Biobased copolyesters: Synthesis, structure, thermal and mechanical properties of poly(ethylene 2,5-furandicarboxylate-co-ethylene 1,4-cyclohexanedicarboxylate)

A series of bio-based copolyesters, poly(ethylene 2,5-furandicarboxylate-co-ethylene 1,4-cyclohexanedicarboxylate)s (PEFCs) were synthesized from ethylene glycol (EG), 2,5-furandicarboxylic acid (FDCA) and 1,4-cyclohexanedicarboxylic acid (CHDA) through a two-step melt polycondensation procedure. The chemical structure, compositions and sequence distributions were determined by 1H NMR. The molecular weight, thermal properties, thermal stabilities, crystal structure and mechanical properties were investigated by GPC, DSC, TGA, WAXD, and tensile testing, respectively. All PEFCs showed the characteristic of random copolymer, and their composition could be controlled by the feed molar ratio of FDCA to CHDA. DSC results showed that PEFCs were amorphous, while increasing the content of the CHDA unit, the glass transition temperatures (Tg) of PEFCs decreased. Moreover, the thermal stabilities of all PEFCs remained unchanged. The tensile testing demonstrated that PEFC-30 was a toughened plastic with tensile modulus 801 MPa and elongation 667%.