Biobased 1,5-pentanediol derived aliphatic-aromatic copolyesters: Synthesis and thermo-mechanical properties of poly(pentylene succinate-co-terephthalate)s and poly(pentylene adipate-co-terephthalate)s

1,5-Pentanediol (PeDO) is a biobased but less studied diol monomer for polyester synthesis. As one of a series of studies on PeDO-derived polyesters, two aliphatic-aromatic copolyesters, poly(pentylene succinate-co-terephthalate) (PPeST) and poly(pentylene adipate-co-terephthalate) (PPeAT), were synthesized through melt copolycondensation of biobased PeDO, SA (or AA) and TPA. The chemical structure was characterized by H-1 NMR, and the thermo-mechanical properties were assessed by DSC, WAXD, TGA and tensile test. The H-1 NMR results demonstrated random structure and controllable copolymer composition. PPeATs showed two-stage thermal decomposition as the PeA units were clearly less stable than the PeT units at high temperature. In comparison, PPeSTs exhibited better thermal stability which was improved with increasing PeT unit content. Due to the difference in thermal stability, high intrinsic viscosity (0.78-1.4 dL/g) was facilely reached in synthesizing PPeSTs with melt copolycondensation, but medium intrinsic viscosity (0.58-0.66 dL/g) for PPeATs. Both kinds of copolyesters showed isodi-morphism behavior and composition-dependent weak crystallizability. The PeT-rich copolyesters like PPeST(85) and PPeAT(85) showed reasonably good tensile properties because of higher crystallizability and stronger chain interaction. (C) 2019 Elsevier Ltd. All rights reserved.