Remarkable Strain Hardening, Elasticity, and Gas Barrier of Biobased Poly(1,5-pentylene itaconate- <i>co</i> -furanoate- <i>co</i> -ε-caprolactone) Elastomers

The widespread utilization of elastomers causes severe environmental and health concerns, prompting the research of biobased high-performance elastomers for a sustainable elastomer industry. This work attempts to develop biobased elastomers with comparable properties with high-performance petroleum-based synthetic rubbers and natural rubber. A series of poly(1,5-pentylene itaconate-co-furanoate-co-ε-caprolactone) (PPeIFCL) polyesters were synthesized by using transesterification and melt polycondensation methods utilizing biomass-derived substituents. PPeIFCL polyesters were characterized in terms of chemical structure and thermal, mechanical, and gas barrier properties. PPeIFCL polyester macromolecule chains with an inherent angle of 129.4° between the carboxylates on furan moieties, combining the asymmetric poly(ε-caprolactone) diol oligomer and “odd–even” effect of the 1,5-pentanediol structure, provided adequate chain entanglements and strengthened their tensile strength and elasticity as validated by the mechanical tests and low-field NMR. Furthermore, PPeIFCLs exhibited impressive gas barrier properties compared to petrobased butyl rubber.