What is the reason for static electricity in silica gel?

Mixing silicone rubber usually produces static electricity during rubber mixing, especially in winter. Especially in this season, refining gas-phase silica gel on the open mill is simply dead from static electricity. Why does fumed silica gel easily generate static electricity, and the amount of static electricity is large?

Hybrid silicone rubber itself is insulating, with very large resistance and non-conductivity. The volume resistivity of mixed silicone rubber reaches1*1014Ω * cm, while the silica mesh of gas-phase silicone rubber is higher and the particles are finer, so the volume resistivity of gas-phase silicone rubber is 10- 100 times higher than that of mixed silicone rubber. Therefore, due to the friction of fumed silica gel and the high mesh number of silica, a lot of static electricity will be generated in the rubber mixing process. And in winter, due to the dry weather, the air humidity is greatly reduced, which leads to the greatly reduced air conductivity, so the electrostatic phenomenon is the most serious in the gas phase silica gel refining in winter. Moreover, the weather is cold during this period, and the rubber refiner wears a sweater and generates static electricity.