Reinforcement of Rubber by In-situ Formed Silica

Silica with various surface morphology was synthesized by sol-gel reactions, tetraethoxysilane TEOS was used as a precursor of silica synthesis. To influence on morphology and surface characteristics the sol-gel reactions were modified by the presence of dispersing agents, anionic, cationic and non-ionic surfactants. Application of surfactants had an effect on the shape, morphology and size of synthesized silica particles. The reaction was conducted in decade (non-polar medium chosen as an elastomer model) and “in-situ” in two differ in polarity elastomers, ethylene-propylene rubber EPM, and hydrogenated butadiene-acrylonitrile rubber HNBR. The sol-gel reactions in elastomeric matrix were catalyzed by swelling the elastomers containing various amount of tetraethoxysilane TEOS in carbon dioxide or by the influence of the atmosphere of high moisture 70% or ammonia vapor. Silica particles formed in-situ in rubber matrix resulted in increase of tensile strength TS of rubber vulcanizates.