Abstract
Conditions that afford effective hydrophobicity to a dry process were examined by preliminarily treating coupling agents, VTES and VTMS, under various conditions and the correlation existing among oligomer formation, water consuming rate and hydrophobicity M value were considered. The main findings obtained are as follows: 1) Hydrophobicity M values increase with the preliminary treatment time of the coupling agent, and the time required for the stand up of M value was shortened by increasing initial water concentration, decreasing the initial solvent alcohol concentration, lowering of the pH value of aqueous phase and elevation of the temperature. 2) The behavior of the M value of TiO2 was greatly affected by oligomer formation in the solution of preliminary treatment. and 3) The existence of an intimate relationship between the half-life of VTES or VTMS monomer in the solution of preliminary treatment and hydrophobicity M value of TiO2 determined at the same preliminary treatment duration was found, thus the half-life was considered an important parameter for establishing conditions that afford effective hydrophobicity to TiO2.
