Ring-Opening Copolymerization Synthesis of Tailored Biobased Block Polyesters and Their Application as Biocompatible Additives within Tire Rubber Formulations

Abstract

Aliphatic polyesters (APEs) are premier candidates for sustainable materials due to their biocompatibility and hydrolytic degradability. However, expanding their structural and thermal diversity requires moving beyond traditional petroleum-based monomers toward renewable, biosourced alternatives like carbohydrates, vegetable oils, and terpenes. In this study, the ring-opening copolymerization (ROCOP) of biobased epoxides derived from fatty acids and terpenoids with phthalic anhydride (PA) is reported, using Fe(III) and Cr(III) catalysts with [OSSO]-type ligands. Materials with tunable thermal and mechanical characteristics, depending on block composition and feeding ratios, were produced by subsequent diblock (AB) and triblock (ABA/BAB) copolymerizations using cyclohexene oxide (CHO) and vinyl cyclohexene oxide (vCHO). We adopted a comprehensive approach that takes into account the full material lifecycle in order to assess the overall sustainability of these innovative polyesters. This strategy started with the selection of biobased monomers and continued with hydrolytic degradability and preliminary cytotoxicity testing to assess their environmental safety. Finally, a key application explored is the replacement of nonrecyclable, harmful additives in tire formulations by utilizing thermoplastic polyester elastomers, creating materials with mechanical performance but enabling easier recycling and reprocessing compared to traditional tire additives.