Thesis--Case Western Reserve University, 2009 / Available online via the OhioLINK ETD Center

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.

We have prepared a new class of polybenzoxazine based nanocomposites through DNA-like self-complementary multiple hydrogen bonding. At first, benzoxazine containing thymine (Bz-T), PEO containing adenine (PEO-A) group and POSS containing adenine (POSS-A) have been successfully synthesized, respectively. Those chemical structures were confirmed by 1H and 13C NMR and FT-IR spectroscopies. DSC and TGA analyses showed that the Bz-T had lower cross-link temperature and higher thermostability than benzoxazine containing methyl acrylate (BZ-ac) group. Moreover, TEM and WAXD provided a new evidence for linearly structure and self-assembly polybenzoxaine through self-complementary multiple hydrogen bonding of its T units. Then, PEO-A/PBz-T and POSS-A/PBz-T hybrid materials were prepared. SAX, WAXD, TEM and AFM analyses indicated that the size of PEO domain in PBz-T matrix was significantly decreased and the new type phase separation boundary (discrete domain through non-convent bonds) was obtained. Finally, we were using WAXD, TEM, DSC and nanoindenter to study properties of POSS-A/PBz-T nanocomposite. The presence of self-assembly nano-lamellate structure and enhance the mechanical properties on thin film, because of well-dispersion of POSS in PBz-T matrix through strong hydrogen bonding between A-T interactions.

No description available.

Differential scanning calorimetry (DSC), 13C solid state nuclear magnetic resonance (SSNMR), one- and two-dimensional fourier transform infrared spectroscopes (FT-IR), Gel Permeation Chromatography (GPC) have been used to investigate the miscibility behavior and specific interactions of Poly(3-hydroxybutyrate), (PHB) blending with poly(styrene-co-vinyl phenol), (PS-co-PVPh) through hydrogen bonding complex upon varying the vinyl phenol contents in copolymer. We describe FT-IR spectra reveal that hydrogen bonding between carbonyl and phenol. A miscibility window exists when the vinyl phenol fraction in the copolymer is greater than 20 mol% in the PHB/PS-co-PVPh blend system, as predicted using the Painter¡VColeman association model. The vinyl-terminated benzoxazine (VB-a), which can be polymerized through ring opening polymerization, was synthesized through the Mannich condensation of bisphenol A, formaldehyde, and allylamine. This VB-a monomer was then blending with epoxy resin, followed by thermal curing concurrently, to form epoxy/VB-a copolymers network. To understand the curing kinetics of this epoxy/VB-a copolymer, dynamic differential scanning calorimetry measurements were performed by Kissinger and Flynn-Wall-Osawa methods. The FTIR analyses revealed the presence of thermal curing reactions and hydrogen bonding interaction of epoxy/VB-a copolymers. Meanwhile, the significant enhancement of the ring opening and allyl polymerizations of the epoxy was observed. For these IPNs, DMA and TGA results indicate that the thermal properties increase with the increase of VB-a contents in epoxy/VB-a copolymers.

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Zugl.: Oldenburg, Univ., Diss., 2008

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