Adding fillers can improve the mechanical properties of silicone rubber, and the amount of fillers has a significant impact on the electrical and mechanical properties of silicone rubber. Fillers are generally inorganic substances, mainly including white carbon black, titanium dioxide, quartz powder, kaolin, micro powdered talc, and precipitated calcium carbonate, etc. 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, the tensile strength of silicone rubber raw rubber is only about 0.35MPa, which has almost no practical value. Therefore, it is necessary to use gas-phase or precipitation method white carbon black for reinforcement to improve the mechanical properties of vulcanized silicone rubber. As the amount of white carbon black increases, the tear and tensile strength of the vulcanized silicone rubber increase, the hardness gradually increases and then decreases, and the volume resistivity gradually decreases. 
Organic silicon compounds themselves have good insulation properties, and the addition of fillers can affect the molecular chains, resulting in a decrease in the electrical resistivity of vulcanized silicone rubber. However, due to the reinforcing effect of fillers, the mechanical properties of silicone rubber can be improved, resulting in an increase in its hardness. However, if too much filler is added, it will affect the cross-linking between polymer molecular chains, leading to a decrease in the hardness of silicone rubber.
Click to view more organic silicon products