Study on Silica Aerogel Modified by Trimethylchlorosilane

The mechanical properties of SiO2 aerogel prepared under atmospheric pressure are poor, so it is difficult to prepare large pieces of materials for practical engineering. In this paper, trimethylchlorosilane (TMCS) was used as a surface modifier to transform hydrophilic substances with higher surface activity into hydrophobic groups, to improve the network strength of SiO2 aerogel. Super-hydrophobic SiO2 aerogel was prepared by the sol-gel method under atmospheric pressure. The effects of trimethylchlorosilane on the structure and properties of SiO2 aerogel were characterized by a specific surface area analyzer, Fourier transform infrared spectrometer, thermal conductivity meter, static contact angle meter, and scanning electron microscope. The results show that the SiO2 aerogel prepared when n (Si):n (TMCS) is 1 has the best performance. Its density is as low as 0.0759 g/cm3, the porosity is as high as 96.5%, the specific surface area is as high as 723.08 m2/g, and the contact angle is 163.8°. It has good hydrophobic properties.