Polytetrafluoroethylene CAS 9002-84-0

Polytetrafluoroethylene (PTFE) is commonly known as the king of plastics. It is a polymer compound formed by the addition polymerization of tetrafluoroethylene. It is available in three forms: granular, powder and dispersion. The density of the solid is 2.25g/cm3. It is white, translucent and heat-resistant. The operating temperature can be between -75℃ and 250℃. It can decompose when heated to 415℃, and the generated gas is harmful to humans. It does not react with any chemical except molten metal sodium and liquid fluorine.

In chemical production, it is used as equipment lining, distillation tower, bellows, pumps, valves, sealing gaskets, etc.; in the mechanical industry, it is used as seals, piston rings, rotating bearings, etc.; in the electronics industry, it is used for electronic computer signal line insulation, cable insulation, high-frequency electronic instrument insulation and the manufacture of high-frequency cables, high-precision capacitors, wires, etc.; in the construction industry, it is used to make large pipelines, steel structure roof trusses, bridges, etc.; in the textile industry, it can be used as anti-stick rollers, conveyor belts impregnated with polytetrafluoroethylene, etc.; in the pharmaceutical industry, it is used as artificial blood vessels, artificial heart and lung devices, disinfection protectors, etc.; in the plastic and food industries, it is used as a demolding agent. In 1935, R.J. Praskett found that when a container was filled with tetrafluoroethylene when studying the refrigerant of fluorocarbon, white solids appeared on the wall. This was the first discovered polytetrafluoroethylene. In 1941, DuPont of the United States conducted a pilot test and began industrial production in 1950.

1. High chemical stability
   PTFE can withstand the effects of all strong acids, strong bases, strong oxidants, reducing agents, etc. except molten alkali metals, fluorine elements and strong fluorinated media and sodium hydroxide above 300°C. Its chemical corrosion resistance exceeds that of precious metals, glass, ceramics, enamels and alloys, and even uranium fluoride, a strong corrosive agent in the atomic energy industry, does not corrode it.
2. Wide range of operating temperature
   PTFE can be used in a wide range of -250 to 260°C, and can still maintain a certain degree of flexibility even at an ultra-low temperature of -260°C; at 260°C, its breaking strength remains at about 5MPa (about 1/5 of room temperature), and its yield strength reaches 1.4MPa.
3. Outstanding non-stickiness
   PTFE is currently a solid material with the smallest surface energy, with a surface tension of only 0.019N/m. Almost all solid materials cannot adhere to its surface, and only liquids with a surface tension below 0.02N/m can completely infiltrate its surface.
4. Abnormal lubricity
   Due to the small mutual attraction between PTFE macromolecules and the small attraction of the surface to other molecules, its friction coefficient is very small, and it is the self-lubricating material with the lowest friction coefficient found so far.
5. Excellent electrical insulation performance
   PTFE is a highly non-polar material with excellent dielectric properties; it has excellent arc resistance. During high-voltage discharge, it only releases some cracked non-conductive gas without carbonization and causing short circuit.
6. Excellent aging resistance and radiation resistance
   PTFE molecules do not have photosensitive groups, so they are not only dimensionally stable at low and high temperatures, but also have unchanged performance under harsh environments, are not attacked by microorganisms in humid conditions, and have extremely high protection against various radiation.
7. Extremely low water absorption
   PTFE’s water absorption is generally around 0.001% to 0.005%, and its permeability is also low.