Superior pseudo-vitrimer: A high-performance bio-based polyurethane with self-healing and chemical recyclability via Diels-Alder chemistry

Abstract

The increasing demand for high-performance sustainable polymers has highlighted both the potential and the limitations of conventional polyurethane (PU). Thermoplastic PUs offer recyclability but suffer from insufficient mechanical robustness, whereas thermosetting PUs provide strength at the cost of irreversibility and environmental burden. Herein, we report a bio-based pseudo-vitrimer elastomer featuring dynamic covalent adaptable networks (CANs) formed via Diels-Alder chemistry between 2,5-bis(hydroxymethyl)furan and a bismaleimide. The resulting pseudo-vitrimer network exhibits superior mechanical performance, with a tensile strength of 73.5 MPa and a 2%-strain modulus of 22.8 MPa, corresponding to a 1.4-fold increase in tensile strength and a 2.7-fold increase in modulus compared to conventional thermoplastic polyurethanes, while maintaining excellent elastic recovery. The pseudo-vitrimer also demonstrates shape memory behavior (92% retention and 100% recovery), self-healing ability, and strong interfacial adhesion. Furthermore, the elastomer can be reprocessed and chemically recycled in a closed-loop manner, offering a promising route toward low-carbon and circular polyurethanes. These results underscore the versatility of bio-based Diels-Alder networks for designing nextgeneration recyclable polyurethane elastomers.