Chemosynthesis and characterization of fully biomass-based copolymers of ethylene glycol, 2,5-furandicarboxylic acid, and succinic acid

Poly(ethylene 2,5-furandicarboxylate-co-ethylene succinate) (PEFS) copolymers of 2,5-furandicarboxylic acid (FDCA) and succinic acid with 11.98-91.32 mol % FDCA composition were synthesized via melt polycondensation in the presence of ethylene glycol using tetrabutyl titanate as a catalyst. PEFSs' molecular weight, thermal properties, and molar composition were determined by Fourier transform infrared spectroscopy, gel permeation chromatography, intrinsic viscosity, ¹H NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and wide-angle X-ray diffraction (WAXD) measurements. From experimental conditions, we obtained random copolymers with number-average molecular weights exceeding 25,600, determined by GPC and ¹H NMR analyses. DSC analysis revealed that PEFS copolymers' melting temperatures differed depending on EF units' percentage. TGA studies confirmed that all PEFS copolymers' thermal stability exceeded 300°C. From WAXD analysis, it is observed that the PEFS copolymer crystal structure was similar to that of PES when EF unit was 11.98 mol % and to that of PEF when EF units were 74.35 and 91.32 mol %. These results benefit this novel biodegradable copolymer to be used as a potential biomaterial.