Abstract
Since the oligomer state of the coupling agent plays an important role in the hydrophobicity of inorganic oxides, various factors affecting the time variation in the average polymerization degree, determined through GPC analysis of preliminary treatment solution and water content determined by the Carl-Fisher method, were studied for the VTES or VTMS-Alcohol-H2O system. The main findings obtained are as follows: (1) The existence of a close relationship between the decreasing rate of the coupling agent monomer and time variation of the height of GPC elution peaks for polymer was qualitatively detected. (2) Time variation of polymerization degree determined from water content of the preliminary treatment solution is intimately related to the progressive rate of oligomer formation reaction. (3) Decreasing rates of water concentration in the preliminary treatment solution were increased by the increase in the initial water concentration, decrease in the alcohol concentration as well as the pH value of the aqueous solution and the elevation of temperature and lowered by the sequence MeOH, EtOH and i-PrOH.
