The invention relates to a process for the preparation of monolithic
xerogels and aerogels of silica/latex hybrids under subcritical
conditions. In the two-stage synthesis of these alcogels in the presence
of an acid-base catalyst, the hydrolysis and polycondensation of a
silicon alkoxide are carried out in an organic medium containing excess
water. A latex consisting of polybutyl methacrylate and polybutyl
acrylate, modified with alkoxysilane groups, is first synthesized and
then incorporated in the mixture either in the first stage in order to
effect its co-hydrolysis with the silicon alkoxide, or in the second
stage to effect its co-condensation with the previously hydrolysed
colloidal silica. The resulting alcogels are aged, washed, and dried
under subcritical conditions. This process gives hybrid products
containing 0.1-50 wt-% of latex and having a density of 300-1300 kg/m3, a
porosity of 40-85%, a specific surface area of 400-900 m2/g and a mean
pore diameter of 2-12 nm. The products are resistant to atmospheric
humidity and moisture, have better mechanical properties than the
corresponding inorganic products, and can be used as thermal, acoustic
and electrical insulators.