High Efficiency Self-Healing and UV Resistance of Epoxy Composites With Dual-Compartment Microcapsules

Microcapsule-based self-healing systems, capable of remediating epoxy resin fatigue microcracks, present promising prospects for prolonging their service life. However, there is a pressing need to improve the mechanical properties, especially toughness, of the composite resin. Herein, a dual-compartment microcapsule was proposed to ingeniously integrate into the epoxy resin matrix, which could endow the composites with improved toughness and the remarkable capability of self-repair against intrinsic injuries. Preparation methods included the soap-free emulsion polymerization for PSA nanoparticles loaded with the healing agent, alongside the development of PDA nanoparticles encapsulating a catalyst through Pickering emulsion polymerization. Subsequently, a composite microcapsule was assembled via a coupling reaction between PSA and PDA nanoparticles. Self-healing performance indicated that the incorporation of 2 wt% microcapsules could significantly restore the tensile strength of epoxy resin to 68.37%. Remarkably, the long-term anti-corrosion of the epoxy coating with microcapsules was typically improved using electrochemical impedance spectroscopy measurements. The low-frequency impedance logarithm value of the composite coating remained stable at approximately 7.1, whereas the pure epoxy coating has dropped to 4.8. Furthermore, epoxy/microcapsule composite resin exhibited UV aging resistance and commendable storage stability at ambient conditions. This strategy provides epoxy resin with improved toughness, corrosion resistance, anti-UV irradiation, and self-healing performance.