Sweet polymers: Synthesis and characterization of xylitol-based

Abstract

Novel xylitol-functionalized epoxidized linseed oil (ELO) polyols were synthesized. Epoxidized linseed oil obtained by a chemoenzymatic method was first reacted with xilitol by a nucleophilic opening of the epoxy rings with one of the primary hydroxyl groups from xylitol, reaching a partial 50% (ELO-Xyl-50%) and a complete 100% (ELO-Xyl-100%) functionalization. Using N-methyl-2-pyrrolidone (NMP) as the solvent, the ZnCl2 catalyst amount, time and temperature were studied to achieve these functionalizations. Fully bio-resourced polymers were obtained by thermal curing in which the ELO-Xyl- 50% monomer was crosslinked by a reaction between epoxy residues (50%) and the primary hydroxyls of pendant xylitol at 180 C for 90 min, whereas the ELO-Xyl-100% monomer was mixed with ELO in stoichiometrically molar proportions and cured at 200 C for 120 min. All of the structures were characterized by 1H NMR, FT-IR, DSC and TGA. The effect of the xilitol functionalization in monomers was evidenced by their viscosity, where as for polymers, the dielectric constant was evaluated.