Synthesis of nanosilica by the sol-gel method and its activity toward polymers

Applicability of the sol-gel method to fabricate polymer-silica composites has been briefly reviewed. The sol-gel method has been applied for synthesis of nanosilica in mineral and naphthenic oils and also in latexes of diene copolymers. A new silane precursor of nanosilica was prepared by transesterification of tetraethoxysilane with n-decyl alcohol and (aminopropyl) trimethoxysilane, in the presence of an emulsifier and a stabilizer. Transparent sols of nanosilica in oils were obtained as the main product, accompanied by few % of dispersions of SiO2. Microscope and AFM studies confirmed the presence of particles of nanometric size. The studies are continued in order to optimize reaction conditions and minimize the size of SiO2 particles. Nanosilica sols are applied for modification of properties of elastomers and other polymers. New hybrid modifiers of general formula X(Me2SiO)4R have been prepared. Their chemical structures were confirmed by spectroscopic methods: FT-IR and NMR (H-1, Si-29-). These new products have been applied for synthesis of modified silica nanoparticles in elastomers matrices (in situ).