- All
- Product Name
- Product Keyword
- Product Model
- Product Summary
- Product Description
- Multi Field Search
Views: 1
The reinforcing filler commonly used in silicone rubber is primarily synthetic silicon dioxide, also known as white carbon black. White carbon black can be classified into fumed silica and precipitated silica.
a. Fumed Silica:
- The size, specific surface area, surface properties, and structure of silicon dioxide particles are influenced by factors such as the ratio of raw gases, combustion rate, and the residence time of SiO2 nuclei in the combustion chamber.
- Finer particles of fumed silica result in a larger specific surface area, enhancing reinforcement effects but potentially compromising processability. Conversely, coarser particles with smaller specific surface areas may provide weaker reinforcement effects but improved processability.
- Fumed silica is one of the most commonly used reinforcing agents in silicone rubber. Silicone compounds reinforced with fumed silica exhibit high mechanical strength and excellent electrical properties. Fumed silica can also be combined with other reinforcing or non-reinforcing agents to tailor materials for different applications.
b. Precipitated Silica:
- The properties of precipitated silica are influenced by precipitation conditions, such as acidity and temperature.
- Compared to silicone rubber compounds reinforced with fumed silica, those reinforced with precipitated silica may have slightly lower mechanical strength and poorer dielectric properties, especially after moisture absorption. However, they exhibit better resistance to heat aging, and the cost of compounding with precipitated silica is significantly lower.
- When high mechanical strength requirements for products are not critical, precipitated silica can be used alone or in combination with fumed silica to achieve desired material properties.
Understanding the distinctions between fumed silica and precipitated silica allows for the tailored formulation of silicone rubber compounds to meet specific performance requirements in different applications.
