A transesterification-based epoxy vitrimer synthesis enabled high crack self-healing efficiency to fibrous composites

Adipic acid was grafted onto a general epoxy resin and then crosslinked with a primary amine to synthesize a novel remenable epoxy vitrimer (EPV). Also, carbon nanotubes were added into EPV to obtain reinforced EPVC. Results reveal that EPV and EPVC show good self-healing efficiencies to their respective cracks, i.e. 74-77 % to fracture toughness and 62-67 % to tensile strength. But EPVC shows higher toughness and strength, respectively increased by 80 % and 3.2 % when compared with EPV. Also, the obtained fibrous composites are resistant to low temperature and the increased crack density is only 0.02 % after soaking in liquid nitrogen for 20 days, which can be completely healed by thermal activation. Moreover, EPV and EPVC-based laminates show a self-healing efficiency greater than 100 % to interlaminar toughness and strength after two loading-healing cycles. The EPVC laminate also has higher initial mechanical properties. Thus, the synthesized EPV/EPVC is potential in preparing self-healing structural composites.

Automated summary

This research reports the synthesis of a novel remenable epoxy vitrimer (EPV) by grafting adipic acid onto a general epoxy resin and crosslinking it with a primary amine. Results show that EPV and EPVC exhibit good self-healing efficiencies to their respective cracks. Additionally, EPVC possesses higher toughness and strength, as well as excellent low-temperature resistance.