Array ( [0] => {{short description|Synthetic polymer}} [1] => {{Redirect|Teflon}} [2] => {{Use dmy dates|date=September 2020}} [3] => [4] => '''Polytetrafluoroethylene''' ('''PTFE''') is a synthetic [[fluoropolymer]] of [[tetrafluoroethylene]], and has numerous applications because it is chemically inert. The commonly known brand name of PTFE-based composition is '''Teflon''' by [[Chemours]],{{cite web|last=|first=|date=|title=The History of Teflon Fluoropolymers|url=https://www.teflon.com:443/en/news-events/history|archive-url=|archive-date=|access-date=2021-02-03|website=Teflon.com|language=en}} a [[corporate spin-off|spin-off]] from [[DuPont (1802–2017)|DuPont]], which originally discovered the compound in 1938. [5] => {{chembox [6] => | Verifiedfields = changed [7] => | Watchedfields = changed [8] => | verifiedrevid = 477171888 [9] => | Name = [10] => | ImageFile = Polytetrafluoroethylene.svg [11] => | ImageSize = 130px [12] => | ImageFile1 = Perfluorodecyl-chain-from-xtal-Mercury-3D-balls.png [13] => | ImageSize1 = 350px [14] => | IUPACName = Poly(1,1,2,2-tetrafluoroethylene) [15] => {{cite web [16] => | url=http://www.ebi.ac.uk/chebi/searchId.do?chebiId=53251 [17] => | title=poly(tetrafluoroethylene) (CHEBI:53251) [18] => | access-date=12 July 2012 [19] => | work=ebi.ac.uk [20] => }} [21] => | SystematicName = [22] => | OtherNames = Fluon, Poly(tetrafluoroethene), Poly(difluoromethylene), Poly(tetrafluoroethylene), teflon [23] => | Section1 = {{Chembox Identifiers [24] => | Abbreviations = PTFE [25] => | ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}} [26] => | ChemSpiderID = None [27] => | CASNo_Ref = {{cascite|correct|CAS}} [28] => | UNII_Ref = {{fdacite|correct|FDA}} [29] => | UNII = E1NC1JVS3O [30] => | ChEBI_Ref = {{ebicite|changed|EBI}} [31] => | ChEBI = 53251 [32] => | PubChem = [33] => | CASNo = 9002-84-0 [34] => | KEGG_Ref = {{keggcite|changed|kegg}} [35] => | KEGG = D08974 [36] => }} [37] => | Section2 = {{Chembox Properties [38] => | Formula = (C2F4)n [39] => | Density = 2200{{nbsp}}kg/m3 [40] => | MeltingPt = 327 [[Celsius|°C]] [41] => | ThermalConductivity = 0.25 W/(m·K) [42] => | ElectricalResistivity = 1018 Ω·cm{{efn|Dielectric. Bulk resistivity.{{cite web |url=http://www.microwaves101.com/encyclopedia/PTFE.cfm |title=PTFE |work=Microwaves101 |access-date=16 February 2012 |archive-date=16 July 2014 |archive-url=https://web.archive.org/web/20140716201011/http://www.microwaves101.com/ENCYCLOPEDIA/PTFE.cfm |url-status=dead }}}} [43] => }} [44] => | Section3 = [45] => | Section4 = [46] => | Section5 = [47] => | Section6 = [48] => | Section7 = {{Chembox Hazards [49] => | NFPA-H = 1 [50] => | NFPA-F = 0 [51] => | NFPA-R = 0 [52] => | NFPA-S = OX [53] => }} [54] => }} [55] => [56] => 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 [[Wetting|wet]] PTFE, as fluorocarbons exhibit only small [[London dispersion force]]s due to the low [[polarizability|electric polarizability]] of fluorine. PTFE has one of the lowest coefficients of [[friction]] of any solid. [57] => [58] => 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 bond]]s, so it is often used in containers and pipework for reactive and corrosive chemicals. Where used as a [[lubricant]], PTFE reduces friction, wear, and energy consumption of machinery. It is used as a graft material in surgery and as a coating on [[catheter]]s. [59] => [60] => PTFE is one of the best-known and widely applied [[Per- and polyfluoroalkyl substances|PFAS]] commonly described as persistent organic pollutants or "forever chemicals". Only since the start of the 21st century has the environmental impact and toxicity to human and mammalian life been studied in depth. For decades, DuPont used [[perfluorooctanoic acid]] (PFOA, or C8) during production of PTFE, later discontinuing its use due to ecotoxicological and health issues that led to [[Perfluorooctanoic acid#Legal actions|legal actions]]. Dupont's spin-off Chemours today manufactures PTFE using an alternative chemical it calls [[GenX]], another PFAS. [61] => [62] => == History == [63] => [[File:Happy Pan Poster.jpg|left|thumb|upright|Advertisement of the Happy Pan, a Teflon-coated pan from the 1960s]]{{external media |width = 210px [https://www.sciencehistory.org/distillations/podcast/teflon "From stove tops to outer space... Teflon touches every one of us some way almost every day."], Roy Plunkett, [[Science History Institute]]}} [64] => [[File:1963 Zepel advertisement.jpg|thumb|upright|Advertisement for Zepel, the trade name used to market Teflon as a fabric treatment]] [65] => [[File:EL-1994-00019.jpeg|thumb|upright|PTFE thermal cover showing impact craters, from NASA's Ultra Heavy Cosmic Ray Experiment (UHCRE) on the [[Long Duration Exposure Facility]] (LDEF)]] [66] => [[File:Teflon logo.svg|thumb|Logo of Teflon, the commonly known brand name of PTFE-based compositions manufactured by Chemours]] [67] => [68] => Polytetrafluoroethylene (PTFE) was accidentally discovered in 1938 by [[Roy J. Plunkett]] while he was working in New Jersey for [[DuPont]]. As Plunkett attempted to make a new [[chlorofluorocarbon]] refrigerant, the [[tetrafluoroethylene]] gas in its pressure bottle stopped flowing before the bottle's weight had dropped to the point signaling "empty". Since Plunkett was measuring the amount of gas used by weighing the bottle, he became curious as to the source of the weight, and finally resorted to sawing the bottle apart. He found the bottle's interior coated with a waxy white material that was oddly slippery. Analysis showed that it was polymerized perfluoroethylene, with the iron from the inside of the container having acted as a catalyst at high pressure.{{cite web |title=Roy J. Plunkett |url=https://www.sciencehistory.org/historical-profile/roy-j-plunkett |website=Science History Institute |date=June 2016 |access-date=10 February 2020}} Kinetic Chemicals patented the new fluorinated plastic (analogous to the already known [[polyethylene]]) in 1941,{{Cite patent|inventor-last = Plunkett|inventor-first = Roy J|inventorlink = Roy Plunkett|issue-date = 4 February 1941|title = Tetrafluoroethylene polymers|country-code = US|patent-number = 2230654}} and registered the Teflon trademark in 1945.{{cite news|title = History Timeline 1930: The Fluorocarbon Boom|url= http://www2.dupont.com/Refrigerants/en_US/sales_support/history_1930.html|access-date =10 June 2009|publisher=DuPont}}{{cite news|title = Roy Plunkett: 1938|url = http://www2.dupont.com/Heritage/en_US/1938_dupont/1938_indepth.html|access-date = 10 June 2009|archive-date = 17 February 2012|archive-url = https://web.archive.org/web/20120217011800/http://www2.dupont.com/Heritage/en_US/1938_dupont/1938_indepth.html|url-status = dead}} [69] => [70] => By 1948, DuPont, which founded Kinetic Chemicals in partnership with [[General Motors]], was producing over {{convert|2,000,000|lb}} of Teflon-brand polytetrafluoroethylene per year in [[Parkersburg, West Virginia]].''[[American Heritage of Invention & Technology]]'', Fall 2010, vol. 25, no. 3, p. 42 An early use was in the [[Manhattan Project]] as a material to coat valves and seals in the pipes holding highly reactive [[uranium hexafluoride]] at the vast [[K-25]] [[enriched uranium|uranium enrichment]] plant in [[Oak Ridge, Tennessee]].{{Cite book |last=Rhodes |first=Richard |author-link=Richard Rhodes |title=The Making of the Atomic Bomb |publisher=Simon and Schuster |year=1986 |location=New York |page=494 |url=https://books.google.com/books?id=aSgFMMNQ6G4C |access-date=31 October 2010 |isbn=0-671-65719-4}} [71] => [72] => In 1954, Colette Grégoire urged her husband, the French engineer Marc Grégoire, to try the material he had been using on fishing tackle on her cooking pans. He subsequently created the first PTFE-coated, [[non-stick pans]] under the brand name [[Tefal]] (combining "Tef" from "Teflon" and "al" from aluminium).{{cite web|archive-date = 14 February 2008|website = Useless Information|url = http://home.nycap.rr.com/useless/teflon/index.html |archive-url=https://web.archive.org/web/20080214150646/http://home.nycap.rr.com/useless/teflon/index.html |title=Teflon |publisher=home.nycap.rr.com}} In the United States, [[Marion A. Trozzolo]], who had been using the substance on scientific utensils, marketed the first US-made PTFE-coated pan, "The Happy Pan", in 1961.Robbins, William (21 December 1986) "[https://www.nytimes.com/1986/12/21/us/teflon-maker-out-of-frying-pan-into-fame.html Teflon Maker: Out of Frying Pan into Fame ]", ''[[New York Times]]'', Retrieved 21 December 1986 (Subscription) Non-stick cookware has since become a common household product, now offered by hundreds of manufacturers across the world. [73] => [74] => The brand name Zepel was used for promoting its stain-resistance and water-resistance when applied to fabrics.{{cite news |last=Fenton |first=Lois |date=1992-01-02 |title=Go, spot, go Teflon enters fashion world as a protective coating |url=https://www.baltimoresun.com/news/bs-xpm-1992-01-02-1992002050-story.html |work=Baltimore Sun |archive-url=https://web.archive.org/web/20210620172022/https://www.baltimoresun.com/news/bs-xpm-1992-01-02-1992002050-story.html|archive-date=2021-06-20}} [75] => [76] => In the 1990s, it was found that PTFE could be radiation [[cross-linked]] above its melting point in an oxygen-free environment.{{cite journal|doi=10.1016/0969-806X(94)90226-7 |title=Modification of polytetrafluoroethylene by radiation—1. Improvement in high temperature properties and radiation stability|author= Sun, J.Z.|journal=Radiat. Phys. Chem. |year=1994|pages= 655–679|volume=44|issue=6|display-authors=etal|bibcode=1994RaPC...44..655S}} [[Electron beam processing]] is one example of radiation processing. Cross-linked PTFE has improved high-temperature mechanical properties and radiation stability. That was significant because, for many years, irradiation at ambient conditions has been used to break down PTFE for recycling.[http://www.e-beamservices.com/chain.htm Electron Beam Processing of PTFE] {{Webarchive|url=https://web.archive.org/web/20130906131658/http://e-beamservices.com/chain.htm |date=6 September 2013 }} E-BEAM Services website. Accessed 21 May 2013 This radiation-induced [[chain scission]] allows it to be more easily reground and reused. [77] => [78] => [[Corona treatment|Corona discharge treatment]] of the surface to increase the energy and improve adhesion has been reported.{{Cite web |title=Corona Discharge Treatment - an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/engineering/corona-discharge-treatment |access-date=2022-04-28 |website=www.sciencedirect.com}} [79] => [80] => == Production == [81] => PTFE is produced by [[free-radical]] [[polymerization]] of [[tetrafluoroethylene]].{{cite journal |last1=Puts |first1=Gerard J. |last2=Crouse |first2=Philip |last3=Ameduri |first3=Bruno M. |title=Polytetrafluoroethylene: Synthesis and Characterization of the Original Extreme Polymer |journal=Chemical Reviews |date=28 January 2019 |doi=10.1021/acs.chemrev.8b00458 |volume=119 |issue=3 |pages=1763–1805|pmid=30689365 |s2cid=59338589 |hdl=2263/68582 |hdl-access=free }} The net equation is [82] => : ''n'' F2C=CF2 → −(F2C−CF2)''n''− [83] => Because tetrafluoroethylene can explosively decompose to [[tetrafluoromethane]] (CF4) and carbon, a special apparatus is required for the polymerization to prevent hot spots that might initiate this dangerous side reaction. The process is typically initiated with [[Peroxydisulfate|persulfate]], which [[Homolysis (chemistry)|homolyzes]] to generate sulfate radicals: [84] => : [O3SO−OSO3]2− ⇌ 2 {{chem|SO|4|•−}} [85] => The resulting polymer is terminated with [[sulfate ester]] groups, which can be [[hydrolyzed]] to give OH [[end-group]]s.Carlson, D. Peter and Schmiegel, Walter (2000) "Fluoropolymers, Organic" in ''Ullmann's Encyclopedia of Industrial Chemistry'', Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a11_393}} [86] => [87] => Granular PTFE is produced via suspension polymerization, where PTFE is suspended in an aqueous medium primarily via agitation and sometimes with the use of a surfactant. PTFE is also synthesized via emulsion polymerization, where a surfactant is the primary means of keeping PTFE in an aqueous medium.{{cite book |chapter-url=https://www.sciencedirect.com/science/article/pii/B9781455774425000073 |doi=10.1016/B978-1-4557-7442-5.00007-3 |chapter=Manufacturing Polytetrafluoroethylene |title=Introduction to Fluoropolymers |year=2013 |pages=91–124 |publisher=William Andrew |isbn=9781455774425}} Surfactants in the past have included toxic [[perfluorooctanoic acid]] (PFOA) and [[perfluorooctanesulfonic acid]] (PFOS). More recently, Perfluoro 3,6 dioxaoctanoic acid (PFO2OA) and [[FRD-903]] (GenX) are being used as an alternative surfactants.{{cite journal |last1=Pierozan |first1=Paula |last2=Cattani |first2=Daiane |last3=Karlsson |first3=Oskar |title=Tumorigenic activity of alternative per- and polyfluoroalkyl substances (PFAS): Mechanistic in vitro studies |journal=Science of the Total Environment |date=February 2022 |volume=808 |pages=151945 |doi=10.1016/j.scitotenv.2021.151945 |pmid=34843762 |bibcode=2022ScTEn.808o1945P |s2cid=244730906 |doi-access=free }} [88] => [89] => == Properties == [90] => [[File:Blintzes in frying pan.jpg|thumb|right|PTFE is often used to coat [[non-stick pans]] as it is [[hydrophobic]] and possesses fairly high heat resistance.]] [91] => [92] => PTFE is a [[thermoplastic]] [[polymer]], which is a white solid at room temperature, with a density of about 2200 kg/m3 and a melting point of {{convert|600|K}}.{{cite web |title=Fluoroplastic Comparison - Typical Properties |url=https://www.chemours.com/Teflon_Industrial/en_US/tech_info/techinfo_compare.html |website=Chemours |archive-url= https://web.archive.org/web/20160203093128/https://www.chemours.com/Teflon_Industrial/en_US/tech_info/techinfo_compare.html |archive-date=3 February 2016 |url-status=dead}} It maintains high strength, toughness and self-lubrication at low temperatures down to {{convert|5|K}}, and good flexibility at temperatures above {{convert|194|K}}.[http://www.rjchase.com/ptfe_handbook.pdf Teflon PTFE Properties Handbook]. Retrieved 11 October 2012. PTFE gains its properties from the aggregate effect of [[carbon-fluorine bond]]s, as do all fluorocarbons. The only chemicals known to affect these carbon-fluorine bonds are highly reactive metals like the [[alkali metal]]s, at higher temperatures such metals as aluminium and magnesium, and fluorinating agents such as [[xenon difluoride]] and [[cobalt(III) fluoride]].{{cite web|url=https://plastechcoatings.com/chemours-teflon/|title= Chemours Teflon™ Coating Applications |website=plastechcoatings.com}} At temperatures above {{Convert|650|–|700|C|F|-1}} PTFE undergoes depolymerization.{{cite journal |author1=R. J. Hunadi |author2=K. Baum |title=Tetrafluoroethylene: A Convenient Laboratory Preparation |journal=Synthesis |year=1982 |volume=39 |issue=6 |page=454 |doi=10.1055/s-1982-29830|s2cid=96276938 }} [93] => [94] => {| class="wikitable" [95] => |- [96] => ! Property [97] => ! Value [98] => |- [99] => | [[Glass transition temperature|Glass temperature]] [100] => | {{Convert|114.85|C|F K}}{{cite book | title=The Chemistry of Polymers | publisher=Royal Society of Chemistry | author=Nicholson, John W. | year=2011 | page=50 | isbn=9781849733915 | url=https://books.google.com/books?id=5XFsT69cX_YC&q=polymer+chemistry | edition=4, Revised}} [101] => |- [102] => | [[Thermal expansion]] [103] => | 112–125×10−6 K−1{{cite web |url=http://www.engineershandbook.com/Tables/plasticthermalexp.htm |title=Reference Tables – Thermal Expansion Coefficients – Plastics |work=engineershandbook.com |access-date=2 January 2012 |archive-date=3 January 2012 |archive-url=https://web.archive.org/web/20120103183144/http://engineershandbook.com/Tables/plasticthermalexp.htm |url-status=dead }} [104] => |- [105] => | [[Thermal diffusivity]] [106] => | 0.124 mm{{sup|2}}/s{{cite journal |author1=Blumm, J. |author2=Lindemann, A. |author3=Meyer, M. |author4=Strasser, C. | title=Characterization of PTFE Using Advanced Thermal Analysis Technique |journal=[[International Journal of Thermophysics]]| volume=40 |issue=3–4 |page=311 | year=2011 |doi= 10.1007/s10765-008-0512-z |bibcode=2010IJT....31.1919B |s2cid=122020437 }} [107] => |- [108] => | [[Young's modulus]] [109] => | 0.5 GPa [110] => |- [111] => | [[Yield strength]] [112] => | 23 MPa [113] => |- [114] => | [[Coefficient of friction]] [115] => | 0.05–0.10 [116] => |- [117] => | [[Dielectric constant]] [118] => | {{nowrap|ε {{=}} 2.1}}, {{nowrap|[[dissipation factor|tan(δ)]] < 5×10{{sup|−2}}}} [119] => |- [120] => | Dielectric constant (60 Hz) [121] => | {{nowrap|ε {{=}} 2.1}}, {{nowrap|[[dissipation factor|tan(δ)]] < 2×10{{sup|−2}}}} [122] => |- [123] => | [[Dielectric strength]] (1 MHz) [124] => | 60 MV/m [125] => |- [126] => | [[Magnetic susceptibility]] (SI, 22 °C) [127] => | −10.28×10−6{{cite journal |last1=Wapler |first1=M. C. |last2=Leupold |first2=J. |last3=Dragonu |first3=I. |last4=von Elverfeldt |first4=D. |last5=Zaitsev |first5=M. |last6=Wallrabe |first6=U. |title=Magnetic properties of materials for MR engineering, micro-MR and beyond |journal=JMR |date=2014 |volume=242 |pages=233–242 |doi=10.1016/j.jmr.2014.02.005 |arxiv=1403.4760 |bibcode=2014JMagR.242..233W |pmid=24705364|s2cid=11545416 }} [128] => |} [129] => [130] => The [[coefficient of friction]] of plastics is usually measured against polished steel.[http://www.matweb.com/reference/coefficient-of-friction.asp Coefficient of Friction (COF) Testing of Plastics]. MatWeb Material Property Data. Retrieved 1 January 2007. PTFE's coefficient of friction is 0.05 to 0.10, which is the third-lowest of any known solid material ([[aluminium magnesium boride]] (BAM) being the first, with a coefficient of friction of 0.02; [[diamond-like carbon]] being second-lowest at 0.05). PTFE's resistance to [[van der Waals force]]s means that it is the only known surface to which a [[gecko]] cannot stick."[https://web.archive.org/web/20071014063923/http://socrates.berkeley.edu/~peattiea/research_main.html Research into Gecko Adhesion]", ''[[University of California, Berkeley|Berkeley]]'', 2007-10-14. Retrieved 8 April 2010. In addition, PTFE can be used to prevent insects from climbing up surfaces painted with the material. For example, PTFE is used to prevent ants from climbing out of [[formicarium|formicaria]]. [131] => [132] => Because of its chemical and thermal properties, PTFE is often used as a gasket material within industries that require resistance to aggressive chemicals such as pharmaceuticals or chemical processing.{{cite web |url=http://www.gasketresources.com/ptfe-gaskets |title=PTFE Sheet |website=Gasket Resources Inc. |access-date=2017-08-16}} However, until the 1990s, PTFE was not known to crosslink like an [[elastomer]], due to its chemical inertness. Therefore, it has no "memory" and is subject to [[creep (deformation)|creep]]. Because of the propensity to creep, the long-term performance of such seals is worse than for elastomers that exhibit zero, or near-zero, levels of creep. In critical applications, [[Belleville washer]]s are often used to apply continuous force to PTFE gaskets, thereby ensuring a minimal loss of performance over the lifetime of the gasket.{{cite web |url=http://www.sealing.com/fileadmin/docs/Using_Bellville_springs_to_maintain_bolt_preload.pdf |title=Using Belleville Springs To Maintain Bolt Preload |last=Davet |first=George P. |work=Solon Mfg. Co. |access-date=18 May 2014 |archive-date=18 May 2014 |archive-url=https://web.archive.org/web/20140518064415/http://www.sealing.com/fileadmin/docs/Using_Bellville_springs_to_maintain_bolt_preload.pdf |url-status=dead }} [133] => [134] => PTFE is an [[ultraviolet]] (UV) transparent polymer. However, when exposed to an [[excimer laser]] beam it severely degrades due to heterogeneous [[photothermal effect]].{{Cite journal |last1=Ferry |first1=Laurent |last2=Gérard |first2=Vigier |last3=Bessede |first3=Jean Luc |date=June 1996 |title=Effect of ultraviolet radiation on polytetrafluoroethylene: Morphology influence |url=https://onlinelibrary.wiley.com/doi/10.1002/(SICI)1099-1581(199605)7:5/6%3C493::AID-PAT536%3E3.0.CO;2-D |journal=Polymers for Advanced Technologies |volume=7 |issue=5–6 |pages=493–500 |doi=10.1002/(SICI)1099-1581(199605)7:5/6<493::AID-PAT536>3.0.CO;2-D |via=Wiley}} [135] => [136] => == Processing == [137] => Processing PTFE can be difficult and expensive, because the high melting temperature, {{convert|327|C}}, is above the initial decomposition temperature, {{convert|200|C}}. Even when molten, PTFE does not flow due to its exceedingly high melt-viscosity.{{cite web|url=http://www.cowie.com/thermal.htm|title=Cowie Technology – PTFE: High Thermal Stability|website=Cowie.com|access-date=2017-08-16}}{{cite web|url=http://www.inoflon.com/pdf/PG_Free%20flow%20granular%20PTFE.pdf|title=Free Flow Granular PTFE|date=2017-08-16|website=Inoflon Fluoropolymers}} The viscosity and melting point can be decreased by inclusion of small amount of [[comonomer]]s such as perfluoro (propylvinyl ether) and [[hexafluoropropylene]] (HFP). These cause the otherwise perfectly linear PTFE chain to become branched, reducing its crystallinity.{{cite book|author=Sina Ebnesajjad|title=Expanded PTFE Applications Handbook: Technology, Manufacturing and Applications|url=https://books.google.com/books?id=2veWaYOQ2ikC&pg=PP1|date=21 September 2016|publisher=William Andrew|isbn=978-1-4377-7856-4|pages=31–32}} [138] => [139] => Some PTFE parts are made by cold-moulding, a form of [[compression molding]].{{cite web|url=http://www.daikinchem.de/downloads/PTFE-M.pdf|title=Polyflon PTFE Molding Powder|date=2017-08-16|website=Daikin Chemical}} Here, fine powdered PTFE is forced into a mould under high pressure (10–100 MPa). After a settling period, lasting from minutes to days, the mould is heated at {{convert|360 to 380|C}}, allowing the fine particles to fuse ([[sintering|sinter]]) into a single mass.{{cite web |title=Unraveling Polymers: PTFE |publisher=Poly Fouoro Ltd. |date=26 April 2011 |url=http://polyfluoroltd.blogspot.com/2011/04/ptfe-myths-busted.html |access-date=23 April 2017}} [140] => [141] => == Applications and uses == [142] => {{more citations needed section|date=May 2017}} [143] => [[File:Gore twisted pair cable, Passenger Experience Week 2018, Hamburg (1X7A3731) (cropped).jpg|thumb|upright|PTFE-jacketed (white) shielded [[twisted-pair cable]]s]] [144] => [145] => === Wire insulation, electronics === [146] => The major application of PTFE, consuming about 50% of production,{{Cite web |title=Polytetrafluoroethylene - Introduction, Production, Applications, and FAQs |url=https://www.vedantu.com/chemistry/polytetrafluoroethylene |access-date=2024-04-01 |website=VEDANTU |language=en}} is for the insulation of wiring in aerospace and computer applications (e.g. hookup wire, coaxial cables).{{Cite web |last=Sack |first=Harald |date=2022-06-26 |title=Roy J. Plunkett and the Discovery of Teflon {{!}} SciHi Blog |url=http://scihi.org/roy-j-plunkett-teflon/ |access-date=2024-04-01 |language=en-US}} This application exploits the fact that PTFE has excellent [[dielectric]] properties, specifically low [[group velocity dispersion]],{{cite book |title=Handbook of Vinyl Polymers: Radical Polymerization, Process, and Technology, Second Edition |edition=2nd, illustrated, revised |first1=Munmaya |last1=Mishra |first2=Yusuf |last2=Yagci |publisher=CRC Press |year=208 |isbn=978-0-8247-2595-2 |page=574 |url=https://books.google.com/books?id=CoFE-itPBPgC}} [https://books.google.com/books?id=CoFE-itPBPgC&pg=PA574 Extract of page 574] especially at high [[radio frequency|radio frequencies]], making it suitable for use as an excellent [[Electrical insulation|insulator]] in [[electrical connector|connector]] assemblies and [[Electrical cable|cable]]s, and in [[printed circuit board]]s used at [[microwave]] frequencies. Combined with its high melting temperature, this makes it the material of choice as a high-performance substitute for the weaker, higher dispersion and lower-melting-point [[polyethylene]] commonly used in low-cost applications. [147] => [148] => === Bearings seals === [149] => In industrial applications, owing to its low friction, PTFE is used for [[plain bearing]]s, [[gear]]s, [[slide plate]]s, seals, gaskets, bushings,{{cite web|url=https://www.espemfg.com/teflon-machining-fabrication.html|title=Teflon Machining & Fabrication |website=Espemfg.com|access-date=2018-08-28}} and more applications with sliding action of parts, where it outperforms [[polyoxymethylene|acetal]] and [[nylon]].Mishra & Yagci, [https://books.google.com/books?id=CoFE-itPBPgC&pg=PA573 p 573] [150] => [151] => === Electrets === [152] => Its extremely high bulk [[resistivity]] makes it an ideal material for fabricating long-life [[electret]]s, the [[electrostatic]] analogues of [[magnet|permanent magnets]]. [153] => [154] => === Composites === [155] => PTFE film is also widely used in the production of carbon fiber composites as well as fiberglass composites, notably in the aerospace industry. PTFE film is used as a barrier between the carbon or fiberglass part being built, and breather and bagging materials used to incapsulate the bondment when debulking (vacuum removal of air from between layers of laid-up plies of material) and when curing the composite, usually in an autoclave. The PTFE, used here as a film, prevents the non-production materials from sticking to the part being built, which is sticky due to the carbon-graphite or fiberglass plies being pre-pregnated with [[bismaleimide]] resin. Non-production materials such as Teflon, Airweave Breather and the bag itself would be considered F.O.D. (foreign object debris/damage) if left in layup. [156] => [157] => [[Gore-Tex]] is a brand of expanded PTFE (ePTFE), a material incorporating a fluoropolymer membrane with micropores. The roof of the [[Hubert H. Humphrey Metrodome]] in [[Minneapolis]], US, was one of the largest applications of PTFE coatings. {{convert|20|acre|m2}} of the material was used in the creation of the white double-layered PTFE-coated fiberglass dome. [158] => [159] => === Chemically inert liners === [160] => Because of its extreme non-reactivity and high temperature rating, PTFE is often used as the liner in [[hose]] assemblies, [[expansion joint#Pipe expansion joints|expansion joint]]s, and in industrial pipe lines, particularly in applications using acids, alkalis, or other chemicals. Its frictionless qualities allow improved flow of highly viscous liquids, and for uses in applications such as brake hoses. [161] => [162] => === Tensioned membrane structures === [163] => PTFE architectural membranes are created by coating a woven glass-fibre base cloth with PTFE, forming one of the strongest and most durable materials used in [[tensile structure]]s.{{Cite web |title=PTFE |url=https://www.makmax.com.au/fabrics/ptfe/ |website=MakMax Australia}} Some notable structures featuring PTFE-tensioned membranes include [[The O2 Arena]] in London, [[Moses Mabhida Stadium]] in South Africa, [[Metropolitano Stadium]] in Spain and the [https://www.makmax.com.au/project/sydney-football-stadium-roof/ Sydney Football Stadium Roof] in Australia. [164] => [165] => === Musical instruments === [166] => PTFE is often found in musical instrument lubrication products; most commonly, valve oil. [167] => [168] => === Lubricants === [169] => PTFE is used in some aerosol lubricant sprays, including in micronized and polarized form. It is notable for its extremely low coefficient of friction, its hydrophobia (which serves to inhibit rust), and for the dry film it forms after application, which allows it to resist collecting particles that might otherwise form an abrasive paste.{{Cite news|url=https://interflonusa.com/what-is-micpol/#assembly|title=What is MicPol?|website=Interflonusa.com|access-date=2018-10-03|language=en|archive-date=3 October 2018|archive-url=https://web.archive.org/web/20181003141443/https://interflonusa.com/what-is-micpol/#assembly|url-status=dead}} Brands include GT85.{{Cite web|url=https://www.baysidemarine.co.uk/gt85-general-lubricant-with-ptfe---400ml-6284-p.asp|title=GT85 General Lubricant with PTFE - 400ml|website=Baysidemarine.co.uk|access-date=5 March 2022}} [170] => [[File:Teflon-jar hg.jpg|alt=Two teflon jars|thumb|Two PTFE jars{{clarify|reason=Are they coated (as mentioned in text) or fully PTFE from a mold? Is cold-molding used?|date=December 2021}}]] [171] => [172] => === Kitchen ware === [173] => PTFE is best known for its use in coating non-stick [[frying pan]]s and other cookware, as it is [[hydrophobic]] and possesses fairly high heat resistance. [174] => [175] => The sole plates of some clothes irons are coated with PTFE.[http://pratique.leparisien.fr/fiches-pratiques/electromenager/repassage/fers-a-repasser-semelle-teflon-1600004600043011#xtref=https%253A%252F%252Fwww.google.fr%252F Fers à repasser semelle teflon - Fiche pratique - Le Parisien]. Pratique.leparisien.fr. Retrieved on 2016-11-17. [176] => [177] => === Others === [178] => {{trivia|section|date=August 2023}} [179] => [[File:PTFE tapes with pressure-sensitive adhesive backing, rolls of 15 and 25 mm widths.jpg|thumb|right|PTFE tapes with pressure-sensitive adhesive backing]]Other niche applications include: [180] => * It is often found in [[ski binding]]s as a non-mechanical AFD (anti-friction device) [181] => * It can be stretched to contain small pores of varying sizes and is then placed between fabric layers to make a waterproof, breathable fabric in outdoor apparel.{{cite web|url=https://www.infinitymotorcycles.com/news/a-motorcyclists-guide-to-gore-tex/119|title=A Motorcyclist's Guide To Gore-Tex|publisher=Infinity Motorcycles|access-date=17 January 2019|archive-url=https://web.archive.org/web/20150705134857/https://www.infinitymotorcycles.com/news/a-motorcyclists-guide-to-gore-tex/119|archive-date=5 July 2015|url-status=dead}} [182] => * It is used widely as a fabric protector to repel stains on formal school-wear, like uniform blazers.{{cite web|url=http://www.cutterandtailor.com/forum/index.php?showtopic=852|title=Advantages and Disadvantages of Teflon-coated Covert Cloth|work=The Cutter and Tailor|access-date=22 May 2015|archive-date=3 July 2015|archive-url=https://web.archive.org/web/20150703221827/http://www.cutterandtailor.com/forum/index.php?showtopic=852|url-status=dead}} [183] => * It is frequently used as a lubricant to prevent captive insects and other [[arthropod]]s from escaping. [184] => * It is used as a coating for medical and healthcare applications formulated to provide strength and heat resistance to surgical devices and other medical equipment.{{Cite web|url=https://www.deltacoatingsandliningsbr.com/ptfe|title=PTFE & Industrial Non-Stick Fluoropolymer Coating Services | Delta Coatings & Linings, Inc.|website=Deltacoatingsandliningsbr.com|access-date=5 March 2022}} [185] => * It is used as a film interface patch for sports and medical applications, featuring a pressure-sensitive adhesive backing, which is installed in strategic high friction areas of footwear, insoles, [[ankle-foot orthosis]], and other medical devices to prevent and relieve friction-induced blisters, calluses and foot ulceration.{{cite web |url=http://www.oandp.org/jpo/library/popup.asp?xmlpage=2006_04_093&type=image&id=f11 |title=Film Interface Patch |publisher=American Academy of Orthotists & Prosthetists}} [186] => * Expanded PTFE membranes have been used in trials to assist [[trabeculectomy]] surgery to treat glaucoma.{{Cite journal |last1=Park |first1=Junghyun |last2=Rittiphairoj |first2=Thanitsara |last3=Wang |first3=Xue |last4=E |first4=Jian-Yu |last5=Bicket |first5=Amanda K. |date=2023-03-13 |title=Device-modified trabeculectomy for glaucoma |url= |journal=The Cochrane Database of Systematic Reviews |volume=2023 |issue=3 |pages=CD010472 |doi=10.1002/14651858.CD010472.pub3 |issn=1469-493X |pmc=10010250 |pmid=36912740 }} [187] => * Powdered PTFE is used in [[pyrotechnic composition]]s as an [[oxidizer]] with powdered metals such as [[aluminium]] and [[magnesium]]. Upon ignition, these mixtures form carbonaceous [[soot]] and the corresponding metal [[fluoride]], and release large amounts of heat. They are used in [[infrared decoy flare]]s and as [[igniter]]s for [[solid-fuel rocket]] [[propellant]]s.{{cite journal|author=Koch, E.-C. |title=Metal-Fluorocarbon Pyrolants:III. Development and Application of Magnesium/Teflon/Viton|journal=[[Propellants, Explosives, Pyrotechnics]] |year=2002|volume=27|pages=262–266|doi=10.1002/1521-4087(200211)27:5<262::AID-PREP262>3.0.CO;2-8| issue=5}} Aluminium and PTFE is also used in some [[thermobaric]] fuel compositions. [188] => * Powdered PTFE is used in a suspension with a low-viscosity, azeotropic mixture of siloxane ethers to create a lubricant for use in [[twisty puzzle]]s.{{cite web|url=https://thecubicle.us/lubicle-p-9146.html|title=Lubicle 1|website=TheCubicle.us|language=en|access-date=2017-05-20}} [189] => * In optical [[radiometry]], sheets of PTFE are used as measuring heads in spectroradiometers and broadband radiometers (e.g., [[illuminance]] meters and [[Ultraviolet|UV]] [[radiometer]]s) due to PTFE's capability to diffuse a transmitting light nearly perfectly. Moreover, optical properties of PTFE stay constant over a wide range of wavelengths, from UV down to near [[infrared]]. In this region, the ratio of its regular transmittance to diffuse transmittance is negligibly small, so light transmitted through a [[diffuser (optics)|diffuser]] (PTFE sheet) radiates like [[Lambert's cosine law]]. Thus PTFE enables cosinusoidal angular response for a detector measuring the power of optical radiation at a surface, e.g. in solar [[irradiance]] measurements. [190] => * [[Teflon-coated bullet]]s are coated with PTFE to reduce wear on the [[rifling]] of firearms that uncoated projectiles would cause. PTFE itself does not give a projectile an armor-piercing property.{{cite journal|url=http://www.guncite.com/ktwint.html|title=Interview with an inventor of the KTW bullet|journal=NRAction Newsletter|volume =4|issue =5 |date=May 1990}} [191] => * Its high corrosion resistance makes PTFE useful in laboratory environments, where it is used for lining containers, as a coating for magnetic stirrers, and as tubing for highly corrosive chemicals such as [[hydrofluoric acid]], which will dissolve glass containers. It is used in containers for storing [[fluoroantimonic acid]], a [[superacid]].{{cite web |url=http://www.realclearscience.com/blog/2013/08/the-worlds-strongest-acids.html |title=The World's Strongest Acids: Like Fire and Ice |last=Pomeroy |first=Ross |date=2013-08-24 |access-date=2016-04-09 }} [192] => * PTFE tubes are used in gas-gas heat exchangers in gas cleaning of waste incinerators. Unit power capacity is typically several megawatts. [193] => * PTFE is widely used as a [[thread seal tape]] in plumbing applications, largely replacing paste thread dope. [194] => * PTFE membrane filters are among the most efficient industrial air filters. PTFE-coated filters are often used in [[dust collection system]]s to collect [[aerosol|particulate matter]] from air streams in applications involving high temperatures and high particulate loads such as coal-fired power plants, cement production and steel foundries.{{cite web|url=http://www.baghouse.com/2012/05/28/industrial-air-permits-new-clean-air-regulations-and-baghouses/|title=Industrial Air Permits - New Clean Air Regulations And Baghouses|date=28 May 2012|publisher=Baghouse.com}} [195] => * PTFE grafts can be used to bypass [[stenosis|stenotic]] [[artery|arteries]] in peripheral vascular disease if a suitable autologous [[vein]] graft is not available. [196] => * Many bicycle lubricants and greases contain PTFE and are used on [[bicycle chain|chains]] and other moving parts subjected to frictional forces (such as [[Bicycle wheel#Bearings|hub bearings]]). [197] => * PTFE is used for some types of [[dental floss]]. [198] => * PTFE can also be used when placing [[dental fillings]], to isolate the contacts of the adjacent tooth so the restorative materials will not stick to the adjacent tooth.{{cite journal|url=http://www.dentistrytoday.com/restorative-134/1864--sp-1460991174|title=Using Plumber's Teflon Tape to Enhance Bonding Procedures|first=Dennis E. | last=Brown, DDS|journal=Dentistry Today|date=January 2002 |volume=21 |issue=1 |pages=76–8, 80–1 |pmid=11824121 }}{{cite journal|title=Polytetrafluoroethylene (PTFE) tape as a matrix in operative dentistry.|last=Dunn|first=WJ|display-authors=etal|journal=Operative Dentistry|pmid=15279489|volume=29|pages=470–2|year=2004|issue=4}} [199] => * PTFE sheets are used in the production of [[butane hash oil]] due to its non-stick properties and resistance to non-polar solvents.{{cite book |title=Beyond Buds |first=Ed |last=Rosenthal |publisher=Quick American Archives |edition=Revised |date=21 October 2014 |isbn=978-1936807239}} [200] => * PTFE, associated with a slightly textured laminate, makes the plain bearing system of a [[Dobsonian telescope]]. [201] => * PTFE is widely used as a non-stick coating for food processing equipment; dough hoppers, mixing bowls, conveyor systems, rollers, and chutes. PTFE can also be reinforced where abrasion is present – for equipment processing seeded or grainy dough for example.{{Cite news|url=http://www.surfacetechnology.co.uk/surface-coatings/fluoropolymer-coating/ |title= Fluoropolymer PTFE coating services from Surface Technology UK|work=Surface Technology|access-date=2018-02-26|language=en-US}} [202] => * PTFE has been experimented with for [[electroless nickel plating]]. [203] => * PTFE tubing is used for Bowden tubing in [[3D printing|3D printers]] because its low friction allows the extruder stepper motor to push filament through it more easily. [204] => * PTFE is commonly used in aftermarket add-on mouse feet for [[gaming mice]] to reduce friction of the mouse against the mouse pad, resulting in a smoother glide. [205] => * PTFE foils are commonly used with laserprinters everywhere, in their fuser unit, wrapped around the heater element(s) and as well on the opposite pressure roller to prevent any kind of sticking to it (neither the printed paper nor toner waste) [206] => * PTFE is also used to make body jewellery as it's much safer to wear compared to materials like acrylic, that release toxics into the body at 26.6 °C, unlike PTFE at 650–700 °C. [207] => * PTFE is used to make bookbinding tools for folding, scoring and separating sheets of paper. These are typically referred to as Teflon bone folders. [208] => * PTFE is commonly used for the tip of [[Desoldering#Pumps|desoldering pumps]] due to its high melting temperature. [209] => [210] => == Safety == [211] => While PTFE is stable at lower temperatures, it begins to deteriorate at temperatures of about {{convert|260|C}}, it decomposes above {{convert|350|C}}, and [[pyrolysis]] occurs at temperatures above {{Convert|400|C|F|abbr=on}}.{{Cite journal|last1=Sajid|first1=Muhammad|last2=Ilyas|first2=Muhammad|date=October 2017|title=PTFE-coated non-stick cookware and toxicity concerns: a perspective|url=http://link.springer.com/10.1007/s11356-017-0095-y|journal=Environmental Science and Pollution Research|language=en|volume=24|issue=30|pages=23436–23440|doi=10.1007/s11356-017-0095-y|pmid=28913736|bibcode=2017ESPR...2423436S |s2cid=10437300|issn=0944-1344}} The main decomposition products are [[fluorocarbon]] gases and a [[Sublimation (phase transition)|sublimate]], including [[tetrafluoroethylene]] (TFE) and [[difluorocarbene]] [[Radical (chemistry)|radicals]] (RCF2). [212] => [213] => An animal study conducted in 1955 concluded that it is unlikely that these products would be generated in amounts significant to health at temperatures below {{convert|250|C}}.{{cite journal |vauthors=Zapp JA, Limperos G, Brinker KC |title= Toxicity of pyrolysis products of 'Teflon' tetrafluoroethylene resin |journal= Proceedings of the American Industrial Hygiene Association Annual Meeting |date=26 April 1955}} Above those temperatures the degradation by-products can be lethal to [[bird]]s,{{cite news|publisher=DuPont|title=Key Safety Questions About Teflon Nonstick Coatings|url=http://www2.dupont.com/Teflon/en_US/products/safety/key_questions.html#q6|access-date=28 November 2014|archive-date=2 May 2013|archive-url=https://web.archive.org/web/20130502210638/http://www2.dupont.com/Teflon/en_US/products/safety/key_questions.html#q6|url-status=dead}} and can cause [[flu-like symptoms]] in humans ([[polymer fume fever]]),{{cite web|publisher=DuPont|url=http://www2.dupont.com/Teflon/en_US/products/safety/key_questions.html#q5|title=Key Safety Questions about the Safety of Nonstick Cookware|access-date=28 November 2014|archive-date=2 May 2013|archive-url=https://web.archive.org/web/20130502210638/http://www2.dupont.com/Teflon/en_US/products/safety/key_questions.html#q5|url-status=dead}} although in humans those symptoms disappear within a day or two of being moved to fresh air. [214] => [215] => Most cases of polymer fume fever in humans occur due to smoking PTFE-contaminated tobacco, although cases have occurred in people who have [[welding|welded]] near PTFE components. PTFE-coated cookware is unlikely to reach dangerous temperatures with normal use, as meat is usually fried between {{convert|204 and 232|C}}, and most [[cooking oil]]s (except refined [[safflower oil|safflower]] and [[avocado oil|avocado]] oils) start to [[smoke point|smoke]] before a temperature of {{convert|260|C|F}} is reached. A 1973 study by DuPont's Haskell Laboratory found that a 4-hour exposure to the fumes emitted by PTFE cookware heated to {{convert|280|C}} was lethal for [[parakeets]], although that was a higher temperature than the {{convert|260|C|F}} required for fumes from pyrolyzed butter to be lethal to the birds.{{cite journal |last1=Griffith |first1=Franklin D. |last2=Stephens |first2=Susan S. |last3=Tayfun |first3=Figen O. |title=Exposure of Japanese Quail and Parakeets to the Pyrolysis Products of Fry Pans Coated with Teflon® and Common Cooking Oils |journal=American Industrial Hygiene Association Journal |date=April 1973 |volume=34 |issue=4 |pages=176–178 |doi=10.1080/0002889738506828|pmid=4723395 }} [216] => [217] => [[Perfluorooctanoic acid]] (PFOA), a chemical formerly used in the manufacture of PTFE products such as non-stick coated cookware, can be [[carcinogen]]ic for people who are exposed to it (see [[#Ecotoxicity|Ecotoxicity]]).{{cite web |title=Perfluorooctanoic Acid (PFOA), Teflon, and Related Chemicals |url=https://www.cancer.org/cancer/cancer-causes/teflon-and-perfluorooctanoic-acid-pfoa.html |website=www.cancer.org |access-date=4 April 2022 |language=en}} Concerning levels of PFOA have been found in the blood of people who work in or live near factories where the chemical is used, and in people regularly exposed to PFOA-containing products such as some [[ski wax]]es and stain-resistant fabric coatings, but non-stick cookware was not found to be a major source of exposure, as the PFOA is burned off during the manufacturing process and not present in the finished product. Non-stick coated cookware has not been manufactured using PFOA since 2013,{{cite web|title=The truth about teflon: are non-stick pans safe?|url=https://www.bhg.com.au/the-truth-about-teflon-are-non-stick-pans-safe|access-date=2020-06-11|website=Better Homes and Gardens|date=2 October 2019 |language=en-us}} and PFOA is no longer being made in the United States. [218] => [219] => == Ecotoxicity == [220] => === Trifluoroacetate === [221] => [[Sodium trifluoroacetate]] and the similar compound chlorodifluoroacetate can both be generated when PTFE undergoes [[Thermal decomposition|thermolysis]], as well as producing longer chain polyfluoro- and/or polychlorofluoro- (C3-C14) carboxylic acids which may be equally persistent. These products can accumulate in evaporative [[wetland]]s and have been found in the roots and seeds of wetland plant species, but has not been observed to have an adverse impact on plant health or germination success.{{cite web |title=Hazardous Substances Data Bank (HSDB) : 833 |url=https://pubchem.ncbi.nlm.nih.gov/source/hsdb/833 |website=pubchem.ncbi.nlm.nih.gov |publisher=National Center for Biotechnology Information National Library of Medicine |access-date=4 April 2022 |language=en}} [222] => [223] => === PFOA === [224] => {{Main|Perfluorooctanoic acid}} [225] => Perfluorooctanoic acid (PFOA, or C8) has been used as a [[surfactant]] in the [[emulsion polymerization]] of PTFE, although several manufacturers have entirely discontinued its use. [226] => [227] => PFOA persists indefinitely in the environment.{{cite report|date = March 2014|title = Emerging Contaminants Fact Sheet – Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA) |url = https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100LTG6.txt|website = National Service Center for Environmental Publications|publisher = [[United States Environmental Protection Agency]] |id = 505-F-14-001 |access-date = 10 February 2019|page = 1}} PFOA has been detected in the blood of many individuals of the general US population in the low and sub-[[parts per billion]] range, and levels are higher in chemical plant employees and surrounding subpopulations. PFOA and [[perfluorooctanesulfonic acid]] (PFOS) have been estimated to be in every American person's blood stream in the parts per billion range, though those concentrations have decreased by 70% for PFOA and 84% for PFOS between 1999 and 2014, which coincides with the end of the production and phase out of PFOA and PFOS in the US.{{cite web|url=https://casaweb.org/wp-content/uploads/2020/01/National-PFAS-Receivers-Factsheet.pdf|title=PFAs Factsheet|website=Casaweb.org|access-date=5 March 2022}} The general population has been exposed to PFOA through massive dumping of C8 waste into the ocean and near the [[Ohio River]] Valley.{{cite news|last1=RIch|first1=Nathaniel |title= The Lawyer Who Became Dupont's Worst Nightmare|url=https://www.nytimes.com/2016/01/10/magazine/the-lawyer-who-became-duponts-worst-nightmare.html|newspaper=The New York Times|date=6 January 2016 |access-date=7 January 2016}}{{cite web|last1=Blake|first1=Mariah|title=Welcome to Beautiful Parkersburg, West Virginia Home to one of the most brazen, deadly corporate gambits in U.S. history.|url=http://highline.huffingtonpost.com/articles/en/welcome-to-beautiful-parkersburg/|website=HuffPost|access-date=31 August 2015}}{{cite news |last1=Fellner |first1=Carrie |title=Toxic Secrets: Professor 'bragged about burying bad science' on 3M chemicals |url=https://www.smh.com.au/lifestyle/health-and-wellness/toxic-secrets-professor-bragged-about-burying-bad-science-on-3m-chemicals-20180615-p4zlsc.html |access-date=25 June 2018 |work=[[The Sydney Morning Herald]]|date=16 June 2018}} PFOA has been detected in industrial waste, stain-resistant carpets, carpet cleaning liquids, [[house dust]], [[Popcorn bag|microwave popcorn bags]], water, food and PTFE cookware. [228] => [229] => As a result of [[Perfluorooctanoic acid#Robert Bilott investigation|a class-action lawsuit and community settlement]] with [[DuPont]], three [[Epidemiology|epidemiologists]] conducted studies on the population of Parkersburg, WV surrounding the (former DuPont) Chemours Washington Works chemical plant that was exposed to PFOA at levels greater than in the general population. The studies concluded that there was an association between PFOA exposure and six health outcomes: kidney cancer, testicular cancer, [[ulcerative colitis]], thyroid disease, [[hypercholesterolemia]] (high cholesterol), and pregnancy-induced hypertension.{{Cite journal | last1 = Nicole | first1 = W. | title = PFOA and Cancer in a Highly Exposed Community: New Findings from the C8 Science Panel | doi = 10.1289/ehp.121-A340 | journal = Environmental Health Perspectives | volume = 121 | issue = 11–12 | pages = A340 | year = 2013 | pmid = 24284021| pmc = 3855507}} [230] => [231] => Overall, PTFE cookware is considered a minor exposure pathway to PFOA.{{cite journal [232] => |vauthors=Trudel D, Horowitz L, Wormuth M, Scheringer M, Cousins IT, Hungerbühler K | title=Estimating consumer exposure to PFOS and PFOA [233] => | journal=Risk Anal. [234] => | volume=28 |issue=2 |pages=251–69 |date=April 2008 [235] => | pmid=18419647 |doi=10.1111/j.1539-6924.2008.01017.x| bibcode=2008RiskA..28..251T [236] => | s2cid=10777081 [237] => }} [238] => [239] => === GenX === [240] => {{Main|GenX}} [241] => As a result of the lawsuits concerning [[Perfluorooctanoic acid#Robert Bilott investigation|the PFOA class-action lawsuit]], DuPont began to use GenX, a similarly fluorinated compound, as a replacement for perfluorooctanoic acid in the manufacture of [[fluoropolymer]]s, such as Teflon-brand PTFE.{{cite web |title=Evaluation of substances used in the GenX technology by Chemours, Dordrecht |url=http://www.rivm.nl/dsresource?objectid=3186e480-7d66-4ded-ac59-acd2e804d3b5|date=2016-12-12 |last1=Beekman |first1=M. |last2=Zweers |first2=P. |display-authors=1|access-date=2017-07-23 |publisher=National Institute for Public Health and the Environment ([[RIVM]], The Netherlands)}}{{cite web |url=https://www.epa.gov/pfas/basic-information-pfas#difference |title=What is the difference between PFOA, PFOS and GenX and other replacement PFAS? |author= |date=2018-02-18 |website=PFOA, PFOS and Other PFASs |publisher=EPA}} However, in lab tests on rats, GenX has been shown to cause many of the same health problems as PFOA.{{cite journal |last1=Caverly Rae |first1=JM |last2=Craig |first2=Lisa |last3=Stone |first3=Theodore W. |last4=Frame |first4=Steven R. |last5=Buxton |first5=L. William |last6=Kennedy |first6=Gerald L. |title=Evaluation of chronic toxicity and carcinogenicity of ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate in Sprague–Dawley rats |date=2015 |journal=Toxicology Reports |volume=2 |pages=939–949 |doi=10.1016/j.toxrep.2015.06.001|pmc=5598527 |pmid=28962433 }}{{cite web|url=https://theintercept.com/2016/03/03/new-teflon-toxin-causes-cancer-in-lab-animals/|title=New Teflon Toxin Causes Cancer in Lab Animals|last=Lerner|first=Sharon|date=2016-03-03|website=The Intercept|language=en-US|access-date=2018-12-14}} [242] => [243] => The chemicals are manufactured by [[Chemours]], a corporate spin-off of DuPont, in [[Fayetteville, North Carolina]].{{cite web |url=https://files.nc.gov/ncdeq/GenX/SAB/FAQ_updated_021518.pdf |title=GenX Frequently Asked Questions |author= |date=2018-02-15 |website=GenX Investigation |publisher=North Carolina Department of Environmental Quality (NCDEQ) |location=Raleigh, NC}} Fayetteville Works was the site where DuPont began manufacture of PFOA after the lawsuit in Parkersburg WV halted their production there. When EPA asked companies to voluntarily phase out PFOA production, it was replaced by GenX in Fayetteville Works. In June of 2017, The Wilmington Star-News broke the storyhttps://www.starnewsonline.com/story/news/environment/2017/06/07/toxin-taints-cfpua-drinking-water/20684831007/ that GenX was found in the Cape Fear River – the drinking water supply for 500,000 people. The source of the pollution was determined to be the Fayetteville Works site, which had been run by DuPont since its founding in 1971 and then managed by DuPont spinoff, The Chemours Company, since 2015. The water utility confirmed they had no ability to filter these chemicals from the drinking water. NC Dpt of Environmental Quality recordshttps://edocs.deq.nc.gov/WaterResources/DocView.aspx?id=591721&&searchid=dd4b2dd5-c2ba-42e7-805c-04d21d75ab10 indicate that DuPont started release PFAS into the area beginning in 1976 with the production of Nafion, and that PFAS including GenX had been released as a byproduct of the production of Vinyl Ethers since 1980, exposing the Cape Fear Basin for decades. A small nonprofit called Cape Fear River Watch sued the NC Dept. of Environmental Quality (DEQ) for not taking swifter and stronger action, and sued the polluter, Chemours for violations of the Clean Water Act and the Toxic Substances Control Act. The result was a Consent Order,https://www.deq.nc.gov/news/key-issues/genx-investigation/chemours-consent-order signed February 25, 2019 by Cape Fear River Watch, NC Department of Environmental Quality, and Chemours.https://capefearriverwatch.org/genx/ The order has required Chemours to stop wastewater discharge, air emissions, groundwater discharge, sampling and filtration options to well users, and required sampling that proved there were upwards of 300 distinct PFAS being released from Fayetteville Works.https://www.chemours.com/en/about-chemours/global-reach/fayetteville-works/compliance-testing [244] => [245] => == Similar polymers == [246] => [[File:PFA Structure.svg|thumb|Teflon is also used as the trade name for a polymer with similar properties, [[perfluoroalkoxy polymer resin]] (PFA).]] [247] => [248] => The Teflon trade name is also used for other polymers with similar compositions: [249] => * [[Perfluoroalkoxy alkane]] (PFA) [250] => * [[Fluorinated ethylene propylene]] (FEP) [251] => [252] => These retain the useful PTFE properties of low friction and nonreactivity, but are also more easily formable. For example, FEP is softer than PTFE and melts at {{convert|533|K}}; it is also highly transparent and resistant to sunlight.[https://web.archive.org/web/20100724195156/http://www.texloc.com/closet/cl_fep_properties.htm FEP Detailed Properties], Parker-TexLoc, 13 April 2006. Retrieved 10 September 2006. [253] => [254] => == See also == [255] => * [[BS 4994]], PTFE as a thermoplastic lining for dual laminate chemical process plant equipment [256] => * [[Dark Waters (2019 film)|''Dark Waters'']], a film about litigation related to PFOA [257] => * [[The Devil We Know (film)|''The Devil We Know'']], documentary on PFOA's health and environmental effects [258] => * [[ETFE]] [259] => * [[Gore-Tex]] waterproof fabric [260] => * [[Magnesium/Teflon/Viton]], pyrolant thermite composition [261] => * [[Polymer adsorption]] [262] => * [[Superhydrophobic coating]] [263] => * [[Surface treatment of PTFE]] [264] => [265] => == Notes == [266] => {{notelist}} [267] => [268] => == References == [269] => {{reflist|30em}} [270] => [271] => == Further reading == [272] => * {{Cite journal [273] => | last1 = Ellis [274] => | first1 = D.A. [275] => | last2 = Mabury [276] => | first2 = S.A. [277] => | last3 = Martin [278] => | first3 = J.W. [279] => | last4 = Muir [280] => | first4 = D.C.G. |author5=Mabury, S.A. |author6=Martin, J.W. |author7=Muir, D.C.G. [281] => | year = 2001 [282] => | title = Thermolysis of fluoropolymers as a potential source of halogenated organic acids in the environment [283] => | journal = Nature [284] => | volume = 412 [285] => | issue = 6844 [286] => | pages = 321–324 [287] => | doi = 10.1038/35085548 [288] => | pmid = 11460160 [289] => | bibcode = 2001Natur.412..321E [290] => | s2cid = 4405763 [291] => }} [292] => [293] => == External links == [294] => * [https://web.archive.org/web/20090227022541/http://www.plasmatechsystems.com/about/pubs/Plasma%20Processes%20Polytetrafluoroethylene.pdf Plasma Processes and Adhesive Bonding of Polytetrafluoroethylene] [295] => * [https://web.archive.org/web/20100305090149/http://fluorotherm.com/Properties-PTFE.asp PTFE (polytetrafluoroethylene) (Properties) | Fluorotherm.com] [296] => [297] => {{DuPont|state=collapsed}} [298] => {{Plastics}} [299] => [300] => {{DEFAULTSORT:Polytetrafluoroethylene}} [301] => [[Category:American inventions]] [302] => [[Category:Biomaterials]] [303] => [[Category:Dielectrics]] [304] => [[Category:Dry lubricants]] [305] => [[Category:DuPont]] [306] => [[Category:DuPont products]] [307] => [[Category:Fluorocarbons]] [308] => [[Category:Fluoropolymers]] [309] => [[Category:Thermoplastics]] [310] => [[Category:Pyrotechnic oxidizers]] [311] => [[Category:Roofing materials]] [312] => [[Category:Engineering plastic]] [313] => [[Category:1938 in science]] [] => )
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Polytetrafluoroethylene

Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene. It is known for its exceptional chemical resistance, high temperature resistance, low friction properties, and electrical insulating capabilities.

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It is known for its exceptional chemical resistance, high temperature resistance, low friction properties, and electrical insulating capabilities. PTFE is widely used in various applications and industries due to its unique properties. It is commonly used as a non-stick coating for cookware, in the aerospace industry, in electrical cables and connectors, as a lubricant, and in the medical field for various purposes. PTFE was discovered by accident in 1938 by a chemist at DuPont and was later patented in 1941. Since then, it has become a widely used material in many industries and continues to be an important component in various products.

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