Structure of spherical porous silica particles derived from tetramethoxysilane and methyltrimethoxysilane

Spherical porous silica particles were synthesized by the sol-gel process from tetramethoxysilane and methyltrimethoxysilane in W/O emulsion. The difference in structure change by calcination is remarkable between air and nitrogen atmospheres. By calcination of the particles under N-2 gas atmosphere their pore structures can be maintained up to 1000 degrees C. This is due to the fact that Si-CH3 bond remains at high temperature. The Si-29 MAS NMR spectra revealed that the intensity of T-3 structural unit, whose origin is Si-C bonding,increased with an increase in methyltrimethoxysilane in a starting solution.