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 (Tg of 145°C, Td5% 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). [Display omitted] •High-performance poly(thioctic acid)-based thermosets is fabricated•Dual-dynamic networks facilitate the reshaping, repairing, and mild degradation•Thermosets waste is upcycled to polyurethane foam Addressing the recyclability of existing sulfur-containing polymers and developing new sulfur-containing polymers with inherent recyclability for the future material economy are both in line with the United Nations Sustainable Development Goals. By introducing natural small molecules of thioctic acid (TA) with intrinsic reconfiguration, a polyTA-based autocatalytic dual-dynamic thermosets with good mechanical and thermal properties is obtained. Owing to the reversible nature of ester bonds and disulfide bonds, the crosslinked networks could be degraded mildly in basic aqueous solution, and their wastes can be subsequently upcycled into polyurethane foam. We innovatively utilize their wastes to selectively produce valuable chemicals and realize the life cycle of high-performance materials. The strategy of autocatalytic dual-dynamic thermosets in this work will inspire the development of engineering applications of polyTA. By incorporating natural small molecules of thioctic acid (TA) into crosslinked networks, a polyTA-based autocatalytic dual-dynamic thermoset was obtained. This thermoset exhibits remarkable mechanical and thermal properties and can b