On the basis of maintaining the excellent properties of silicone materials such as heat resistance, cold resistance, high voltage resistance and weather aging resistance, FVMQ fluorosilicone O-ring has excellent hydrogen resistant solvents, oil resistance, acid and alkaline resistance and lower surface performance due to the introduction of fluorine containing groups.
Features of fluorosilicone rubber:
1. Oil resistance, solvent resistance and chemical resistance
Compared with methyl vinyl silicone rubber, fluorosilicone rubber has excellent oil resistance, solvent resistance and chemical resistance; Even compared with fluororubber, 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 resistant to non-polar medium at – 68 ℃~232 ℃. The resistance of fluorosilicone rubber to methanol containing gasoline is also good. Even in the gasoline/methanol mixed system, the hardness, tensile strength and volume of its vulcanizate have little change. After a long immersion test of 500h, the physical properties of its vulcanizate have almost no change.
2. Heat resistance
The high-temperature decomposition of fluorosilicone rubber is the same as that of silicone rubber, namely, side chain oxidation, main chain fracture, side chain thermal decomposition and various composite reactions. As the decomposition products will also cause the main chain to break, the heat resistance is generally worse than that of silicone rubber, and the oxidation aging has started at 200 ℃. However, it can be significantly improved by adding a small amount of heat stabilizers such as iron, titanium and rare earth oxides, and it has sufficient heat resistance even at 250 ℃. The influence of temperature on fluorosilicone rubber is greater than that of silicone rubber, but smaller than that of fluorosilicone rubber. The foreign countries also studied the fluorosilicone rubber at 150 ℃ × 2000h、175℃ × 5000h、200℃ × The service life under 4000h is second only to methyl vinyl silicone rubber.
3. Cold resistance
Like ordinary silicone rubber, fluorosilicone rubber has good low-temperature performance. As fluorosilicone rubber is a linear polymer with 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, the low temperature characteristics of fluorosilicone rubber (LS-2370U) are better, and the brittleness temperature is as low as – 89 ℃, while that of general fluorosilicone rubber is about – 20~- 30 ℃.
4. Electrical performance and radiation resistance
The electrical properties of fluorosilicone rubber are similar to those of ordinary silicone rubber, but the most valuable thing is that it has little change under high temperature, low temperature, humidity, oil, solvent, chemicals, ozone and other harsh conditions. The radiation resistance of fluorosilicone rubber is not outstanding, but its radiation aging resistance is better than that of methyl vinyl silicone rubber.
5. Physical and mechanical properties
Like ordinary silicone rubber, fluorosilicone rubber has low mechanical strength (especially tear strength). Therefore, improving and increasing the strength of fluorosilicone rubber is also an important research topic.
6. Other characteristics
The weather resistance of fluorosilicone rubber is very good, even after 5 years of exposure, it still has good performance. Ozone is one of the most generated gases when the elastomer is aged, but no cracks or cracks are found in fluorosilicone rubber after dynamic or static tests. In addition, the mold resistance, physiological inertia and anticoagulation of fluorosilicone rubber are also very good.