Soft‐Segment‐Tuned Dynamic Polyurethanes With Low Compression Set and Recyclability

ABSTRACT

High‐performance polyurethane (PU) elastomers fundamentally suffer from a trade‐off between structural resilience and recyclability. Herein, we propose a strategy to reconcile this dichotomy by developing Diels‐Alder (DA) dynamic covalently cross‐linked PU elastomers (DAPU‐EEs) with precisely tailored polyether‐to‐polyester soft segment ratios. Systematically modulating this composition elucidates the structure‐property relationship, enabling the programmable optimization of mechanical robustness, thermal stability, and dynamic responsiveness. Empowered by the thermoreversible DA network, the optimized elastomer (DAPU‐EE2) exhibits efficient recyclability, retaining pristine mechanical properties after multiple hot‐pressing cycles. Crucially, DAPU‐EE2 demonstrates a remarkably low compression set of 15%, representing a 40% improvement over typical commercial TPU sealing materials. Furthermore, it exhibits superior solvent resistance and highly efficient processability with significantly reduced complex viscosities. Ultimately, this work provides a practical material design strategy that balances demanding mechanical performance with sustainable reprocessing, demonstrating promising potential for advanced sealing applications.