'acide phosphorique tunisien, d'autre part / Novel functionalized nanoporous polymer systems have been developed in order to be used as nanoreactors. Two complementary approaches have been envisioned for the generation of the nanostructured precursors of mesoporous materials. The first approach relies on the synthesis of semi-hydrolysable poly(D,L-lactide)-block-polystyrene (PLA-b-PS) diblock copolymers with a functional group (e.g. sulfonic acid) at the junction point between the two blocks, while the second strategy involves the preparation of interpenetrating polymer networks based on a functionalized stable sub-network (PS) and a hydrolyzable one (PLA). The generation of porosity in such organized systems results from the selective and quantitative hydrolysis of domains from the degradable phase. The characterization of different systems has been realized by means of miscellaneous analytical techniques, including spectroscopic techniques, scanning electron microscopy, DSC-based thermoporometry, and nitrogen sorption measurements. Such physico-chemical investigations permitted to get access to the organization of porosity and surface chemistry, as well as the specific properties of nanoporous materials. Lastly, we have investigated the potential applications of these functionalized porous matrices as nanoreactors in the area of catalysis as well as in the purification of Tunisian phosphoric acid

La «chimie verte » comprend le développement de procédés de synthèse respectueux de l'environnement, en réduisant notamment l'usage de solvants organiques. Dans ce but, nous avons montré qu'il était possible de synthétiser, à partir de microémulsions, des matériaux conducteurs protoniques, de structure prédéfinie, sans l'usage d'un autre solvant que l'eau.La première partie de cette étude a permis de démontrer la faisabilité de ce procédé. Le système ternaire choisi est composé d'une solution aqueuse d'acide 2-acrylamido-2-méthylpropane sulfonique (AMPS), de méthacrylate d'hexyle (HMA) comme phase hydrophobe et du tensioactif, le Brij® 35. Les structures des microémulsions ont été identifiées, selon leur composition, à partir de mesures de conductivité, de viscosité et d'imagerie par microscopies optique et confocale. Ces structures peuvent être inverse, lamellaire, bicontinue et directe. La polymérisation/réticulation par voie radicalaire des monomères présents dans les différentes phases conduit à des matériaux présentant ces mêmes structures. Les polymères étant réticulés, ces matériaux sont des réseaux interpénétrés de polymères (RIP).La seconde partie de cette étude a été consacrée à l'optimisation de la formulation des microémulsions pour obtenir des matériaux aux propriétés souhaitées. Ainsi, la fraction soluble et le taux de gonflement dans l'eau ont été considérablement réduits, tout en conservant une conductivité protonique de l'ordre de 10-3 S.cm-1. Les meilleurs résultats ont été obtenus en synthétisant un « double RIP », c'est-à-dire un RIP dans chacune des phases, matériau tout à fait original à ce jour. / "Green chemistry" includes the development of synthetic methods respectful of the environment, including reducing the use of organic solvents. For this purpose, we have shown that it is possible to synthesize, from microemulsions, proton conductive materials, predefined structure, without the use of a solvent other than water. The first part of this study demonstrates the feasibility of this method. The ternary system is selected from an aqueous solution consisting of 2-acrylamido-2-methylpropane sulphonic acid (AMPS), hexyl methacrylate (HMA) as hydrophobic phase and the surfactant, Brij® 35. The structures of microemulsions have been identified, depending on their composition from measurements of conductivity, viscosity and imaging optical and confocal microscopies. These structures can be inverse, lamellar, bicontinuous and direct. The polymerization/crosslinking of the monomers by free radical present in the various phases leads to materials having the same structures. Being crosslinked polymers, these materials are interpenetrating polymers networks (IPN). The second part of this study has been devoted to the optimization of the formulation of microemulsions to obtain materials with desired properties. Thus, the soluble fraction and the degree of swelling in water were significantly reduced, while maintaining proton conductivity of the order of 10-3 S.cm-1. The best results were obtained by synthesizing a "double IPN", that is to say, an IPN in each phase, entirely original material.