High-performance poly(thioctic acid)-based thermosets featuring upcycling ability for in situ foaming enabled by dual-dynamic networks

Polymers constructed from natural thioctic acid (TA) provide a solution for the development of sustainable materials. However, their inherent weak networks make them difficult to use in engineering materials featuring high durability and mechanical robustness. In this work, the autocatalytic dual-dynamic covalent adaptable networks (CANs) are devised by curing diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate (DGEDC) with TA and bis(p-aminocyclohexyl)methane (PACM). The resulting DGEDC/TA/PACM thermosets exhibit good mechanical and thermal properties (T_g of 145°C, T_d5% of 289°C, tensile strength of 70 MPa, Young’s modulus of 2.25 GPa), higher than previous poly(thioctic acid)-based materials. Due to topological network rearrangements induced by the exchange of disulfide bonds and tertiary amine-catalyzed transesterification reactions, they can be easily reshaped and repaired. Furthermore, they can be degraded mildly and upcycled into polyurethane foam by in situ foaming. This strategy of autocatalytic dual-dynamic CANs will inspire the development of practical applications of poly(thioctic acid).