Degradable and self-repairable polyurethanes with superior mechanical properties and remarkable healing capability

Self–healing polyurethanes relying on a single dynamic covalent bond often face trade-offs between mechanical performance and healing efficiency. In this work, we developed an innovative self-healing elastomer by strategically incorporating imine bonds into a Diels–Alder (DA) adduct-based polyurethane. The resulting material exhibited exceptional mechanical properties, achieving a tensile strength of 26.9 MPa and an elongation at break of 513.3%. Remarkably, PUDI retained 90.0% of its tensile strength and recovered 71.9% of dissipated energy after 10 fatigue cycles at room temperature. This dual dynamic bonds system enabled outstanding self–healing performance, complete healing at 120 °C—significantly surpassing conventional DA–based polyurethanes. Moreover, the material maintained a high repair capability at reduced temperatures, demonstrating consistent healing efficiencies of 94.3%, 90.9%, and 79.2% over three damage–repair cycles. Notably, the incorporation of dynamic imine bonds significantly enhanced degradation performance, primarily due to improved chain mobility and dynamic network rearrangement. This work overcomes fundamental limitations of traditional self-healing polyurethanes, offering a promising platform for advanced applications in flexible electronics, protective coatings, and biomedical devices.