Chemically recyclable bio-based polyester composed of bifuran and glycerol acetal

Abstract

Bio-based polymer alternatives to general-purpose polymers require new bio-based building blocks. The bifuran structure can be prepared from inedible biomass, and glycerol is manufactured as a byproduct. In this study, we constructed bifurylidene bis(glycerol acetal) (BFG)—composed of the bifuran and glycerol acetal structures—as a fully bio-based building block. Because the glycerol acetal formed five- and six-membered rings, with optical isomers and stereoisomers, BFG is a mixture of 22 isomers. BFG was polymerized with succinic anhydride to form poly[bifurylidene bis(glycerol acetal) succinate] (PBFGS). Td5% and Tg values for PBFGS were higher than those for poly(bifurfurylene succinate) (PBFS), in which the acetal structure is replaced with CH2, indicating that the acetal structure enhances the thermal properties of the polyester. Furthermore, the acetal-exchange reaction of PBFGS, to recover BFG, and the acid hydrolysis of poly[bifurylidene bis(glycerol acetal) dicarboxylate] (PBFGD), to recover bifurfural, a reactant of BFG, were successful, indicating that the introduction of the glycerol acetal structures endowed the bifuran-containing polymer with recyclability.