Effects of Silica on Properties of the RTV-2 Silicone Rubber Sealant

Different kinds of silica as reinforcing fillers were used to fill in two-component room temperature vulcanization(RTV-2) silicone rubber sealant.The effects of different kinds of silica and hydrophobic silica adding dosage on the rheological property,mechanical properties,thermal aging properties and ASTM3# oil resistance of silicone rubber sealant were studied.The research showed that the RTV-2 silicone rubber sealant filled with the hydrophobic silica has better rheological property.The curing rate of the based-compound filled with the hydrophobic silica was slower and more stable than that filled with the hydrophilicity silica.The mechanical properties and thermal aging properties of silicone rubber sealant filled with the other fillers was inferior to that filled with the hydrophobic silica,but the ASTM3# oil resistance performance on the contrary.As the silica content increased,the mechanical properties and ASTM3# oil resistance of silicone rubber sealant were improved while the thermal aging properties of them reduced.