Silicone oil is a linear polysiloxane product that remains liquid at room temperature.

Generally divided into methyl silicone oil and modified silicone oil two categories. The most commonly used silicone oil-methyl silicone oil, also known as ordinary silicone oil, its organic groups are all methyl, methyl silicone oil has good chemical stability, insulation, hydrophobicity. It is obtained by hydrolysis of dimethyldichlorosilane with water, and the low ring is obtained by pyrolysis and rectification of the ring, then put the ring, head, catalyst together to adjust polymerization can be a mixture of various degrees of polymerization, by vacuum distillation to remove the low-boiling materials can be prepared silicone oil. The harmfulness of silicone oil: (1) the lubricity of silicone oil is not good, especially to the steel friction pair. (2) silicone oil has a high Coefficient of thermal expansion (which may cause overpressure problems) . (3) high gas solubility (difficult to design gas sealing device) . (4) certain hygroscopicity (electrical performance drops sharply after water content is higher than 100 × 10 ~ (-6)) . (5) low surface tension (easy to leak from the machine) 

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