To distinguish the true silicone oil from the false silicone oil, we must first understand the silicone oil and its characteristics.

Silicone oil is a kind of polyorganosiloxane with chain structure of different polymerization degrees. It is prepared by hydrolysis of dimethyldichlorosilane with water to obtain primary polycondensation ring. The ring is cracked and rectified to obtain low ring. Then the ring, capping agent and catalyst are put together for polymerization to obtain mixtures with different polymerization degrees. Silicon oil can be prepared by vacuum distillation to remove the low boiling matter.

Features of silicone oil: It has excellent heat resistance, electrical insulation, weather resistance, hydrophobicity, physiological inertia and small surface tension. In addition, it also has low viscosity temperature coefficient, high compression resistance. Some varieties also have radiation resistance, no corrosion to metal, non-toxic, etc.

Function of silicone oil: commonly used as high-grade lubricating oil, shockproof oil, insulating oil, defoamer, release agent, polishing agent and vacuum diffusion pump oil. Among various silicone oils, methyl silicone oil is widely used as an important variety, followed by methyl phenyl silicone oil. In addition, there are ethyl silicone oil, methyl phenyl silicone oil, silicon oil containing nitrile, etc. Various functional silicone oils and modified silicone oils are mainly used for special purposes.

Identification of genuine and fake silicone oil:

1. Eye observation: Pseudo silicone oil will be turbid, smelly and smelly;

2. Test with fire: Use glass rod or iron rod dipped with a small amount of silicone oil to ignite. The white mineral oil can ignite and emit black smoke. Pure silicone oil will not burn when ignited with fire, and it is odorless, clear, transparent and non-toxic. The ignition point of silicone oil is 320 degrees.

3. Freezing point test method: silicone oil will not freeze at - 50 ℃, and false silicone oil will be turbid or frozen.

Advantages of silicone oil:

1. Excellent shear stability, with the function of absorbing vibration and preventing vibration transmission, it can be used as damping fluid.

2. Excellent thermal oxidation stability, such as thermal decomposition temperature>300 ℃, small evaporation loss (150 ℃, 30 days, evaporation loss is only 2%), oxidation test (200 ℃, 72h), small changes in viscosity and acid value.

3. Excellent electrical insulation, volume resistance, etc. will not change in the range of normal temperature~130 ℃ (but no water in the oil).

4. It is a non-toxic oil with low foaming property and strong anti foaming property, and can be used as defoamer.

5. The viscosity temperature performance is good among liquid lubricants, and the viscosity changes little in a wide temperature range. Its freezing point is generally less than - 50 ℃, and some are as high as - 70 ℃. After long-term storage at low temperature, the appearance and viscosity of its oil products have no change. It is a base oil with high temperature, low temperature and wide temperature range.

Disadvantages of silicone oil:

1. Low surface tension (easy to leak from the machine).

2. The gas solubility is high (it is difficult to design the gas seal device).

3. The thermal expansion coefficient of silicone oil is large (overpressure may occur).

4. The lubricity of silicon oil is poor, especially for steel friction pairs.

5. Certain hygroscopicity (water content higher than 100 × After 10-6, the electrical performance drops sharply)