Hydrophobic modification of silica aerogels with methyltrimethoxysilane

The hydrophobic silica aerogels were prepared by using tetraethylorthosilicate as precursor and methyltrimethoxysilane as modification agent by a co-precursor method with supercritical drying.Contact angle measurement,pore size distribution,thermo-gravimetric and differential scanning calorimetry(TG-DSC),and Fourier transform infrared spectroscopy(FT-IR) were used to characterize the properties and the structure of hydrophobic silica aerogels.Results showed that the silica aerogels were hydrophobic,and the contact angle,the specific surface area and the pore volume were 160°,674.47 m2/g and 4.13 cm3/g.The temperature of the thermal stability for hydrophobic silica aerogels was 244.5 ℃ in air.