Reconfigurable and Chemically Recyclable Thermosets via Cooperative Sulfhydryl–Disulfide Exchange in Sulfur-Rich Dynamic Networks

Achieving a balance between high performance and recyclability in thermoset polymers remains a formidable challenge, primarily due to the absence of efficient and controllable dynamic exchange strategies. Herein, we report a covalent adaptable network (CAN) based on an episulfide resin, featuring a dual dynamic pathway for network topology reconstruction by synergistic sulfhydryl–disulfide and disulfide–disulfide bond exchange. The ring-opening of episulfide monomers generates pendant sulfhydryl groups that actively participate in dynamic bond exchange, endowing the network with rapid stress relaxation ( E a = 33 kJ/mol) and excellent reconfigurability. The resulting sulfur-rich material demonstrates superior thermomechanical performance ( T g = 89 °C, tensile strength = 18.9 MPa), high shape fixity ( R f > 94%), robust solvent resistance, and rapid self-healing. Notably, the network undergoes over 99% degradation within 2 h under mild conditions, highlighting its closed-loop chemical recyclability. These findings demonstrate a dual-dynamic covalent design strategy for constructing recyclable, high-performance thermoset materials.