Preparation and Performance Characterization of SiO_2 Aerogel by Multi-Hydrophobic Modification

The hydrophobic SiO2 with low density aerogel was prepared using tetraethoxysilane(TEOS) and methyltriethoxysilane(MTOS) as co-polymer Si source,N,N-dimethylformamide(DMF) as chemical drying controlling additive,trimethylchlorosilane(TMCS) and γ-methylpropenoyloxypropyl trimethoxylsilane(KH-570) as situ hydrophobic modifier by sol-gel method and drying under ambient pressure.Its structure and performance were characterized by using scanning electron microscopy(SEM),N2-adsorption apparatus,Fourier infrared(FT-IR),X-ray diffraction and thermal analysis instruments.The results show that the specific surface area of the prepared SiO2 aerogel is up to 870.99 m2/g,the pore volume is 1.74 cm3/g,the density is 0.244 g/cm3,the porosity is 88.9%,the hydrophobic performance can be maintained even at 430 ℃,the pore size distribution is focused on 11 nm.The SiO2 aerogel is typical mesopore nano material.