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

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). T-d5% and T-g 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.