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Silica is divided into gas phase silica and precipitated silica.
1: The size, specific surface area, surface properties and structure of gas-phase silica particles are related to the ratio of raw gas, combustion speed, and the residence time of SiO2 cores in the combustion chamber.
The finer the gas-phase silica particles, the larger its specific surface area, the better the reinforcing effect, but the worse the operating performance. On the contrary, the coarser it is, the smaller the specific surface area is, the worse the reinforcing effect is, but the operability is better.
1: The size, specific surface area, surface properties and structure of gas-phase silica particles are related to the ratio of raw gas, combustion speed, and the residence time of SiO2 cores in the combustion chamber.
The finer the gas-phase silica particles, the larger its specific surface area, the better the reinforcing effect, but the worse the operating performance. On the contrary, the coarser it is, the smaller the specific surface area is, the worse the reinforcing effect is, but the operability is better.
Gas-phase silica is one of the most commonly used reinforcing agents for silicone rubber, and the rubber reinforced by it has high mechanical strength and good electrical properties of vulcanized rubber. Gas-phase silica and other reinforcing agents or weak reinforcing agent and use to produce different requirements of the use of rubber.
2：Precipitated silica
The performance of precipitated silica is affected by the precipitation conditions such as acidity and temperature.
Compared with the silicone rubber compound reinforced with gas-phase silica, the mechanical strength of the compound reinforced with precipitated silica is a little lower, and the dielectric properties, especially after moisture, are poorer, but the heat aging resistance is better, and the cost of the compound is lower. Poor, but heat aging performance is better, the cost of rubber mixing is much lower. When the mechanical strength of the product requirements are not high, precipitated silica can be used or make it and gas-phase silica. Black and used.
Compared with the silicone rubber compound reinforced with gas-phase silica, the mechanical strength of the compound reinforced with precipitated silica is a little lower, and the dielectric properties, especially after moisture, are poorer, but the heat aging resistance is better, and the cost of the compound is lower. Poor, but heat aging performance is better, the cost of rubber mixing is much lower. When the mechanical strength of the product requirements are not high, precipitated silica can be used or make it and gas-phase silica. Black and used.
Silica can be treated with suitable compounds to produce a hydrophobic surface. There are two main treatment methods: liquid-phase method and vapor-phase method. Liquid-phase method The conditions of liquid-phase method are easy to control, the product quality is stable and the treatment effect is good, but the process is complicated and the solvent needs to be recovered; the gas-phase method is simple, but the product quality is not stable enough and the treatment effect is poor. The vapor-phase method is simple, but the quality of the product is not stable enough and the treatment effect is poor.
