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

ABSTRACT 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.