Polytetrafluoroethylene ---- performance chapter
PTFE has very high chemical resistance, for example, in concentrated sulfuric acid, nitric acid, hydrochloric acid, and even boiling in aqua regia, its weight and performance are not changed, and almost insoluble in most solvents, only slightly soluble in full alkane (about 0.1g/100g) above 300 ℃. Polytetrafluoroethylene does not absorb moisture, non-combustible, extremely stable to oxygen and ultraviolet light, so it has excellent weather resistance.
It is worth noting that PTFE cannot withstand extremely strong reducing atmospheres
Molten alkali metal, ammonia alkali solution (alkali metal dissolved in liquid ammonia), some fluoride (such as TFA), naphthalene sodium salt, etc. can quickly corrode PTFE products
PTFE in a wide range of frequency dielectric constant and dielectric loss are very low, and breakdown voltage, volume resistivity and arc resistance are high.
The radiation resistance of polytetrafluoroethylene is poor (104 rads), and degradation is caused by high-energy radiation, and the electrical and mechanical properties of the polymer are significantly reduced.
Polytetrafluoroethylene is produced by the free radical polymerization of tetrafluoroethylene. The industrial polymerization reaction is carried out in the presence of large amounts of water with stirring to disperse the heat of reaction and to facilitate temperature control. Polymerization is generally carried out at 40 to 80°C and 3 to 26 kg force/cm2 pressure, and can be initiated by inorganic peroxides and organic peroxides, or by redox initiation systems. Dispersion polymerization requires the addition of perfluorinated surfactants, such as perfluorooctanoic acid or its salts.
1. FEP can also be made into heat shrinkable tubes, which can be used for coating transfer rollers in printing presses. 2.High surface quality can prevent print adhesion, contamination and discoloration. 3. In the medical industry, FEP tubes are mainly used as catheters or in the field of endoscopy. 4. It also prevents contamination of the delivered liquid during the injection process. 5. Therefore, the biocompatibility of FEP for medical use is also excellent. 6. FEP can be sterilized by all conventional methods.
Heat exchangers are used in a wide range of applications in industries such as air conditioning, power plants, oil refineries and internal combustion engines. You may not know that you are familiar with heat exchangers. Take for example the radiator in your car. Heat exchangers keep your equipment cool and prevent overheating and malfunction. You may have seen someone open the hood of their car on the side of the road and smoke comes out as a result of a radiator failure.
PTFE material has the smallest surface tension and inertness among solid materials and does not adhere to any substance. PTFE material has the lowest coefficient of friction, excellent self-lubrication, and also has excellent resistance to high and low temperatures, which makes it very widely used in applications such as the manufacture of non-stick pan anti-stick. PTFE is also used in rollers and other parts, as a guide, and as a material for the production of non-stick pans.
1. PTFE white curly staple fiber is generally manufactured using the membrane splitting method, fiber strength is greater than the brown fiber produced by the emulsion spouting method, fiber can also be used to add color technology as needed to make a variety of colored fibers. It is suitable for high temperature environment, excellent chemical stability, low shrinkage rate, anti-aging and other characteristics.
Polytetrafluoroethylene (F4, PTFE) has a series of excellent performance: high temperature resistance - long-term use temperature 200 ~ 260 degrees, low temperature resistance - still soft at -100 degrees; corrosion resistance - can resist aqua regia and all organic solvents; weather resistance - The best aging life in plastic; high lubrication - with the smallest coefficient of friction in plastic (0.04); non-stick - with the smallest surface tension in solid materials without adhesion to any material; non-toxic - with physiological inertia; excellent electrical properties, is the ideal C-class insulation material.
The coefficient of friction of PTFE is extremely small, only 1/5 of that of polyethylene, which is an important characteristic of perfluorocarbon surfaces. Due to the extremely low intermolecular forces between fluorine-carbon chains, PTFE has non-stick properties.