The use of fumed silica can be divided into silicone materials and other fields. The amount of fumed silica in silicone materials accounts for nearly 60% of the total amount of fumed silica. Silicone rubber is the most widely used material in silicone materials, and the amount of fumed silica can be more than 50%. Fumed silica mainly plays a reinforcing role in HVT silicone rubber. Because the molecular chain of silicone rubber is very flexible and the interaction force between chains is weak, the strength of unreinforced silicone rubber is very low, and the strength of silicone rubber reinforced by fumed silica can be increased up to 40 times.

Generally, the smaller the particle size, the higher the specific surface area, the higher the structure, the better the reinforcement effect, and the higher the strength and hardness of the vulcanizate. The change of tear strength of vulcanizate is similar to that of tensile strength, which increases with the increase of the reinforcing property of fumed silica, first increases with the increase of the amount of fumed silica, and then decreases slightly after reaching the peak value.

In the mixing process, adding structure control agent or selecting fumed silica after surface treatment can reduce the number of surface hydroxyl, reduce the number of hydrogen bond formed with silicone rubber, shorten the mixing time of the rubber, increase the plasticity, reduce the structural effect, improve the processing performance and storage stability.

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