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Ultrasound has been applied to organically modified silicates (ORMOSILs) solutions during gelation. A series of silica and polydimethylsiloxane (PDMS) composites have been prepared by the sol-gel method. Tetraethoxysilane (TEOS), PDMS, water and a HCl catalyst were mixed and exposed to 20 kHz ultrasonic radiation under different conditions. Ultrasonic radiation made it possible to obtain wet gels in 5 to 30 min. without solvent (e.g. alcohol, and THF). And exothermic reaction was observed due to hydrolysis and polycondensation of TEOS. The reaction process was examined by liquid state 2 9 Si NMR. Densities of obtained sono-ORMOSILs were observed to be higher than those produced by ordinary processes. Some sono-ORMOSIL samples demonstrated extremely low porosity and low specific surface areas.

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