Modification of poly(ethylene 2,5-furandicarboxylate) with 1,4-cyclohexanedimethylene: Influence of composition on mechanical and barrier properties

Abstract

A series of poly(ethylene-co-1,4-cyclohexanedimethylene 2,5-furandicarboxylate)s (PECFs) with different compositions were synthesized from 2,5-Furandicarboxylic acid (FDCA), 1,4-cyclohexanedimethylene (CHDM) and ethylene glycol (EG). Their chemical structures, composition and sequence distribution were determined by FT-IR, 1H NMR and 13C NMR. The composition of the resulted polyesters could be controlled by the feed mole ratio of CHDM to dimethyl furan-2,5-dicarboxylate (DMFD). And for all the copolyesters, the degree of randomness (R) was close to 1, indicating their randomness. Their thermal and mechanical properties were investigated by Differential Scanning Calorimeter (DSC) and tensile testing, results showed that the crystallizability, tensile modulus and strength of PECFs were decreased with the increasing content of CHDM at first (0–59%), and with the introduction of more CHDM (76–100%) units, they were increased accordingly. However the elongation at break was changed contrarily. The barrier properties study demonstrated that although the O2 and CO2 permeability of PEF was increased by the introduction of CHDM, PECF-32 and PECF-76 still showed excellent barrier properties, which were better or comparable to those of PEN and PEI.