Performance-Tunable, Self-Healing, and Degradable Epoxy Insulation Material Based on Imine and Hindered Urea Dual-Dynamic Covalent Bonds

Traditional epoxy insulation materials are prone to irreparable damage during long-term operation, severely limiting the reliability and lifespan of electrical equipment. Their difficult degradability and recyclability pose significant environmental pressures. This study proposes a strategy based on a “rigid–flexible integrated” molecular design. By introducing hindered urea bonds and imine bonds, we successfully construct a dual-dynamic covalent bond epoxy resin network (H X V Y -EP) with adjustable proportions, which not only addresses the self-repair and degradation issues of traditional epoxy resins but also compensates for the defect of network imbalance caused by dynamic bonds. Precise control of material properties can be achieved by adjusting the proportion of dynamic bonds. For example, H 20 V 20 -EP exhibits excellent thermodynamic performance with tensile strength up to 95.2 MPa and the initial decomposition temperature above 250 °C. H 25 V 25 -EP shows a power frequency dielectric loss as low as 0.00599 and breakdown strength up to 40.36 kV/mm, which can be used in the area of high-end electrical equipment with low loss and high voltage resistance. Importantly, the material can achieve self-repair of mechanical damage within 10 min at 110 °C. Moreover, the material can be efficiently degraded at room temperature using various solvents, providing a feasible, environmentally friendly recycling pathway for epoxy. This work has achieved the coordinated optimization of the dynamicity, stability, and functionality of epoxy resin, and has broad application prospects in the fields of power equipment, aerospace, and sustainable electronic packaging.