Galván Preparation of sol-gel hybrid materials from 3- methacryloxypropyltrimethoxysilane and tetramethylorthosilicate: study of the hydrolysis and condensation reactions

Organic-inorganic hybrid materials suitable for the development of sol-gel coatingsfor metallic surfaces were prepared by hydrolysis and condensation of γ-methacryloxypropyltrimethoxysilane (MAPTMS) and tetramethylorthosilicate (TMOS). The hydrolysis of MAPTMS/TMOS was carried out in an ethanol/water solution. The prehydrolysis stage of MAPTMS/TMOS system was monitored by Fourier Transformer Infrared Spectroscopy (FTIR) and liquid-state Si and CNuclear Magnetic Resonance(Siand CNMR).FTIR analysis indicated that the hydrolysis of MAPTMS/TMOS was accomplished as far as the (Si-OMe) band corresponds to unhydrolyzed silane disappeared. The concentration of the alkoxy groups and the extent of self-condensation of mono-, di-, and tri-substituted siloxanes(T species) in the sol were estimated by using liquid-state Si NMR spectroscopy. The hydrolysis of the prepared sol was also evaluated by liquid state C NMR spectroscopy. The results indicated that under the adopted synthesis strategy conditions, the hydrolysis process require four hours to be completed.