The Synthesis and Characteristic of Silica Aerogels by Ambient Pressure Drying Process

Using tetraethoxysilane(TEOS)as the silica source,silica aerogels were synthesized via sol-gel and ambient drying process. In order to enhance the wet gel,measures such as prolonging aging time; changing solvent and trimethylchlorosilane(TMCS)/hexane modification were adopted. The synthesized silica aerogel was a light,porous and crack-free solid. The influences of catalyst mass,H2O and ethanol on gel time were also studied. The microstructure,morphology and properties of the aerogels were characterized by FTIR,XRD and SEM. The density,the specific surface area,porosity and particle diameter of hydrophobic SiO2 aerogels range from 77 to 200 kg·m-3,500 to 750 m2g-1 and 88% to 93% and 50 to 200 nm,respectively.