Effects of mica modification with silane on the interface and corrosion resistance of ultraviolet curable epoxy acrylate/mica composite coatings

Ultraviolet curable composite coatings are an eco-friendly option with the absence of volatile organic compound emissions. Achieving a better interface between epoxy acrylate (EA) and mica is essential for the enhanced mechanical and barrier properties of composite coatings. This paper presents a strategy for modifying mica through in situ grafting with various silane coupling agents (KH550, KH560, and KH570) and preparing composite coatings of EA/mica using a blending method. The results indicate that the silane-modified mica exhibited enhanced compatibility with EA coatings. The mechanical properties, thermal stability, and corrosion resistance of epoxy acrylate/silane-modified mica coatings were improved compared to epoxy acrylate/unmodified mica composite coatings. KH570 was found to be the most effective modifier for enhancing these properties of the coatings. Relative to EA/unmodified mica composite coating, the impact resistance of EA/KH570-modified mica composite coatings doubled, with increases in T₅ and T₁₀ by 49.7°C and 9.7°C, respectively. During the 9 day monitoring period using electrochemical impedance spectroscopy, the total impedance modulus |Z|_f=0.01 Hz of EA/KH570-modified mica composite coatings was discovered to be 6–9 times higher than that of unmodified mica coatings, with the R_t value higher by two orders of magnitude.