PROPERTIES OF LOW-DENSITY BULK SILICA-GEL LYOSIL

Bulk silica gels prepared by hydrolysis, gelation and curing of tetram ethoxy silane were further characterized. The pore size distribution i s narrow in the range of 13.1 nm and the BET surface area is 622 m2/g. Visible light transmittance for bulk lyosil of 0.5 cm thick plate is 80% with UV cut off at 300 nm of a lyosil having bulk density of 0.40 g/cm3. Thermal conductivity of a dried monolithic lyosil is 0.065 W/m K and remained unchanged after firing in air at 600-degrees-C. Electro n micrographs show that lyosils have uniform distribution of several n anometer sized silica particles linked together.