1. Increase hardness and resist friction
Silicon dioxide itself has a high hardness. When it is added to silicone rubber, it is like putting a hard "armor" on the surface of silicone rubber. In daily use, when silicone rubber products rub against other objects, this hard surface given by silica can withstand part of the friction and reduce the direct wear of silicone rubber molecular chains. For example, high-temperature vulcanized silicone rubber containing silica used in automotive seals can still maintain good sealing performance and extend service life in a long-term friction environment.

2. Improve the surface and reduce friction
Silicon dioxide can also improve the surface properties of silicone rubber, making the relatively rough silicone rubber surface smoother. A smooth surface means a lower coefficient of friction with other objects, just like adding a layer of lubricant to the surface of silicone rubber products. This not only helps to reduce wear, but also improves the smoothness and flexibility of silicone rubber products during use. For example, silicone rubber parts in some precision instruments can reduce wear during frequent activities due to the effect of silica, ensuring the precise operation of the instrument.