New Bio-Based Copolyesters Derived from Novel Cyclic Diol 2,5-Tetrahydrofurandimethanol, 2,5-Furardicarboxylic acid and 1,3-Propanediol: Synthesis, Thermal Behavior and Rheological Properties

A novel bio-based multi-block copolyester, poly(2,5-tetrahydrofurandimethanol 2,5-furandicarboxylate)-multi-poly(1,3-propylene 2,5-furandicarboxylate) (PTPF), was synthesized by the melt interfacial co-polycondensation of poly(2,5-tetrahydrofurandimethanol 2,5-furandicarboxylate) (PTF) and poly(1,3-propylene 2,5-furandicarboxylate) (PPF). Owing to the partially alternating and partially random copolymer structure, PTPF showed thermoplastic properties intermediate between those of PTF and PPF, which was different from those of the corresponding PTF/PPF random copolymer. The chemical structures and properties of these copolyesters were investigated by ¹H NMR, ¹³C NMR, FTIR, DSC, TGA and torque rheometer. Similar solubility parameters between PTF and PPF were obtained by theoretical calculations, indicating the good compatibility between these two copolyesters. The T_g of PTF (75.2°C) was higher than that of PPF (56.1°C), suggesting the stronger rigidity of THFDM compared with 1,3-PDO. In addition, a significant shear thinning phenomenon was observed in the rheological test. Due to the unique thermal and rheological properties, PTPF may potentially be an alternative in the manufacture of fiber and film.