Silica aerogels were synthesized via solvent exchange/surface modification of wet gels from waterglass using IPA/TMCS/n-Hexane solution. The densities, porosities, and specific surface areas of the aerogel were in the range of 0.128-0.153 g/cm(3), 93-95%, and 598-795 m(2)/g, respectively. Aerogel-PVB composites were manufactured by hot pressing. Aerogels were crushed and mixed with PVB. Three mixing methods were performed. The aerogel-PVB composites had densities of 0.19-1.09 g/cm(3), and thermal conductivities of 0.03-0.12 W/(m . K). Density and thermal conductivity can be controlled by aerogel volume fraction and the mixing method. The modulus of rupture of aerogel-PVB composites was in the range of 0.15-46.5 MPa. (C) 2003 Kluwer Academic Publishers.