Silicone rubber has the characteristics of high and low temperature resistance, weather resistance, ozone resistance, corona resistance, good electrical insulation performance, surface water repellency, low compression deformation rate, and is a unique variety of rubber. Because of these good characteristics, it has been more and more widely used in electrical insulation systems.

At present, most composite insulator manufacturers at home and abroad use methyl vinyl silicon rubber filled with more aluminum hydroxide as outdoor insulation materials. In the formula of high temperature vulcanized silicone rubber, aluminum hydroxide has a great influence on the mechanical properties, electrical properties, hydrophobicity and flame retardancy of the product. The results show that adding aluminum hydroxide filler can improve the properties of silicone rubber such as leakage marking resistance, electric erosion resistance, arc resistance and flashover resistance. However, aluminum hydroxide as an inorganic filler and organic polymer silicone rubber body have great differences in physical form and chemical structure, and the affinity between the two is poor, which limits the amount of aluminum hydroxide as a filler in silicone rubber.

Effect of aluminum hydroxide particle size on mechanical properties of silicone rubber

When the particle size of aluminum hydroxide is too small, because the particles are easy to agglomerate, it is difficult to evenly disperse in the silicone rubber system, resulting in poor mechanical properties. When the second particle size is too large, due to the small specific surface area, the mechanical properties are also low, and only when the particle size is moderate, its mechanical properties are better.

Effect of aluminium hydroxide particle size on electrical properties of silicone rubber

The results show that with the increase of aluminum hydroxide particle size, the volume resistivity of silicone rubber increases gradually, and the dielectric loss and dielectric constant decrease gradually. This shows that from the effect of particle size on the electrical properties of silicone rubber, filling slightly larger particle size aluminum hydroxide is beneficial to the electrical properties of silicone rubber.

Effect of aluminium hydroxide particle size on hydrophobic properties of silicone rubber

From the effect of particle size on the hydrophobic properties of silicone rubber, the filling of aluminum hydroxide with smaller particle size is beneficial to the hydrophobic properties of silicone rubber. The main reason is that within a certain particle size range, the smaller the particle size, the easier it is to be wrapped by raw rubber, so as the filling particle size decreases, the hydrophobicity increases.

Effect of aluminum hydroxide particle size on flame retardancy of silicone rubber

When the particle size of aluminum hydroxide is small, aluminum hydroxide is difficult to distribute evenly in the silicone rubber system, resulting in poor flame retardant, and when the particle size is too large, the compatibility of aluminum hydroxide and silicone rubber organic system is poor, which can also lead to poor flame retardant. Therefore, in order to achieve better flame retardant performance, a moderate particle size must be selected.