SILICA AEROGELS BY SUPERCRITICAL EXTRACTION

Aerogels of different densities were prepared from silica gels by supe rcritical drying in a high temperature and high pressure plant. Gels w ere synthesised front tetramethoxysilane (TMOS) using acetone or metha nol as solvents. For the acetone gels, several volume ratios of precur sor and solvent were used. Properties of the obtained aerogels were an alysed and their pore structure was studied by gas/vapour adsorption a nd scanning electron microscopy (SEM). Changing the volume ratio of pr ecursor and solvent reveals itself as an easy way to modify the densit y, porosity and mechanical strength of the acetone aerogels. (C) 1998 Elsevier Science Limited. All rights reserved.