Polytetrafluoroethene (Polytetrafluoroethene), commonly known as "non-stick coating" or "easy cleaning radium material", is a synthetic polymer material that uses fluorine to replace all hydrogen atoms in polyethylene. This material has the characteristics of acid resistance, alkali resistance and resistance to various organic solvents, and is insoluble in almost all solvents. At the same time, polytetrafluoroethylene (PTFE) has the characteristics of high temperature resistance, its friction coefficient is very low, so it can be used as lubrication, but also become an ideal coating for easy cleaning radium and inner water pipe. The mechanical properties of PTFE are relatively soft. It has very low surface energy. 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 - aqua regia and all organic solvents; weather resistance - the best aging life of plastics; high lubrication - with the smallest friction coefficient of plastics (0.04); non-stickiness - with the smallest surface tension of solid materials. It does not adhere to any substance, is harmless - has physiological inertia, and has excellent electrical properties. It is an ideal class C insulating material. Polytetrafluoroethylene (PTFE) materials are widely used in defense industry, atomic energy, petroleum, radio, power machinery, chemical industry and other important sectors. Products: PTFE bars, pipes, sheets, turning sheets. Polytetrafluoroethylene is a polymer of tetrafluoroethylene. The English abbreviation is PTFE. The structural formula is uuuuuuuuuuuu It was discovered in the late 1930s that it was put into industrial production in the 1940s. The relative molecular weight of polytetrafluoroethylene (PTFE) is larger, the lower is hundreds of thousands, the higher is more than ten million, generally is millions (degree of polymerization is 104 orders of magnitude, while polyethylene is only 103). Generally, the crystallinity is 90-95%, and the melting temperature is 327-342 C. CF2 units in polytetrafluoroethylene molecule are arranged in zigzag shape. Because the radius of fluorine atoms is slightly larger than that of hydrogen, the adjacent CF2 units can not be completely trans-oriented, but form a spiral twisted chain. The fluorine atoms almost cover the surface of the whole polymer chain. This molecular structure explains the various properties of PTFE. 13/6 helix is formed when the temperature is lower than 19 C, and 15/7 helix is formed when the molecule is slightly decomposed at 19 C. Although carbon-carbon bonds and carbon-fluorine bonds in perfluorocarbons need to absorb energy 346.94 and 484.88 kJ/mol respectively, it only takes energy 171.38 kJ to produce 1 mol tetrafluoroethylene by depolymerization of polytetrafluoroethylene. Therefore, PTFE is mainly depolymerized into tetrafluoroethylene during pyrolysis at high temperature. The weightlessness rates (%) of PTFE at 260, 370 and 420 (%) were 1 *10-4, 4 *10-3 and 9 *10-2 per hour, respectively. It can be seen that PTFE can be used for a long time at 260 C. Due to the toxic by-products such as fluorophosgene and perfluoroisobutylene produced during pyrolysis at high temperature, special attention should be paid to safety protection and prevention of PTFE from exposure to open fire.