Comparisons among some tetraalkoxysilanes in the hydrolytic precipitation of silica into elastomeric networks

Four tetraalkoxysilanes Si(OR)4 were absorbed into networks of polydimethylsiloxane and then hydrolyzed, using a variety of catalysts, to give reinforcing silica particles. On the basis of the amount of silica precipitated and the extent of reinforcement, the (decreasing) order of effectiveness was found to be tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and tetramethoxysilane.