Self-healing epoxy resin film enabled by the synergetic effect of coumarin and MXene

Flexible films, typically made from thermoplastic resins, are widely used but require improved thermodynamic properties. In contrast, epoxy resins have excellent thermodynamic properties but are difficult to form into films due to their poor flexibility. Herein, we propose an innovative strategy to synthesize a coumarin epoxy resin and enhance its self-healing properties by utilizing the photothermal conversion effect of MXene. By incorporating 4.0 wt% 6,7-dihydroxycoumarin into the epoxy structure, the resin film acquired photoinduced self-healing properties. The film exhibited a tensile strength of 3.8 MPa and a self-healing efficiency of 77.8%. Furthermore, the composite film, with the addition of 0.5 wt% MXene, exhibited improved photoinduced self-healing properties and mechanical properties. Its self-healing efficiency reached as high as 99.5%, and the tensile strength was increased to 16.4 MPa. At the same time, the thermal decomposition temperature of the composite film was 313.23 °C, and the T_g was 91.14 °C, which effectively retained the original excellent thermal properties of the epoxy resin. This study lays a foundation for the development of high-performance photostimulated self-healing epoxy resin materials.