Abstract: Transparent and monolithic aerogels were prepared via acid-base two step Sol-Gel process with Methyltrimethoxysilane (MTMS), water, acetic acid and ammonia as precursor, solvent, acid and base accelerators, respectively, followed by drying under a supercritical condition using alcohol as drying medium. Scan electron microscope, N2 adsorption analyzer, dynamic mechanical analyzer, hotdisk thermal analyzer were used to characterize the morphology, pore structure, mechanical properties and thermal properties of the aerogels. The obtained aerogels showed good elastic properties. They could shrink up to 60% in linear scale and rebound to 78% of their original size when unloaded, and finally spring back to 94% of their original size after heat treatment at about 100℃. The aerogels also had good thermal insulation properties. The thermal conductivity was about  0.028 W/(m?K) at room temperature. The contact angle was up to 154°, showing good hydrophobicity. The heat-resistance temperature of the aerogels was about 440℃, above which would result in oxidation of methyl groups in the aerogels. The aerogels have good mechanical and thermal insulation properties, showing prospect in the application of thermal insulation.

Key words: aerogel, methyltrimethoxysilane, elastic property, low thermal conductivity