Thermally activated and fire-resistant thiol-Michael dynamic crosslinking networks for wildfire prevention

Dynamic covalent polymer networks that undergo bond exchange under external thermal stimulation exhibit unprecedented superior properties. However, under elevated temperatures, their topological structures rapidly dissociate, leading to a significant reduction in crosslinking density and limiting their application range. Herein, a thermally activated thiol Michael dynamic crosslinking strategy is proposed. This strategy enables the incorporation of vinyl groups within thiol Michael linkages at low temperatures, during which the dynamic exchange of thiol Michael linkages occurs. When exposed to external high heat, the vinyl groups dissociate from the thiol Michael linkages, and the self-polymerization of these is activated, altering the topological structure and assembling into a thermal crosslinking network, so that the material can still exert excellent performance characteristics. Interestingly, based on this strategy, a sunlight-polymerizable material with excellent self-healing, tolerance, and fireproof properties is designed. This material is particularly well-suited for fireproof protection of high-voltage direct-current systems deployed in wildland-urban interface areas. This conceptually novel thermally activated strategy surpasses the original upper temperature limits of dynamic crosslinking networks, providing innovative design approaches for dynamic network design and enabling high-temperature application scenarios.