Good stability
Fluorosilicone has high chemical stability and is the best medium resistance among all elastomers at present. Fluorosilicone products are resistant to petroleum based oil, double ester oil, silicone ether oil and silicic acid oil, inorganic acid, most organic and inorganic solvents and drugs, only low molecular ketones, ethers and esters, and amine, ammonia, hydrofluoric acid, chlorosulfonic acid and phosphoric acid hydraulic oil. The medium performance of type 23 fluoroadhesive is similar to that of type 26, and it is more unique. Its resistance to strong oxidizing inorganic acids such as fuming nitric acid and concentrated sulfuric acid is better than that of type 26. After immersion in 98% HNO3 at room temperature for 27 days, its volume expansion is only 13% ~ 15%.
High temperature resistance
The high temperature resistance of fluorosilicone is the same as that of silicone rubber, which can be said to be the best elastomer at present. 26-41 fluorine glue can be used for a long time at 250 ℃ and for a short time at 300 ℃; 246 fluorine glue has better heat resistance than 26-41. At 300 ℃ × Physical properties of 26-41 after 100 hours of air thermal aging and 300 ℃ × After 100 hours of hot air aging, the performance of type 246 is equivalent, its elongation at break can be maintained at about 100%, and its hardness is 90 ~ 95 degrees. Type 246 maintains good elasticity after 16 hours of aging in hot air at 350 ℃, and 110 minutes after aging in hot air at 400 ℃. After 110 minutes of aging in hot air at 400 ℃, the elongation of the compound containing spray carbon black, hot cracking carbon black or carbon fiber increases by about 1/2~1/3, and the strength decreases by about 1/2, still maintaining good elasticity. 23-11 fluorine glue can be used for a long time at 200 ℃ and for a short time at 250 ℃.
Aging resistance
Fluorosilicone lined fuel tube has excellent weather aging resistance and ozone resistance. It is reported that the performance of vitona developed by DuPont is still satisfactory after ten years of natural storage, and there is no obvious cracking after 45 days in the air with ozone concentration of 0.01%. The weather aging resistance and ozone resistance of type 23 fluorosilicone are also excellent.
Vacuum performance
Type 26 fluorosilicone has excellent vacuum performance. The vacuum outgassing rate of vulcanizate with 246 fluorosilicone basic formula is only 37 × 10-6 Torr L / s. cm2. 246 fluorosilicone has been successfully applied under vacuum conditions of 10-9 Torr.
Mechanical properties
Fluorosilicone has excellent physical and mechanical properties. The general strength of type 26 fluorosilicone is 10 ~ 20MPa, the elongation at break is 150 ~ 350%, and the tear strength is 3 ~ 4KN / m. The strength of type 23 fluorosilicone is 15.0 ~ 25MPa, the elongation is 200% ~ 600%, and the tear strength is 2 ~ 7MPa. Generally, the compression set of fluorosilicone at high temperature is large, but if compared with the same conditions, such as the compression set at 150 ℃ for the same time, both butadiene and chloroprene rubber are larger than type 26 fluorosilicone, and type 26 fluorosilicone is at 200 ℃ × The compression deformation under 24 hours is equivalent to that of butadiene rubber at 150 ℃ × 24-hour compression deformation.
Electrical properties
Type 23 fluorosilicone has better electrical properties and lower moisture absorption than other elastomers. It can be used as a better electrical insulation material. Type 26 rubber can be used under low frequency and low pressure.
Low air permeability
The solubility of fluorosilicone to gas is relatively large, but the diffusion rate is relatively small, so the overall air permeability is also small. According to reports, the air permeability of 26-type fluorosilicone to oxygen, nitrogen, helium, and carbon dioxide gas at 30 °C is comparable to that of butyl rubber and butadiene rubber, and is better than that of neoprene and natural rubber.
Low temperature performance
The low temperature performance of fluorosilicone is not good, which is due to its own chemical structure, such as Tg>0℃ of type 23-11. The low temperature performance of fluorosilicone actually used is usually expressed by the brittleness temperature and the compression cold resistance coefficient. The formula of the rubber compound and the shape of the product (such as thickness) have a great influence on the brittleness temperature. If the amount of filler in the formula increases, the brittleness temperature is sensitively deteriorated, the thickness of the product increases, and the brittleness mixing degree is also sensitively deteriorated.
Radiation resistance
The radiation resistance of fluorosilicone is one of the poorer elastomers. Type 26 rubber exhibits a cross-linking effect after irradiation, while type 23 fluorosilicone exhibits a cracking effect. The performance of 246 type fluorine rubber changes drastically under the dose of 5 × 107 lon in the air at room temperature. Under the condition of 1 × 107 lon, the hardness increases by 1~3 degrees, the strength drops below 20%, and the elongation decreases by 30%~50% , so it is generally believed that 246-type fluorosilicone can withstand 1 × 107 lons, and the limit is 5 × 107 lons.
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