Nouveaux polyéthers et polyesters à base d'isosorbide: synthèse et caractérisation

Reductive Hydroformylation of Isosorbide Diallyl Ether

Isosorbide and its functionalized derivatives have numerous applications as bio-sourced building blocks. In this context, the synthesis of diols from isosorbide diallyl ether by hydrohydroxymethylation reaction is of extreme interest. This hydrohydroxymethylation, which consists of carbon-carbon double bonds converting into primary alcohol functions, can be obtained by a hydroformylation reaction followed by a hydrogenation reaction. In this study, reductive hydroformylation was achieved using isosorbide diallyl ether as a substrate in a rhodium/amine catalytic system. The highest yield in bis-primary alcohols obtained was equal to 79%.

Renewable Polyethers via GaBr3 -Catalyzed Reduction of Polyesters

Herein, a novel approach is reported for the synthesis of medium- and long-chain aliphatic polyethers 2 based on the GaBr₃ -catalysed reduction of polyesters 1 with TMDS as the reducing agent. Thus, various linear and branched aliphatic polyesters 1 were prepared and systematically investigated for this reduction strategy, demonstrating the applicability and versatility of this new polyether synthesis protocol. Medium- and long-chain chain polyethers were obtained from the respective polyesters without or with minor chain degradation, whereas short-chain polyesters, such as poly-l-lactide 1 i and poly[(R)-3-hydroxybutanoate] 1 j, showed major chain degradation. In this way, previously unavailable and uncommon polyethers were obtained and studied.

Structural deformation phenomenon of synthesized poly(isosorbide-1,4-cyclohexanedicarboxylate) in hot water

Water induced deformation phenomena of synthesized polyester including isosorbide shares analogous mechanism of solvent induced crystallization. This structural deformation is effected by pH, open-ring ISB and ester hydrolysis.

LC-polyimides 24. Cholesteric copoly(ester-imide)s derived from 4-aminobenzoic trimellitimide and isomannide or 1,3-butanediol

Two homopoly(ester-imide)s and a series of copoly(ester-imide)s were prepared by polycondensation of N-(4'-carboxyphenyl)trimellitimide dichtoride with isomannide and phenylhydroquinone. A new synthetic method was successfully tested, based on the cocondensation of silytated isomannide and silylated phenylhydroquinone. Furthermore, two copoly(ester-imide)s derived from phenylhydroquinone and (S)-1,3-butanediol were prepared. The copolyesters are non-crystalline. Those rich in chiral diols form an isotropic melt, whereas those containing more than 50mol% of phenyihydroquinone form a liquid-crystalline melt. The formation of a 'Grandjean texture' was never observed.

LC-polyimides 26. Photoreactive, nematic or cholesteric poly(ester-imide)s derived from 4-aminocinnamic acid trimellitimide, isosorbide and various diphenols

A photoreactive and mesogenic dicarboxylic acid was prepared from 4-aminocinnamic acid and trimellitic anhydride. Its dichloride was polyeondensed with isosorbide and methylhydroquinone, phenylhydroquinone, 4,4'-dihydroxydilhenylether or 1.644'-dihy-droxyphenoxy)hexan. The copolyesters containing < 50 mol% of isosorbide form a cholesteric melt and the homopolyesters of the diphenols are nematie. WAXD powder patterns and DSC measurements agree in that all four homopoly(ester-imide)s are semicrystalline. Incorporation of isosorbide reduces and finally eliminates the crystallinity. The solid state of these copoly(ester-imide)s is a cholesteric glass. Copolyesters containing phenylhydroquinone and 5-10 mol% of isosorbide exhibit a Grandjean texture above 250C. The poly(ester-imide)s of unsubstituted diphenols undergo thermal cross-linking above 350C and all poly(ester-imide)s are sensitive to photocross-linking upon irradiation at wavelengths <360 nm.

Optimized Synthesis According to One-Step Process of a Biobased Thermoplastic Polyacetal Derived from Isosorbide

This paper describes both the synthesis and characterization of a biobased and non-aromatic polyacetal produced from the reaction between isosorbide and methylene chloride. The reaction was conducted in an aprotic dipolar and harmless solvent using a one-step, fast and economical procedure. The chemical composition of this polymer was investigated using Nuclear Magnetic Resonance and Fourier Transform Infra-Red spectroscopies. The molecular weights were examined by size exclusion chromatography and MALDI-TOF spectrometry. The synthesis conditions (concentration, mixing speed, solvent nature, stoichiometry, addition mode of one reactan) were found to strongly influence both polymer architecture and reaction yield. Under moderated stirring conditions, the polyacetal was characterized by a larger amount of macro-cycles. Inversely, under higher intensity mixing and with an excess of methylene chloride, it was mainly composed of linear chains. In this latter case, the polymeric material presented an amorphous morphology with a glass transition temperature (Tg) close to 55 °C. Its degradation temperature was evaluated to be close to 215 °C using thermogravimetry according to multi-ramp methodology. The chemical approach and the physicochemical properties are valuable in comparison with that characteristic of other isosorbide-based polyacetals.

Co- and Terpolyesters Based on Isosorbide and Succinic Acid for Coating Applications: Synthesis and Characterization

Co- and terpolyesters based on succinic acid and isosorbide in combination with other renewable monomers such as 2,3-butanediol, 1,3-propanediol, and citric acid were synthesized and characterized. Linear polyesters were obtained via melt polycondensation of nonactivated dicarboxylic acids with OH functional monomers. Polymer end functionality (i.e., hydroxyl or carboxylic acid) was controlled by adjusting the monomer stoichiometry. The glass transition temperatures of the resulting polyesters could be effectively adjusted by varying the polymer composition and molar mass. By adding polyfunctional monomers such as trimethylolpropane or citric acid, polyesters with enhanced functionality were obtained. These biobased polyesters displayed functionalities and Tg values in the appropriate range for (powder) coating applications. The polyesters were cross-linked using conventional curing agents. Coatings from branched polyesters--hydroxyl as well as acid functional--showed significantly improved mechanical and chemical resistance compared to those formulated from linear polymers. These renewable polyesters proved to be suitable materials for coating applications with respect to solvent resistance, impact resistance, and hardness.