Polytetrafluoroethylene is produced by free radical polymerization of tetrafluoroethylene. Industrial polymerization is carried out by stirring in the presence of a large amount of water to disperse the reaction heat and facilitate temperature control. Polymerization is generally carried out under the pressure of 40~80℃,3~26 kgs force/cm2. inorganic persulfate and organic peroxides can be used as initiator, or redox can be used to trigger the system. Heat release 171.38kJ per mole of tetrafluoroethylene polymerization. Dispersion polymerization requires the addition of perfluorotype surfactants, such as perfluorooctanoic acid or its salts.
Polytetrafluoroethylene can be compressed or extruded; It can also be made into water dispersion for coating, dipping or fiber making. Polytetrafluoroethylene is widely used as high and low temperature resistant and corrosion resistant materials and insulating materials in atomic energy, aerospace, electronics, electricity, chemical industry, machinery, instruments, meters, construction, textile, food and other industries, anti-sticking coating, etc.
Polytetrafluoroethylene is widely used in various kinds of anti-acid and organic solvents. It has no toxicity to human beings, but ammonium perfluorooctanoic acid (PFOA), one of the raw materials used in the production process, is considered to have carcinogenic effect.
Main function expanded polytetrafluoroethylene raw belt uses 100% polytetrafluoroethylene as raw material, which has a network expanded structure composed of fine long fibers and knots. Expanded Polytetrafluoroethylene raw material belt has the characteristics of good toughness, high longitudinal strength and easy lateral deformation. It is an ideal material for disc update and thread sealing. However, it cannot be used in contact with high concentration oxygen or liquid oxygen.