Complete Degradation of a High-Performance Epoxy Thermoset Enabled by γ-ray-Sensitive Motifs Based on the Cascaded Synergetic Strategy

γ-Radiation derived from clean energy has emerged as a promising technology for disposal of waste plastics. However, due to radical-mediated uncontrolled recombination, a foremost challenge remains in radiation-triggered complete degradation for thermoset plastics. Herein, the radiation-sensitive epoxy thermoset (EP-DESN) containing phenyl imine-conjugated N-N bonds (PINN bonds) and S-S bonds was designed to initiate rapid degradation at a dose of 10 kGy. The phenyl imine-conjugated linkages can stabilize the radiation-induced broken N-N bonds, overcoming radical-mediated uncontrolled recombination and cross-linking. Moreover, the phenyl-iminyl-conjugated radicals generated by PINN bond scission can cleave the active S-S bonds to promote subsequent spontaneous degradation for maximum degradation efficiency. Meanwhile, EP-DESN exhibited superior thermal robustness and chemical resistance comparable to some conventional high-performance epoxy thermosets. Using EP-DESN as a binder, we prepared recyclable carbon fiber-reinforced composites, and nondestructive recycling of value-added carbon fiber (CF) is achieved, thus facilitating the concept of a circular CF economy.