Fully bio-based poly(propylene succinate-co-propylene furandicarboxylate) copolyesters with proper mechanical, degradation and barrier properties for green packaging applications

Abstract

A series of aromatic-aliphatic poly(propylene succinate-co-furandicarboxylate) (PPSF) copolyesters, with compositions varied over the whole range from that of poly(propylene succinate) (PPS) to poly(propylene furandicarboxylate) (PPF), were synthesized by transesterification and melt polycondensation. 1H NMR study suggested the random segment distribution of PPSF. The copolymer showed slower crystallization rate than that of terephthalate based copolyesters, as indicated by DSC tests. PPSFs with low furandicarboxylate molar content (mPF) (from 10% to 50%) were soft and elastic due to their poor crystallization ability and low Tg. In contrast, they owned relatively high elastic modulus, tensile strength and excellent barrier properties with high mPF (from 60% to 90%). Annealing treatment could speed up the crystallization of PF units and increase the elastic modulus and tensile strength of PPSFs. The chemical composition of the copolymer strongly influenced its permeability to CO2 and O2, and PPSF owned better CO2, O2 and H2O barrier properties than commercial PBAT and PLA. Furthermore, enzymatic degradation study suggested that copolymers with mPF up to 60 mol% could be degraded and PPSF became easier to degrade with the increasing content of succinate units (mPS).