It is an object of the invention to provide a rapid and economically viable process which is notable for efficient use of material, especially of the silylating agent, and by means of which organically modified lyo- or aerogels are obtained in a rapid and simple manner. This object is achieved by virtue of the invention providing a process for producing organically modified gels selected from lyo- and aerosols by (i) emulsifying a basic polar phase comprising water and starting materials for silicatic gels in a nonpolar phase containing a water-immiscible precursor for an active silylating agent, (ii) starting formation of gel and ageing by lowering the pH, and then (iii) starting the silylation and the exchange of solvent by lowering the pH. If the gels are aerogels, the gels provided can be used for thermal and/or acoustic insulation.

A curable composition includes at least one polyamine; an epoxy resin; and a silane-modified biosilica material. The silane-modified biosilica material is derived from rice husk and is present in the curable composition at a concentration of 0.01 to 10 wt. %, based on the total weight of the curable composition. The silane-modified biosilica material has an average particle size of 1 to 10 micrometers (m). A method of making a cured composite material from the curable composition.

A process for forming a porous spherical silica material is provided. The process comprises mixing an alkali silicate with a mineral acid at pH and temperature sufficient to form a silica sol, mixing the silica sol with an oil and a surfactant to form a water-in-oil type emulsion, adding an alkaline solution to the emulsion to form a gel, adding a demulsifying agent and heating to a temperature of from about 60 C. to about 90 C., and filtering, washing, optionally aging, and drying to obtain the porous spherical silica gel particles.