Fluorosilicone material is an emerging material developed on the basis of organic silicon materials and organic fluorine materials. Due to the silicon-oxygen bonds in its main chain structure and the fluorine-containing alkyl groups in the side chain structure, fluorosilicone polymer has both the high-temperature chemical corrosion resistance and oil resistance of fluorocarbon rubber and the excellent high-temperature tensile retention and low-temperature retention of silicone rubber. Due to its soft properties, foreign experts believe that fluorosilicone rubber is the only oil-resistant and solvent-resistant synthetic rubber used in a wide temperature range of -68°C to 232°C. It is an indispensable special material in the modern military industry, aerospace industry, transportation industry such as automobiles and ships, petrochemical industry, and medical and health sectors such as artificial organs.
Characteristics of fluorosilicone rubber
1. The O-Si-O bond angle is large and easy to rotate freely → excellent low temperature performance
2. High Si-O bond energy → good high temperature resistance
3. The main chain is covered by -CH2CH2CF3 → good oil resistance
4. The surface of the material is covered with CF3 groups → extremely low surface tension
5. The side group CH2CH2 contains a certain degree of dipole → good air tightness
Oil, solvent and chemical resistance
For aliphatic, aromatic and chlorinated hydrocarbon solvents, various petroleum-based fuel oils, lubricating oils, hydraulic oils and certain synthetic oils (such as diester lubricating oils, silicate hydraulic oils, etc.) are used at normal and high temperatures. The stability is very good and the elasticity is maintained. Under oil immersion conditions, the maximum operating temperature can reach 180°C. It has good stability at room temperature and high temperature, and can be used for long-term use in the range of -50℃~+200℃, and for short-term use at 250℃.
Compared with methyl vinyl silicone rubber, fluorosilicone rubber has extremely excellent oil resistance, solvent resistance, and chemical resistance; even compared with fluororubber, its oil resistance and solvent resistance are also good. It shows excellent durability after immersion in the same medium, temperature and time. It can be said that fluorosilicone rubber is the only elastomer that can withstand non-polar media at -68°C ~ 232°C.
Fluorosilicone rubber also has relatively good resistance to methanol-containing gasoline. Even in a gasoline/methanol (85vol%/15vol%) mixed system, the hardness, tensile strength, and volume of the vulcanized rubber change very little. After 500 hours of use, the After the immersion test, there was almost no change in various physical properties.
heat resistance
The high temperature decomposition of fluorosilicone rubber is the same as that of silicone rubber, namely: side chain oxidation, main chain breakage, side chain thermal decomposition and various composite reactions. Since the decomposition products can also cause the main chain to break, the heat resistance is usually worse than that of silicone rubber, and it has begun to oxidize and age at a temperature of 200°C. However, by adding a small amount of heat stabilizers such as iron, titanium, rare earth oxides, etc., it can be significantly improved, and it has sufficient heat resistance even at a high temperature of 250°C.
The effect of temperature on fluorosilicone rubber is greater than that of silicone rubber, but less than that of fluororubber. Foreign studies have also studied the service life of fluorosilicone rubber under the conditions of 150℃×2000h, 175℃×5000h, and 200℃×4000h. The results are second only to methyl vinyl silicone rubber.
Cold resistance
Fluorosilicone rubber, like ordinary silicone rubber, has good low-temperature properties. Since fluorosilicone rubber is a linear polymer composed of soft Si-O as the main chain, its low temperature characteristics are better than those of fluororubber with C-C as the main chain. Among them, fluorosilicone rubber (AFS-R-M1200) has better low-temperature characteristics, with a brittleness temperature as low as -70°C, while general fluororubber is about -30°C.
Electrical properties, radiation resistance
The electrical properties of fluorosilicone rubber are similar to ordinary silicone rubber, but what is particularly valuable is that it changes very little under harsh conditions such as high temperature, low temperature, moisture, oil, solvents, chemicals, and ozone. The radiation resistance of fluorosilicone rubber is not outstanding, but its radiation aging resistance is better than that of methyl vinyl silicone rubber.
Other features
Fluorosilicone rubber has excellent weather aging resistance and still maintains good performance even after 5 years of exposure. Ozone is one of the most generated gases when elastomers age, but no cracks or cracks have been found in fluorosilicone rubber after dynamic or static tests.
In addition, fluorosilicone rubber's mildew resistance, physiological inertness, and anticoagulant properties are also very good.
Low pressure variable fluorosilicone compound
