Multiple Structure–Property Relationship Regulation for Self-Healing Polyurethane Systems With Dynamic Disulfide Bonds

With the expanding use of polyurethane materials under complex service conditions, mechanical damage and the associated degradation in performance have become increasingly critical issues. Introducing intrinsic self-healing can extend service life and reduce material consumption, yet simultaneously maintaining high mechanical performance and efficient healing remains challenging. In this work, a series of intrinsically self-healing polyurethanes were constructed by incorporating dynamic disulfide bonds into the polymer network, and the effects of multiple structural parameters on the comprehensive performance were systematically investigated. By regulating the soft segment type, soft segment molecular weight, chain extender structure, and chain extender content, the mechanical properties, self-healing behavior, and thermal properties were evaluated. The results indicate that different structural parameters cooperatively govern material performance by modulating network structure, chain mobility, and hydrogen-bonding interactions. In particular, the soft segment type and molecular weight significantly influence self-healing behavior and thermal characteristics through their effects on chain mobility and phase structure, whereas the chain extender structure and chain extender content primarily determine network rigidity and mechanical performance. From the perspective of multiparameter structural regulation, this study elucidates the structure–property relationships of dynamic disulfide bond–based polyurethane systems, providing research guidance for the rational design and performance optimization of self-healing polyurethanes.