Surface modification of silica powder by mild ball milling

Surface modification of silica particles without a catalyst or solvent was performed using mild ball milling. The effects of the amount of the modifier, hexatrimethoxysilane (HTMS), ball milling time, and the washing process were investigated. HTMS was physically and chemically adsorbed on the silica surface by ball milling; the adsorbed HTMS reacted with the silica particles on the surface during heat treatment. The adsorption amount of HTMS in silica particles increased with the increase in the milling time to 6 h. The modified silica particles were well dispersed in the cyclohexane because the silica was successfully modified by HTMS. In addition, the number of hydroxyl groups on the silica surface affected the adsorption ratio of HTMS; chemical adsorption could be increased using silica with a large number of hydroxyl groups. Therefore, this simple method, by which the amount of chemical adsorption can be easily modulated, is a valuable tool for the homogeneous modification of silica powder.