Preparation, Mechanical Properties and Thermal Properties of Elastic Aerogels

Transparent and monolithic aerogels were prepared via acid-base two step Sol-Gel process with Me- thyltrimethoxysilane (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 char- acterize the morphology, pore structure, mechanical properties and thermal properties of the aerogels. The ob- tained 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/(mK) 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.