Dyachenko A. The interaction of organosiloxanes with the of fumed silica modified with metal oxides

The dissertation is devoted to the research of the influence of metal oxide phase supported to the fumed silica surface on chemical transformation, which take place within organosilicon compounds depending on temperature. It has been experimentally (IR, TPD MS, DTA, TG) found that the presence of metal oxide nanostructures on the surface of the fumed silica promotes the decrease of the temperature of Si-C bond destruction and methane elimination, at high temperatures the presence of metal oxide on the silica surface promotes the break of the siloxane bond, which causes partial depolymerization of the adsorbed polydimethylsiloxane. The reaction of hexamethyldisilazane with the silica surface containing titanium and vanadium oxide phases has been studied. It has been determined that the chemisorption of hexamethyldisilazane on the surface of the sample coated with vanadium oxide occurs through the reaction with free silanol groups as well as with breaking of SiO-V bond. The value of activation energy ofthis process is very similar for all samples, consequently, metal oxide phase applied to the silica surface does not considerably influence the chemisorption of hexamethyldisilazane.