VIBRATIONAL SPECTRAL STRUCTURAL-CHANGES FROM THE HYDROLYSIS POLYCONDENSATION OF METHYL-MODIFIED SILICATES .3. IR SPECTRAL COMPARISONS FOR CONDENSATES FROM THE BINARY METHYLTRIMETHOXYSILANE TETRAMETHOXYSILANE SYSTEM

Comparisons were made for the structures of condensates from the tetramethoxysilane (TMOS)/methyltrimethoxysilane (MTMS) system upon hydrolysis/polycondensation using infrared spectra. Spectral data indicated that the amount of silicate groups in the gel network possessing hydroxyl bonds increased, and that the gel structure approached that of highly hydroxylated silica as the TMOS content was increased in the precursor solution to form the gel. All generated condensates possessed four-membered (Si-O)4 rings as structural units within their structures. In contrast to studies for the TMOS/diethoxydimethylsilane (DEDMS)-derived gels, infrared spectral analysis did not indicate the presence of three-membered (Si-O)3 rings in the gels for this investigated series.