The regulation of topological structure of covalent adaptable networks (CANs) remains a challenge for epoxy CANs. Here, we report a strategy to develop strong and tough epoxy supramolecular thermosets with rapid reprocessability and room-temperature closed-loop recyclability. These thermosets were constructed from vanillin-based hyperbranched epoxy resin (VanEHBP) through the introduction of intermolecular hydrogen bonds and dual dynamic covalent bonds, as well as the formation of intramolecular and intermolecular cavities. The supramolecular structures confer remarkable energy dissipation capability of thermosets, leading to high toughness and strength. Due to the dynamic imine exchange and reversible noncovalent crosslinks, the thermosets can be rapidly and effectively reprocessed at 120 °C within 30 s. Importantly, the thermosets can be efficiently depolymerized at room temperature, and the recovered materials retain the structural integrity and mechanical properties of the original samples. This strategy may be employed to design tough, closed-loop recyclable epoxy thermosets for practical applications.

The development of epoxy vitrimers with excellent overall properties and recyclability has been a great challenge. In this work, an itaconic acid-based hyperbranched polymer (IAHBP) was synthesized and incorporated as a curing agent for diglycidyl ether of bisphenol-A (DGEBA) to prepare epoxy vitrimers. The tensile strength, flexural strength and impact strength of DGEBA/IAHBP were 91.0 MPa, 121.8 MPa and 18.4 kJ m⁻² respectively. The hyperbranched topological structure of IAHBP promoted dynamic transesterification and DGEBA/IAHBP exhibited outstanding malleability, shape reconfiguration and reprocessibility. DGEBA/IAHBP showed high shape fixity (R_f ∼ 97%) and recovery ratio (R_r ∼ 99%) over ten shape memory cycles, which involved grasping and loosening motions and the recovery of complex objects such as flower-shaped and 3D butterfly-shaped objects. Due to the increased free volume and crosslinking density, DGEBA/IAHBP demonstrated excellent solvent resistance. DGEBA/IAHBP can be efficiently degraded using sodium hydroxide aqueous solution, with the degraded epoxy reused to cure DGEBA to produce new epoxy vitrimers. The recycled epoxy vitrimers presented similar mechanical properties and T_g to the original samples. This work demonstrated a green and convenient strategy for the production of epoxy vitrimers with excellent mechanical performance and environment friendly reprocessibility.