Dynamic aminal-based epoxy resins with high mechanical robustness, thermal stability, and on-demand degradability

In this work, multi-arm aminal curing agents were designed to construct dynamic epoxy networks with one exchangeable aminal linkage per crosslinking point. Benefiting from the rigid hexahydropyrimidine rings and norbornene-derived structures, the resulting thermosets exhibit high mechanical performance, elevated glass transition temperatures, and good thermal stability, while maintaining structural integrity under long-term mechanical loading, as evidenced by suppressed stress relaxation and reduced creep deformation. Despite their robustness in service conditions, the networks undergo controllable amine-triggered degradation under amine-rich conditions, featuring slow depolymerization at room temperature and rapid degradation at 60 °C. Carbon fiber composites fabricated from the optimized resin show good processability and mechanical performance, and enable damage-free fiber recovery under mild conditions. Moreover, the resins demonstrate potential as recyclable electronic encapsulation materials, combining high volume resistivity, thermal reliability, and on-demand removability for intact component retrieval.