Teflon

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۱۶۴ انتشار • فعال از ۲۰۰۶

Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene, and has numerous applications because it is heat resistant and chemically inert. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off from DuPont, which originally invented the compound in 1938. Polytetrafluoroethylene is a fluorocarbon solid, as it is a high-molecular-weight polymer consisting wholly of carbon and fluorine. PTFE is hydrophobic: neither water nor water-containing substances wet PTFE, as fluorocarbons exhibit only small London dispersion forces due to the low electric polarizability of fluorine. PTFE has one of the lowest coefficients of friction of any solid. Polytetrafluoroethylene is used as a non-stick coating for pans and other cookware. It is non-reactive, partly because of the strength of carbon–fluorine bonds, so it is often used in containers and pipework for reactive and corrosive chemicals. When used as a lubricant, PTFE reduces friction, wear, and energy consumption of machinery. It is used as a coating on catheters, and, in its expanded porous form (ePTFE), as a graft material in surgery and as an implant in cardiac and vascular reconstruction, hernia repair, and facial plastic surgery. PTFE and chemicals used in its production are some of the best-known and widely applied per- and polyfluoroalkyl substances (PFAS), which are persistent organic pollutants. PTFE occupies more than half of all fluoropolymer production, followed by polyvinylidene fluoride (PVDF). For decades, DuPont used perfluorooctanoic acid (PFOA, or C8) during production of PTFE, later discontinuing its use due to legal actions over ecotoxicological and health effects of exposure to PFOA. DuPont's spin-off Chemours currently manufactures PTFE using an alternative chemical it calls GenX, another PFAS.