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 N2 gas atmosphere their pore structures can be maintained up to 1000°C. This is due to the fact that Si-CH3 bond remains at high temperature. The 29Si MAS NMR spectra revealed that the intensity of T3 structural unit, whose origin is Si-C bonding, increased with an increase in methyltrimethoxysilane in a starting solution.