Effects of silica on the rheological and mechanical properties of the RTV silicone rubber foam

Room temperature vulcanization(RTV) silicone foam materials have been prepared by using five kinds of silica as reinforcing fillers.The effects of silica by different preparation methods and surface modification on the rheological property and foam mechanical properties of the based-compound during the silicone foam preparation were investigated in detail.The results indicated that the curing rate of the based-compound filled with the hydrophobic silica was faster than that filled with the hydrophilicity silica,in case of the same weight addition of the silica;the curing rate increased as the content of the fumed silica increased,whereas the curing rate decreased as the precipitation silica increased;the dispersity of the precipitated silica in the silicone rubber matrix is inferior to that of the fumed silica with hydrophobic modification.As the silica content increased,the holes size of the silicone rubber foam materials became smaller while the tensile-strength of them improved.