Characterisation Of Ormosil Composites Obtained By The Sol-Gel Process Using Positron Annihilation Lifetime Spectroscopy

An ormosil based matrix was prepared by the sol-gel method using tetramethoxysilane, TMOS, methyltrimethoxysilane, MTMS and trimethoxysilypropylmethacrylate, TMSPM, and water in a 1/1/4 molar ratio with CHl as a catalyst. Xerogels were obtained by hydrolysis and condensation of TMOS and tetraethoxysilane, TEOS. The samples were prepared in monolithic form and dried in air at 60 deg C for 3 weeks. A textural evaluation of samples of both systems was made using positron annihilation lifetime spectroscopy (PALS) and nitrogen gas adsorption (BET)> As the methods of analysis are based on different physical principles, the results are complementary leading to a good knowledge of the porosity of the samples studied.