What are the main properties of fluororubber?

　　Good stability

　　Fluororubber has a high degree of chemical stability and is currently the best medium-resistance of all elastomers. 26 type fluororubber resistant to petroleum base oil, diester oil, silicone ether oil, silicic acid oil, resistant to inorganic acid, resistant to most organic, inorganic solvents, pharmaceuticals, etc., only resistant to low molecular weight ketones, ethers, Ester, not resistant to amine, ammonia, hydrofluoric acid, chlorosulfonic acid, phosphoric acid hydraulic oil. The properties of the 23 type fluorine rubber are similar to those of the type 26, and it is more unique. Its inorganic acid with strong oxidizing properties such as fuming nitric acid and concentrated sulfuric acid is better than the type 26, and is impregnated with 98% HNO3 at room temperature. Its volume expansion is only 13% to 15%.

　　High temperature resistance

　　The high temperature resistance of fluororubber is the same as that of silicone rubber, which is arguably the best in the current elastomer. 26-41 fluorine rubber can be used for a long time at 250 °C, short-term use at 300 °C; 246 fluorine rubber heat resistance is better than 26-41. The properties of 26-41 after air heat aging at 300 ° C × 100 hours are equivalent to those of 246 after 300 ° C × 100 hours hot air aging, and the elongation at break can be maintained at about 100%, and the hardness is 90 to 95 degrees. . Model 246 maintains good elasticity after hot air aging for 16 hours at 350 ° C, maintains good elasticity after hot air aging for 110 minutes at 400 ° C, and contains spray carbon black, thermal black carbon or carbon fiber after hot air aging for 110 minutes at 400 ° C. The elongation of the rubber increases by about 1/2 to 1/3, and the strength decreases by about 1/2, and still maintains good elasticity. The 23-11 type fluorine rubber can be used at 200 ° C for a long time and used at 250 ° C for a short period of time.

　　Aging resistance

　　Fluororubber has excellent weathering resistance and ozone resistance. It has been reported that the VitonA developed by DuPont has been performing satisfactorily after a natural storage for ten years, and there is no significant cracking in the air having an ozone concentration of 0.01% for 45 days. The type 23 fluororubber is also excellent in weather resistance and ozone resistance.

　　Vacuum performance

　　Type 26 fluororubber has excellent vacuum properties. The vacuum degassing rate of 246 fluororubber basic formula is only 37×10-6 liters/sec. cm 2.246 fluororubber has been successfully applied under vacuum conditions of 10-9 。.

　　Mechanical behavior

　　Fluororubber has excellent physical and mechanical properties. The type 26 fluororubber generally has a strength of between 10 and 20 MPa, an elongation at break of between 150 and 350%, and a tear strength of between 3 and 4 KN/m. The type 23 fluororubber has a strength between 15.0 and 25 MPa, an elongation of 200% to 600%, and a tear strength of 2 to 7 MPa. Generally, the fluororubber has a large compression set at a high temperature, but if compared with the same conditions, such as the compression set at 150 ° C for the same time, both the butyl rubber and the neoprene rubber are larger than the 26 fluoroelastomer. The compression deformation of the type 26 fluororubber at 200 ° C for 24 hours corresponds to the compression deformation of the butadiene rubber at 150 ° C for 24 hours.

　　Electrical performance

　　Type 23 fluororubber has good electrical properties and low hygroscopicity compared to other elastomers, and can be used as a good electrical insulating material. Type 26 rubber can be used at low frequency and low pressure.

　　Low gas permeability

　　Fluororubber has a relatively high solubility in gases, but the diffusion rate is relatively small, so the overall gas permeability is also small. It has been reported that the type 26 fluororubber is equivalent to butyl rubber and butyl rubber at 30 ° C for oxygen, nitrogen, helium and carbon dioxide gas, and is better than neoprene or natural rubber.

　　Low temperature performance

　　The low temperature performance of fluororubber is not good due to its own chemical structure, such as Tg > 0 ° C of type 23-11. The low temperature properties of the actually used fluororubber are usually expressed by the brittle temperature and the compression cold resistance coefficient. The formulation of the compound and the shape (such as thickness) of the product have a relatively large influence on the brittleness temperature. If the amount of the filler in the formulation is increased, the brittle temperature is sensitively deteriorated, the thickness of the product is increased, and the brittleness is also sensitively deteriorated.

　　Radiation resistance

　　The radiation resistance of fluororubber is one of the poorer in elastomers. Type 26 rubber exhibits cross-linking effect after radiation, and type 23 fluororubber exhibits cracking effect. The performance of 246 type fluororubber in the air at room temperature is drastically changed at a dose of 5 × 107 lun. The hardness increases by 1 to 3 degrees under the condition of 1 × 107 Å, the strength decreases by 20% or less, and the elongation decreases by 30% to 50%. Therefore, it is generally believed that the 246 type fluororubber can withstand 1 x 107 lun, and the limit is 5 x 107 lun.