Achieving excellent wear resistance and erosion resistance of carbon fiber/epoxy composite coatings via two-step chemical grafting for interfacial strengthening

Carbon fiber is chemically inert and has poor compatibility with the polymer resin, which severely limits the protective ability of carbon fiber reinforced polymer coatings. In this work, we successfully fabricated two carbon fiber reinforced polymer coatings through a two-step chemical grafting strategy, utilizing hyperbranched polyimidazole and aminopropyltriethoxysilane for interfacial modification. The different grafting order led to disparities in the wear resistance and erosion resistance between the two-step modified carbon fiber reinforced polymer coatings. Specifically, the first aminopropyltriethoxysilane and then hyperbranched polyimidazole modified carbon fiber reinforced polymer coating exhibited the most prominent performance in terms of wear resistance, with a 38.7 % reduction in the wear rate relative to oxidized carbon fiber reinforced polymer coating. On the other hand, the first hyperbranched polyimidazole and then aminopropyltriethoxysilane modified carbon fiber reinforced polymer demonstrated the optimal performance in terms of erosion resistance, with a 29.53 % and 33.96 % decrease in mass loss and volume loss, respectively, in comparison to oxidized carbon fiber reinforced polymer coating. Ultimately, the reinforcing mechanisms of wear resistance and erosion resistance for carbon fiber reinforced polymer coatings were deeply investigated, which would provide a crucial reference for the development of protective coatings applied in marine splash zones.