Adding filler can improve the mechanical properties of silicone rubber, and the amount of filler has a great influence on the electrical properties and mechanical properties of silicone rubber. The filler is generally an inorganic substance, mainly white carbon black, titanium dioxide, quartz powder, kaolin, micronized talc, precipitated calcium carbonate and the like. The reinforcing fillers used in silicone rubber are mainly white carbon black, including gas phase and precipitated silica. Due to the low intermolecular cohesive energy density of silicone rubber, the tensile strength of vulcanizate is only about 0.35 MPa, which has almost no use value. It needs to be reinforced by gas phase method or precipitation method to improve the mechanical properties of vulcanized silicone rubber. With the increase of the amount of silica, the tearing and tensile strength of the vulcanized silicone rubber increased, the hardness gradually increased and then decreased, and the volume resistivity gradually decreased.
The organosilicon compound itself has good insulation, and the addition of the filler affects the molecular chain, so that the resistivity of the vulcanized silicone rubber decreases. However, due to the reinforcing effect of the filler, the mechanical properties of the silicone rubber can be improved, and the hardness of the silicone rubber is improved. However, if the filler is added too much, the crosslinking between the polymer molecular chains is affected, so that the hardness of the silicone rubber is lowered.