Polytetrafluoroethylene (Polytetrafluoroethene) generally referred to as "non-stick coating" or "easy clean wok material"; is a fluoro-substituted polyethylene used in all of the hydrogen atoms of synthetic polymer material. This material has acid-alkali resistance of various characteristics of organic solvents, almost insoluble in all solvents. At the same time, PTFE has high temperature characteristics, its low coefficient of friction, so that it can be used for more than a lubricant, has become an ideal coating easy to clean wok and inner pipes. PTFE Teflon ring physical properties: No. EINECS 204-126-9 CAS No.: 9002-84-0 Molecular formula: (C2F4) n Molecular Weight: 100.015612 Melting point: 327 ℃ Boiling point: 400 ℃ refractive index: 1.35 PTFE polytetrafluoroethylene ring fluoride chemical properties: resistance to atmospheric aging: radiation resistance and low permeability: long-term exposure to the atmosphere, surface and performance remained unchanged. Non-flammable: the limiting oxygen index of 90 or less. Acid resistance: insoluble in acids, alkalis and organic solvents (including magic acid, namely fluorine antimony sulfonic acid). Oxidation resistance: corrosion resistant and strong oxidants. PH: neutral. Advantages of high temperature PTFE ring - use operating temperature up to 250 ℃. Low temperature - with good mechanical toughness; even if the temperature drops to -196 ℃, but also to maintain a 5% elongation. Corrosion - for most chemicals and solvents, showing an inert, resistant to acid and alkali, water and various organic solvents. Weatherability - the best plastic aging life. High lubrication - is a solid material in the lowest coefficient of friction. Not adhere to - is a solid material in the minimum surface tension, does not adhere to any substance. Non-toxic - with physical inertia, as a long-term implantation of artificial blood vessels and organs of the body without adverse reaction. Larger molecular weight PTFE, hundreds of thousands of low and high of up to one million or more, generally millions (degree of polymerization of 104 orders of magnitude, while the polyethylene only 103). Degree of crystallinity is generally 90 to 95 percent, a melting temperature of 327 ~ 342 ℃. PTFE molecule CF2 unit arranged by zigzag shape, due to the fluorine atom radius larger than the hydrogen, so adjacent CF2 units can not cross exactly as trans orientation, but the formation of twisted chain, fluorine atom is almost covered with a spiral the entire surface of the polymer chain. This molecular structure explains the various properties of PTFE. When the temperature is below 19 ℃, the formation of 13/6 helix; phase transition at 19 ℃, molecular slightly untied, 15/7 spiral form.