Abstract:
Process for the production of monoliths by means of the sol-gel process, comprising the following steps:
a. hydrolysis of an alkoxide in aqueous solution to form a hydrolysate and optionally evaporation to optimum concentration of the same, b. addition of an oxide prepared by the pyrogenic route, c. mixing of the hydrolysate of the alkoxide with the oxide prepared by the pyrogenic route to form a colloidal sol, d. optional removal of coarse contents from the colloidal sol, e. gelling of the colloidal sol in a mould, f. optional replacement of the water contained in the resulting aerogel by an organic solvent, g. drying of the aerogel, h. heat treatment of the dried aerogel, the coarse content being removed from the colloidal sol.
Abstract:
The present invention is concerned with a method for the preparation of aerogels that includes a phase of exchange with the liquid present in the aquagel by the liquid xenon and the subsequent extraction thereof.
Abstract:
It is described a process based on sol-gel chemistry suitable to the production of nanocomposite materials being photoluminescent at ambient temperature, comprising silicon grains of dimension of nanometers embedded in a silica matrix.