Discussion on the damping effect of methyl silicone oil and its research

Silicone oil is a liquid polyorganosiloxane with excellent high and low temperature resistance, chemical stability, shear resistance, viscosity temperature characteristics and high compression ratio. Damping products based on silicone oil are widely used in electronic and electrical equipment, high-rise buildings, bridges, and weapon platforms. A large number of related patents have been applied for abroad, while research in this area is still relatively limited in China.

Silicon oil based damping fluid has stable damping performance over a wide temperature and frequency range, which requires silicon oil to have a small viscosity temperature coefficient. In order to further improve the damping performance of silicone oil, it is often necessary to add a certain amount of filler to increase viscosity. The added filler is required to maintain non settling in silicone oil for a long time, and the viscosity of the damping liquid needs to change little within a certain shear rate range.

As the temperature increases, the viscosity change coefficient of methyl silicone oil with high viscosity increases accordingly. In addition, as the temperature increases, the viscosity of methyl silicone oil changes significantly in the low temperature range, while the change becomes smaller and smaller in the high temperature range. Therefore, methyl silicone oil is a suitable damping material for use at higher temperatures. The effect of molar mass and its distribution of methyl silicone oil on its viscosity temperature properties. The viscosity temperature coefficient of methyl silicone oil does not necessarily increase with the increase of viscosity. When the viscosity temperature coefficient of methyl silicone oil is the same, the distribution of molar mass of silicone oil with high viscosity is wide. It is contradictory that the viscosity temperature coefficient of methyl silicone oil increases with the increase of molar mass, but in fact, because the molar mass of general methyl silicone oil has a certain distribution and is polydispersity, which indicates that the viscosity temperature coefficient is also related to the distribution of molar mass, but the relationship between the viscosity temperature coefficient and the distribution of molar mass needs further study. Therefore, different viscosity methyl silicone oils can be used to prepare the required viscosity methyl silicone oil with lower viscosity temperature coefficient as the base oil for damping fluid according to different proportions.

In order to further improve the damping performance of the damping fluid, a certain amount of tackifying filler needs to be added to methyl silicone oil. Commonly used fillers include calcium carbonate, diatomaceous earth, white carbon black, and polymethylsilsesquioxane powder. Regarding the viscosity increasing effect of non silicon series fillers on damping fluid, ultrafine calcium carbonate has the best viscosity increasing effect on methyl silicone oil, which is closely related to the large specific surface area of ultrafine calcium carbonate. But even if ultrafine calcium carbonate is used as a tackifier, methyl silicone oil precipitation and layering still occur after being placed for more than 60 days, so this type of filler is not the most suitable for silicone oil tackifier.

The effect of silicon filler silica on the performance of damping fluid requires that the damping performance of the damping fluid be stable at different shear rates, which requires that the viscosity of the damping fluid change little within a certain range of shear rates. The effect of rotor speed on the dynamic viscosity of damping fluid containing different white carbon black and methyl silicone oil 1 as the substrate.

Conclusion: Methyl silicone oil with different viscosities can be used to prepare the required viscosity methyl silicone oil with lower viscosity temperature coefficient. Adding polymethylsilsesquioxane powder can prepare a damping solution with stable damping performance under a certain range of shear rates.