Process of Modified Industrial Silica Sol by Methyltrimethoxysilane and Its Mechanism

The modified silica sol was synthesized under acid catalyst and water bath conditions by sol-gel,using industrial silica sol and organic siloxane.Through studying on the influence factors of the modification,such as pH value,water-bath temperature and water bath time,methyltrimethoxysilane(MTMS) are chosen to modify the industrial silica sol.The optimal technical processes were obtained: MMTMS:MSiO2=2∶1~4∶1,pH value 3.5~5.5,bath temperature 50~70℃,bath time 40~120min.The structure of modified silica sol was also characterized by infrared spectrometry and the modified mechanism was discussed.The results show that the cross-linked reaction occurs between the surface of silica sol particles and hydrolysis products of MTMS,and the Si-O-Si network structure of the silica sol is coated,and interlink model of SiO2 particles with polymers of MTMS was obtained.