STRUCTURAL INVESTIGATION IN MONOLITHIC SILICA AEROGELS AND THERMAL-PROPERTIES

The influence, of the number of water molecules (n) used to synthesiz e polyethoxydisiloxane (PEDS-Px) silica precursors, on the internal st ructure of aerogels made with those precursors in ethylacetoacetate (e tac) under HF conditions and dried under CO2 supercritical conditions was studied.Gas adsorption, water thermoporometry and mercury porosime try were used to characterize specific area and pore size distribution . The results were used to interpret the evolution of the apparent the rmal conductivity of those aerogels with n. Optical transmission was also measured to estimate optical quality of the aerogels prepared. (C ) 1998 Elsevier Science B.V. All rights reserved.