Ces travaux de thèse concernent l’étude de matériaux supramoléculaires en vue de générer de nouveaux élastomères silicones auto-cicatrisants. Dans un premier temps, l’étude de la bibliographie a permis de recenser les différentes voies intégrant de la chimie supramoléculaire développées dans le domaine des silicones et basées sur les liaisons hydrogène. L’effet des groupements associatifs sur les propriétés rhéologiques et mécaniques des matériaux a été discuté, et les limitations de ces systèmes soulignées. La chimie développée par l’équipe du Dr. Leibler, adaptée par la suite aux silicones par le Pr. Zhang et son équipe, a particulièrement été analysée lors de notre étude de compréhension. Les relations structures/propriétés n’étaient pas clairement élucidées à l’issue de cette étude de la bibliographie. Des études modèles impliquant un PDMS téléchélique aminé ainsi que de l’urée ont donc été réalisées. La caractérisation précise des structures des produits de réaction a permis de mettre en exergue certaines corrélations entre structures (choix du groupement associant, masse molaire du copolymère, fonctionnalité) et propriétés (rhéologiques et mécaniques) qui n’avaient alors pas été démontrées pour ces systèmes. Il a aussi été montré que la force des groupements et les enchevêtrements jouent un rôle primordial. Une chimie différente, inspirée des travaux de Yilgör et al sur les copolymères segmentés, a par la suite été envisagée, en mettant en jeu cette fois la réaction d’aza-Michael. Cette synthèse se démarque du premier système par un meilleur contrôle de la structure macromoléculaire finale. Un silicone supramoléculaire élastomère et auto-cicatrisant a été obtenu en combinant une fonctionnalité importante et une masse molaire finale élevée. Les propriétés mécaniques de ce polymère ont été optimisées par l’ajout de charges plus ou moins renforçantes. L’impact d’un tel renfort sur les propriétés auto-cicatrisantes du système a été discuté. / This PhD thesis focused on the investigation of supramolecular materials in order to generate new self-healing supramolecular silicone elastomers. Firstly, a literature review on silicone materials was realized and we identified the different ways developed in the silicone domain that imply supramolecular chemistry and in particular hydrogen-bonds. The influence of associating groups on rheological and mechanical properties of these materials was discussed, and the restrictions of such systems were highlighted. The chemistry developed by Dr. Leibler and co-workers, later adapted to silicones by Pr Zhang and his team, was deeply investigated during our comprehension study. Relationships between structure and properties were nonetheless not fully elucidated in these studies. Model reactions involving telechelic amino-PDMS and urea were then carried out. The thorough characterization of the final structure of the reaction products highlighted few correlations between structural parameters (choice of the type of associating group, molecular weight of copolymer, functionality) and properties (rheological and mechanical) that had not been demonstrated yet for these systems. We showed that, among others, the strength of the associating groups as well as the entanglements play a fundamental role. A different chemistry, inspired by Yilgör and co-workers’ studies on segmented copolymers, was later considered by carrying out an aza-Michael reaction. This synthesis differs from the previous one by its better control of the final macromolecular structure. A supramolecular silicone elastomer with self-healing abilities was obtained by combining a large functionality together with a high final molecular weight. Mechanical properties of this material were further enhanced through the addition of more or less reinforcing fillers. The influence of such reinforcement on self-healing capacity of this system was discussed.

Facile monomer synthesis provided routes towards novel step-growth polymers for emerging applications. Adjustment of reaction conditions enabled green synthetic strategies, and promising scalability studies offered impetus for industrial funding. Engineering thermoplastics, such as linear polyetherimides (PEIs), had carefully targeted molecular weights for analysis of the effect of molecular weight and regiochemistry on the thermomechanical and rheological properties of PEIs. The design of linear, high performance PEIs comprising 3,3'- and 4,4'-bisphenol-A dianhydride (bis-DA) and m-phenylene diamine (mPD) provided an opportunity to elucidate the influence of dianhydride regiochemistry on thermomechanical and rheological properties. This unique pair of regioisomers allowed the tuning of the thermal and rheological properties for high glass transition temperature polyimides for engineering applications. The selection of the dianhydride regioisomer influenced the weight loss profile, entanglement molecular weight, glass transition temperature (Tg), tensile strain-at-break, zero-shear melt viscosity, average hole-size free volume, and the plateau modulus prior to viscous flow during dynamic mechanical analysis (DMA). The 3,3'-PEI composition interestingly exhibited a ~20 °C higher Tg than the corresponding 4,4'-PEI analog. Moreover, melt rheological analysis revealed a two-fold increase in Me for 3,3'-PEI, which pointed to the origin of the differences in mechanical and rheological properties as a function of PEI backbone geometry. The frequently studied 4,4'-PEI exhibited exceptional thermal, mechanical, and rheological properties, yet the 3,3'-PEI regioisomer lacked significant study in the industrial and academic sectors due to its 'inferior' properties, namely poor mechanical properties. Introduction of long-chain branching (LCB) into PEIs provided a unique comparison between a commercially relevant PEI (Ultem® 1000) and a regioisomer infrequently found in the literature. Thermal stability remained consistent for each regioisomer, and Tgs for the 3,3'- and 4,4'-LCB-PEIs agreed well with prior literature. Rheological analysis demonstrated typical shear thinning and low-shear viscosity trends for LCB systems. The targeted molecular weights for the 3,3'-LCB-PEIs were well below the Me cutoff for "high molecular weight," and for this reason the rheological properties demonstrated inconsistent trends. Further study of PEIs led to the incorporation of ionic endgroups. These provided physical crosslinks, which enhanced mechanical and rheological properties of branched PEIs compared to their non-ionic analogs. The Tgs decreased with an increase in branching concentration for the phenyl-terminated PEI, while it remained unchanged for the ionically-endcapped PEIs. The divalent salts demonstrated higher mechanical strength and melt viscosities compared to the monovalent salt and the non-ionic PEIs. Interestingly, the zinc-endcapped PEI series exhibited decreased high-shear viscosities compared to the other PEIs, lending to promising industrial applications for the zinc-endcapped branched and linear PEIs for high temperature applications. Additional engineering thermoplastics in the form of bio-based polyureas exhibited mechanical properties similar to those of non-bio-based polyureas. The isocyanate-free synthetic route incorporated an essential urea degradation mechanism at elevated temperatures to produce isocyanic acid, which then reacted with amines to produce linear polyurea thermoplastics. Urea provided a sustainable and bio-friendly reagent for high molecular weight, isocyanate-free polyureas. Poly(propylene glycol) triamine enabled the long-chain branching of thermoplastic polyureas. Differential scanning calorimetry (DSC) showed no change in Tg for the series; however, melting peaks decreased in intensity as the branching concentration increased, indicating a reduction in crystallinity. Tensile testing eluded to a decrease in ultimate stress values for higher branching concentrations, while melt rheology showed significant differences in melt viscosities. Viscosities increased markedly with an increase in branching concentration, signifying greater entanglement and stronger physical crosslinks for the branched polyureas. Further analysis of possible isocyanate-free routes led to the use of 1,1'-carbonyldiimidazole (CDI) to generate polyureas and polyurethanes. CDI, known in the literature for its use in amidation and functionalization reactions, enabled the production of well-defined and stable polyurethane monomers. The functionalization of butanediol with CDI yielded an electrophilic biscarbamate monomer, bis-carbonylimidazolide (BCI), suitable for further step-growth polymerization in the presence of amines. The reaction of this novel monomer with aliphatic diamines produced thermoplastic polyurethanes with high thermal stability, tunable glass transition temperatures based on incorporation of flexible polyether segments, and creasable thin films. It is envisioned that CDI functionalized diols will afford access to various polymeric backbones without the use of toxic isocyanate-containing strategies. Additionally, non-isocyanate polyurethane (NIPU) foams were produced from BCI monomers without the need of blowing agents, catalysts, or solvents. These materials offered an alternative to existing foaming technology, which typically employed isocyanates. Polyurethanes were foamed through a CO2 thermal decomposition mechanism involving the BCI monomers. We investigated two series of polyurethane foams with a tunable Tg range from ~0 °C to ~110 °C. We found that the incorporation of aromatic amines vastly altered the foam thermomechanical properties, and the resulting foams were closed-cell in nature. / Doctor of Philosophy / Step-growth polymers play a significant role in commercial and industrial applications. On-going work in this field focuses on sustainability, biodegradability, and improved processability. This dissertation encompasses the improvement and innovation of current and novel engineering thermoplastics and foams. The careful purification and step-growth synthetic strategies herein, afforded targeted molecular weights for analysis of linear and long-chain branched (LCB) polyetherimides (PEIs). Further analysis of LCB-PEIs, with monovalent and divalent ionic endgroups, provided an opportunity to study the effect of ionic interactions and physical crosslinks at high temperatures (>300 °C). The long branches improved the melt processability compared to linear analogues at equivalent molecular weights. The challenge to investigate polyurethanes using non-isocyanate methodologies offered an opportunity to apply fundamental small-molecule, organic synthesis to macromolecular science. 1,1'-Carbonyldiimidazole (CDI) provided a platform to generate polymeric chains from industrially relevant monomers. Additional testing serendipitously discovered the generation of CO2 upon thermal degradation of the novel monomers. Harnessing the release of CO2, during the gelation of polyurethanes, provided an isocyanate-, catalyst-, and solvent-free synthetic route towards polyurethane foams that boasts scalability and industrial relevance.

La polymérisation anionique par activation du monomère permet d’accéder à une large gamme de polyéthers en utilisant un système amorçant à base d’un nucléophile associé au triisobutylaluminium. Cette voie a permis d’accéder à des chaînes polyéthers fonctionnalisées par des groupements hydroxyle à chaque extrémité. La (co)polymérisation de l’éther allylglycidique avec d’autres éthers cycliques a été réalisée puis les (co)polymères correspondants ont été post-fonctionnalisés pour introduire en particulier des fonctions cyclo-carbonate destinées à réagir avec des amines pour générer des fonctions hydroxyuréthane et ainsi préparer des matériaux type polyuréthane par une chimie sans isocyanate. Enfin des dérivés du pin, de la famille des acides résiniques, ont été modifiés chimiquement pour élaborer des matériaux de type résine époxyde et polyuréthane sans isocyanate. La polymérisation anionique par activation du monomère a également pu être réalisée sur un monomère époxydé issu de cette ressource. / Monomer-activated anionic polymerization allows the obtention of versatile polyethers using nucleophilic species in the presence of a Lewis acid, i.e. triisobutylaluminium. This method enables the synthesis of α-,ω-plurihydroxytelechelic polyethers. The (co)polymerization of allyl glycidyl ether with various epoxides allowed the preparation of copolyethers with reactive side groups. A cyclo-carbonate functionalization was carried out in order to introduce hydroxyurethane functions by reaction with amines. This reaction allows the preparation of isocyanate-free polyurethane. Finally, resinic acids were modified chemically to prepare epoxy resins and isocyanate-free polyurethanes. A polyether based on epoxidized resinic derivatives was also synthesized by ring-opening anionic polymerization and monomer activation.

Cette thèse porte sur la synthèse de polyuréthanes thermoplastiques plus durables à partir de dérivés des huiles végétales. La première voie étudiée est basée sur la réaction, largement utilisée, entre un diol et un diisocyanate. Aussi, pour s’affranchir de l’utilisation des diisocyanates toxiques, une approche via la polyaddition entre un bis carbonate cyclique et une diamine a également été étudiée. Pour ce faire des précurseurs bi-fonctionnels : diols, bis carbonates cycliques à 5 et 6 chainons et diamines ont été préparés à partir de dérivés de l’huile de tournesol (oléate de méthyle) et de l’huile de ricin (undécénoate de méthyle et acide sébacique). Les propriétés thermo-mécaniques des polyuréthanes et poly(hydroxyuréthane)s thermoplastiques obtenus ont pu être ajustées par le choix adapté de la structure chimique des précurseurs (gras) utilisés. Les travaux réalisés démontrent un effet de la taille du cycle du carbonate sur la réactivité. En effet, les (bis) carbonates cycliques à 6 chainons se sont avérés plus réactifs que leurs homologues à 5 chainons. De plus, la synthèse de diamines via un intermédiaire dinitrile semble très prometteuse pour le « design » d’une plateforme de diamines issues d’acides gras et de poly(hydroxyuréthane)s entièrement bio-sourcés. / This thesis aims to synthesize more sustainable thermoplastic polyurethanes from vegetable oil derivatives. The first route that has been investigated is based on the well-known reaction between a diol and a diisocyanate. Then to avoid the use of diisocyanates, the route via the polyaddition of a bis cyclic carbonate and a diamine have been studied as well. For this purpose, bifunctional precursors such as diols, bis 5- and 6-membered cyclic carbonates and diamines have been prepared from sunflower oil derivative (methyl oleate) and castor oil derivatives (methyl undecenoate and sebacic acid) The thermo-mechanical properties of the PUs have been modulated by designing and selecting the chemical structure of the (fatty acid-based) monomers. The performed model reaction kinetics revealed the higher reactivity of the 6-membered cyclic carbonates compare to the 5-membered ones. Finally, the developed route to fatty acid-based diamines via dinitriles synthesis in mild conditions was really efficient and this route is really promising to develop a fatty acid based-diamines platform and fully bio-based poly(hydroxyurethane)s.