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 degrees is observed.