Patent ID: 11919776
Assignee: FUNDACION TECNALIA RESEARCH & INNOVATION
Field: Materials, metallurgy (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A process for preparing waterglass-based silica aerogels, wherein the process comprises:
(a) subjecting a certain amount of a vinyltrialcoxysilane to hydrolysis in the presence of water and an inorganic acid under stirring conditions to produce a hydrolyzed vinyltrialcoxysilane solution;
(b) treating a waterglass solution with an acidic cationic-exchange resin to produce a silicic acid solution;
(c) forming a sol phase by contacting the hydrolyzed vinyltrialcoxysilane solution with the silicic acid solution;
(d) forming a gel phase by adjusting the pH of the sol phase to a value in the range of from 4 to 6; and
(e) subjecting the gel phase to supercritical drying at a temperature in the range from 31° C. to 70° C. to produce an aerogel
wherein, prior to the supercritical drying of the gel phase of step (e) takes place, the water is exchanged with an organic solvent, and
wherein step (a) is carried out by first adding the vinyltrialcoxysilane over water, and then adding the inorganic acid.