The new factory's silica is not easy to use" and "the used old silica will be deteriorated?

It is inaccurate to assume in general terms that “new silica is not easy to use” and “the use of stored old silica will deteriorate”.

For the newly produced fumed silica, the white carbon residue on the surface of the silica particles is extremely low in the state in which the surface is not sufficiently contacted and adsorbed in the air due to the high temperature burning of the silica particles. The reinforcing effect is weak. If the new fumed silica is directly treated with silazane, the treatment effect is not obvious because the surface of the silica particles lacks the silicon hydroxyl group reacting with the silazane. The fumed silica stored at an appropriate time, after adsorbing moisture, generates an appropriate amount of silanol on the surface of the silica particles, and exhibits its inherent reinforcing effect. Under this condition, the surface modification treatment is carried out. expected result.

For the new precipitated silica, the drying temperature is not too high, and the surface of the silica particles still retains silicon hydroxyl groups, thus reinforcing the effect. It can be used directly for silazane treatment, and it can also achieve the desired treatment effect. However, after many years of long-term storage, the precipitated white carbon black is used for reinforcing the silicone rubber, and the reinforcing effect is deteriorated. The vulcanized silicone rubber not only has poor mechanical strength, but also has poor heat resistance and dielectric properties.