Adding fillers can improve the mechanical properties of silicone rubber, and the amount of fillers has a greater impact on the electrical and mechanical properties of silicone rubber. Fillers are generally inorganic substances, mainly white carbon black, titanium dioxide, quartz powder, kaolin, micronized talc, and precipitated calcium carbonate. The reinforcing filler used in silicone rubber is mainly white carbon black, including gas phase method and precipitation method white carbon black. Due to the low intermolecular cohesive energy density of raw silicone rubber, the tensile strength of the vulcanized rubber is only about 0.35MPa, which is almost of no use value. It needs to be reinforced with gas phase method or precipitation method white carbon black to improve the mechanical properties of vulcanized silicone rubber. With the increase in the amount of white carbon black, the tear and tensile strength of the vulcanized silicone rubber increase, the hardness gradually increases and then decreases, while the volume resistivity gradually decreases. 

Since the organosilicon compound itself has good insulating properties, the addition of fillers will affect the molecular chain, which will reduce the resistivity of the vulcanized silicone rubber. 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 can be increased. However, if the filler is added too much, the crosslinking between the polymer molecular chains will be affected, and the hardness of the silicone rubber will be reduced.