Modification of SiO₂ Nanoparticles by Bifunctional Silanes

SiO₂ nanoparticles modified with three bifunctional silanes—3-(trimethoxysilylpropyl) methacrylate, bis[3-(trimethoxysilyl)propyl]amine, and vinyltriethoxysilane—are obtained. Successful completion of the modification is confirmed by IR spectroscopy and scanning electron microscopy. In order to obtain coatings with increased hydrophobicity, modified SiO₂ nanoparticles are introduced into cycloaliphatic epoxy resin. To improve the physical and mechanical properties, the coating composition contains 30 wt % modified SiO₂ nanoparticles fillers are introduced: muscovite mica and titanium dioxide. It is shown that the most promising additive for obtaining hydrophobic coatings are SiO₂ nanoparticles modified by bis[3-(trimethoxysilyl)propyl]amine. When they are introduced in the epoxy-polymethylmethoxysilsesquioxane matrix in an amount of 40 wt %, the highest contact angle of wetting of 116° is observed.