High Strength and Mildly Closed-loop Recoverable Epoxy Vitrimer with Dual Reversible Dynamic Bonds

Currently, the primary limitation hindering the sustainable application of epoxy (EP) vitrimers lies in the inherent trade-off among high mechanical performance, efficient recovery capability and mild recycling conditions. To address this challenge, we designed an EP polymer that leverages the high rigidity of imine bonds and the rapid bond exchange of boronic ester linkages, simultaneously achieving high mechanical performance, efficient recovery capability, and mild-condition recyclability. The resulting material exhibits a high mechanical strength of 78.6 MPa, excellent recovery efficiency (>90% after two cycles of crushing and then hot-pressing at 130°C), and mild solvent-assisted closed-loop recycling. Furthermore, carbon fiber-reinforced polymers (CFRPs) fabricated with this EP vitrimer demonstrated complete degradation in (solvent) within 30 min at 50°C. The reclaimed carbon fibers (CF) retained pristine surface morphology and preserved 96% of their original mechanical properties, enabling highly efficient and non-destructive recovery. These findings highlight the potential of this EP vitrimer system, offering a promising strategy for the sustainable development of polymer materials.