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 tetra methoxysilane (TMOS)/methyltrimethoxysilane (MTMS) system upon hydroly sis/polycondensation using infrared spectra. Spectral data indicated t hat the amount of silicate groups in the gel network possessing hydrox yl bonds increased, and that the gel structure approached that of high ly hydroxylated silica as the TMOS content was increased in the precur sor solution to form the gel. All generated condensates possessed four -membered (Si-O)4 rings as structural units within their structures. I n contrast to studies for the TMOS/diethoxydimethylsilane (DEDMS)-deri ved gels, infrared spectral analysis did not indicate the presence of three-membered (Si-O)3 rings in the gels for this investigated series.