INFLUENCE OF THE CATALYSTS ON THE HYDROLYSIS-POLYCONDENSATION OF TETRAETHOXYSILANE STUDIED BY GC-MS

Gas-chromatography coupled with mass spectrometry (GC-MS) was used to investigate the hydrolysis and condensation of tetraethoxysilane (TEOS ) in the presence of different types of catalysts as: KCl, HF, CH3COOH and NH4OH. The study was carried out in concentrate solution and in t he presence of substoicheiometric amount of water, to obtain volatile molecular species, at least in the first stages of the process, and to detect oligomers formed in low quantity. Using GC-MS, direct evidence s concerning the major differences in the mechanism of hydrolysis-poly condensation of tetraethoxysilane in the presence of different catalys ts were obtained.