Talk:Polytetrafluoroethylene

message: I came here to find that out, and I don't see it on the main page. This could one of those "universal solvent"-type questions but it might have a simple answer. I'm guessing an intermediate layer of something with a bond to the carbons on one side and to the steel on the other....--Hugh7 (talk) 08:20, 4 November 2010 (UTC)
thread_title: What makes it stick to the frying pan?

message: The 'picture' of PTFE is of a kinked line. For that structure to exist, the chemical formula would need to include some C=C (carbon-carbon double bonds).
However the chemical structure given suggests that the carbon structure is saturated with fluorine?--Ryan Wise (talk) 17:54, 30 May 2010 (UTC)
replies: text: I think the point is that it's a flexible chain - the picture below the structure is perfectly compatible.Lexyboy (talk) 14:43, 27 August 2010 (UTC)
thread_title: shape vs. chemical structure

message: Do we need to mention about the fact that supposidly Teflon was a by-product of the space programme? 'The Ninjalemming' 18:23, 24 February 2009 (UTC)
thread_title:  Space plan thingy 

message: It is interesting that it was invented as the result of a accident.  What other compounds have been so invented or discovered?  Would it be worthwhile to have a category for this? SlowJog (talk) 13:59, 26 June 2009 (UTC)
replies: text: Lots are, it would be a very, very large section. 82.132.139.215 (talk) 17:29, 18 September 2009 (UTC)
replies: text: Or a alphabetical list. If needed, it could be distributed on on several pages. SlowJog (talk) 02:33, 27 September 2009 (UTC)

text: I did not mean to suggest a section on accidental inventions be added to this article. I meant to suggest a Wikipedia category be created (if there isn't one already), and this article linked to the category. SlowJog (talk) 15:27, 22 May 2010 (UTC)
thread_title:  Category for accidental discovery / inventions 

message: Why is there no mention of ICI and "Fluon" in this article?
Ksmill (talk) 14:24, 3 September 2009 (UTC)
thread_title:  ICI (Imperial Chemical Industries) 

message: How much of this article is true? Any of it that's true deserves to be in Wiki:
http://www.ecomall.com/greenshopping/teflon4.htm
:Is this source a reliable source (see WP:RS for info on what is a reliable source).  Reading the link, I would say no it isn't.  However if there are other sources which have similar info (say from newpapers) then this info is worth examining.  Shot info (talk) 05:42, 8 March 2010 (UTC)
thread_title:  Teflon Death 

message: I have marked section "Safety" as disputed. It only demonstrates one point of view. Please consider stating opposite claims and studies. Ahmediq152 (talk) 15:57, 13 October 2010 (UTC)
replies: text: I removed the tag because you did not cite any "alternate" studies why they conflict with the section. Please explain before tagging again thanks. -Shootbamboo (talk) 21:25, 13 October 2010 (UTC)
thread_title:  Safety: single point of view 

message: See also: "Harmful Teflon Chemical To Be Eliminated by 2015". Can anybody explain how Teflon compares to coatings like Thermolon?  —Preceding unsigned comment added by 85.223.52.7 (talk) 20:17, 11 March 2011 (UTC)
thread_title: Thermolon

message: There's nothing in the article about public suspicion that Teflon can be cancerogenic (the word cancer is only one and hidden in the hame of 18th reference) and about last judicial trials against most Teflon manufacturers. Such information need to be added for the full picture of this material. Also there's already many alternative materials to Teflon - i found three of them: Bio-Lon, Thermolon and Ecolon. Westsomething (talk) 05:37, 2 December 2011 (UTC)
thread_title:  Cancerogenic concerns and class action suits against Teflon manufacturers 

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thread_title: File:Centre Pompidou-Metz en juin 2010.jpg Nominated for Deletion

message: It's well-documented in the scientific literature that PTFE chains adopt a helical conformation, but this isn't mentioned in the article. I think it's a simple, interesting point that has an effect on the physical properties of the polymer (several order-disorder phase transitions around room temperature). I'm not an expert in polymers or PTFE, so I'm floating the idea here first. Which section should it go in?
I've updated the 3D diagram in the infobox - it's actually of a perfluorodecyl chain in a medium-sized organic molecule, but it has the same helical conformation as PTFE and is an experimentally determined structure (single crystal x-ray diffraction).
Here are some references:
* "The molecular conformations of polytetrafluoroethylene: forms II and IV", E. S. Clark, Polymer (1999) 40, 4659–4665
* "Modeling of helix reversal defects in polytetrafluoroethylene: II. Molecular dynamics simulations" D. B. Holt, B. L. Farmer, Polymer (1999) 40, 4673–4684
* "Conformational and orientational order and disorder in solid polytetrafluoroethylene", M. Sprik, U. Rothlisberger, M. L. Klein, Mol. Phys. (1999) 97, 355–373
* "Periodic and high-temperature disordered conformations of polytetrafluoroethylene chains: An ab initio modeling", M. D'Amore, G. Talarico, V. Barone, J. Am. Chem. Soc. (2006) 128, 1099–1108
There's a good, brief summary of the current state of knowledge on PTFE conformation and phase transitions in J. Phys. Chem. A (2010) 114, 1118–1122. 
Also discussed at Alkane stereochemistry#Special cases, which cites J. Am. Chem. Soc. (2006) 128, 6000–6001.
Ben (talk) 23:50, 27 December 2011 (UTC)
thread_title:  Conformation 

message: This thing is a very high view topic.  Wish we had a GA.  10 years into this thing and a lot of fundamental content is not done.  I keep finding more stuff to do as I work on one article...it is all connected.TCO (Reviews needed) 01:32, 1 January 2012 (UTC)
thread_title:  50,000 hits per month 

message: Or at least a section!
What we have now is way skimpy.  And the Gore-tex page is not appropriate since it is about a fabric laminate, and a PU/PTFE membrane, not the ePTFE.
TCO (Reviews needed) 23:30, 2 January 2012 (UTC)
thread_title:  I proposed a separate article on ePTFE 

message: This section needs to be rewritten to include that this chemical is not safe, especially in light of recent court proceedings against DuPont. This chemical has been linked to prostate cancer, birth defects, and respiratory infections. Studies by DuPont have proven that there is no safe level of consumption of this poisonous chemical. Please see: http://highline.huffingtonpost.com/articles/en/welcome-to-beautiful-parkersburg/?ncid=fcbklnkushpmg00000063  — Preceding unsigned comment added by 172.8.146.166 (talk) 22:01, 30 August 2015 (UTC)
replies: text: The information in the "Safety" section seems more or less okay, but the presentation is a bit garbled.  It needs to be re-written.  — Preceding unsigned comment added by 108.20.253.150 (talk) 04:06, 6 June 2012 (UTC)

text: That article says that C8, aka Perfluorooctanoic acid, is toxic. Polytetrafluoroethylene, which is what this article is about, is not. --Ahecht (TALKPAGE) 02:58, 4 April 2022 (UTC)
thread_title:  "Safety" section needs re-writing 

message: The section on uses, radiometry mentions the use of PTFE for optical diffusers. A very important point that is not mentions is the fact that PTFE has a room temperature (19 C) phase transition that affects its optical transmission and electrical properties. For uses a diffusers in the near UV the effect is an approximately 2% change in the transmission.
http://dx.doi.org/10.1016/j.optmat.2004.11.008
http://dx.doi.org/10.1109/NSSMIC.1991.258937
http://www.micro-coax.com/pages/technicalinfo/applications/27.asp
http://dx.doi.org/10.1021/j100013a035  — Preceding unsigned comment added by 67.161.253.189 (talk) 16:40, 9 June 2012 (UTC)
thread_title:  Radiometry/Optical Properties 

message: But there is a source for one of the "citation missing" statements.
http://www.sealing.com/fileadmin/docs/Using_Bellville_springs_to_maintain_bolt_preload.pdf
"Sometimes metal springs are used to apply continuous force to PTFE seals, giving good contact while permitting a beneficially low percentage of creep.[citation needed]"
454Casull (talk) 14:01, 16 May 2014 (UTC)
replies: text: I put it in as currently Reference 21.  The "Citation needed" tag was taken out.  H Padleckas (talk) 04:21, 18 May 2014 (UTC)
thread_title:  Not sure how to add a reference (yet) 

message: The Applications section needs references to compare industrial and consumer-cookware uses to eliminate the "other" paragraph. Because cookware doesn't actually use much polymer?  Is cookware an application where the polymer is created in-place, thus not made by chemical company and shipped to them?165.121.80.222 (talk) 18:26, 21 July 2014 (UTC)
thread_title:  Applications section 

message: Of the materials listed in the Electrical Conductivity article, Teflon has the lowest conductivity.   But it's not a comprehensive list of all materials.  Is there another material with even lower conductivity?
If Teflon has the lowest conductivity of any known material, that's a pretty notable property that should be mentioned in the article. 75.163.166.82 (talk) 15:22, 9 August 2014 (UTC)
thread_title:  Record-low conductivity? 

message: I have just removed (from the article) the following paragraph:
:::Another major application is in fuel and hydraulic lines, due to PTFE's low resistance against flowing liquids. Colder temperatures at high altitudes cause these fluids to flow more slowly. Coating the lines's interior surfaces with low-resistance PTFE helps to compensate by allowing the liquids to move more easily.
This statement was attributed to Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim. , but in this form it is completely false. The author must have confused hydraulic/hydrodynamic resistance to flow with chemical resistance, which is the most important reason of using PTFE in tubings and hoses. Low friction of teflon has nothing to do with the case of flow of liquid - at least as long as the diameter of the tubing is much largar than of the order of several hundred nanometer. The flow rate of pressure driven laminar flow of any liquid in a tubular pipe is given by Hagen–Poiseuille equation and the assumption of no-slip condition is always valid for liquids in the macroscopic scale. If this is not enough, the hypothesis of "low resistance of teflon against flowing liquid" was explicitely falsified by scientific experiments over 50 years ago - Journal of Research of the National Bureau of Standards, Vol. 58, No. 1, January 1957. Research Paper 2734. Resistance of Flow in Teflon and Brass Tubes, , and there is the link. I can agree that PTFE is widely used in hydraulic and fuel lines, but the reasons are completely different than "allowing the liquids to move more easily". Tescobar (talk) 16:26, 2 September 2014 (UTC)
thread_title:  Low resistance against flowing liquid ??? 

message: The decomposition into CF4 and C is unlikely to be the initial reaction in the exothermic reaction of TFE monomer. explosive  polymerization of bulk monomer is a well documented phenomena with alkene monomers. For example, styrene explosive polymerization has 2 million hits on google search. As the TFE runaway polymerization proceeds and temperature and pressure build, the reaction may change to that which forms CF4 and carbon.  TFE is usually polymerized by emulsion polymerization in water to control heat buildup and limit viscosity to prevent poor heat transfer.  — Preceding unsigned comment added by 66.194.206.214 (talk) 11:26, 25 March 2016 (UTC)
thread_title:  unstable monomer 

message: Dry_lubricant#Polytetrafluorethylene says it has low surface energy but its not mentioned here. - Rod57 (talk) 10:59, 13 August 2017 (UTC)
thread_title:  low surface energy 

message: I have little understanding of chemistry and am reading to learn more and found the following confusing:
In the "History" section it says:
"In the 1990s, it was found that PTFE could be radiation cross-linked above its melting point in an oxygen-free environment.[16] Electron beam processing is one example of radiation processing. Cross-linked PTFE has improved high-temperature mechanical properties and radiation stability. This was significant because, for many years, irradiation at ambient conditions has been used to break down PTFE for recycling.[17] This radiation-induced chain scission allows it to be more easily reground and reused."
But then in the "Properties" section it says:
"Because of its chemical inertness, PTFE cannot be cross-linked like an elastomer."
Can PTFE be cross-linked or not?  Maybe there are different kinds of cross-linking and that could be clarified in the text in those two places.
thank you.
2601:1C2:600:EF6:A8E5:71E:1F69:DEFC (talk) 21:15, 31 December 2018 (UTC)
replies: text: Very good question. I'm not a chemist either. Have you read ref #17? --Quisqualis (talk) 07:08, 1 January 2019 (UTC)
thread_title:  seemingly conflicting content in the article as currently written. 

message: Why is there a PFOA section in this article? These are different chemicals. Ratel (talk) 03:21, 9 May 2019 (UTC)
replies: text: This struck me as odd as well.  I think a sentence mentioning its use as a surfactant in the manufacturing process along with a reference and a wikilink to the main PFOA article would be appropriate.  Everything else may belong in the PFOA article, but is out of place here.MDK33 (talk) 17:15, 7 February 2020 (UTC)
thread_title:  PFOA section? 

message: Really there shouldn't be any references to 'fact sheets' from industries like the wastewater industry that has taken a strongly anti-regulatory position (see ref 60, for example, and for the lobbying efforts and spending by this industry, .  — Preceding unsigned comment added by 75.174.217.203 (talk) 21:41, 24 August 2020 (UTC)
replies: text: I agree with you and I've removed the text. Tell me if there is more. Ratel 🌼 (talk) 03:06, 25 August 2020 (UTC)
thread_title:  This wiki has quite a biased anti-regulation position. 

message: Another characteristic of PTFE of great significance is that the dielectric constant (the electrical equivalent of optical index of refraction) does not change over a very wide range of frequencies. That is, as an insulating medium, it has very little dispersion. Thus wide bandwidth signals can propagate without delay distortion caused by differences in speed of propagation with frequency. I know I need a reference, but I believe this because, for years, I would see an add from a company that made teflon capacitors that included a graph showing the lack of dispersion. --AJim (talk) 15:57, 22 September 2020 (UTC)
replies: text: You're correct. I remember in the 1980s I worked in a microwave materials characterization lab. We used reflectometers and transmissions systems to characterize the dielectric constant and loss tangent for various materials (or the effective constants for composite materials). We measured teflon's dielectric properties as flat across the spectrum from 2 to 100 GHz (the range of equipment we had); about 6 frequency octaves. For a dense solid, PTFE has an unusually low dielectric constant of of about 2.0 and negligible loss. ~Anachronist (talk) 19:23, 22 September 2020 (UTC)
thread_title:  dispersion 

message: An editor has identified a potential problem with the redirect :Teflon® and has thus listed it for discussion. This discussion will occur at Wikipedia:Redirects for discussion/Log/2022 April 15#Teflon® until a consensus is reached, and readers of this page are welcome to contribute to the discussion.  BD2412 T 05:07, 15 April 2022 (UTC)
thread_title:  "Teflon®" listed at [[Wikipedia:Redirects for discussion|Redirects for discussion]] 

message: Why is the term "forever chemicals" not mentioned even a single time in the current version of this article? 173.88.246.138 (talk) 23:54, 5 June 2022 (UTC)
replies: text: I was thinking the same - the whole article looks like an advertisement, heavily downplaying or ignoring the problems, like DuPont's documented chronic lies. I'll need to do more research on this. 2001:7D0:8412:5D80:AC26:B124:510:7118 (talk) 11:45, 30 June 2022 (UTC)
thread_title: "[[Forever chemicals]]"

message: The point about jewelry in the applications section states "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." while the latter temperatures are likely meant in °C, as shown below in the first sentence of the safety section. Also there is no citation for that acrylic releases toxins at 26.6 °C. In addition there should be a space before the °C symbol, like "26.6 °C" instead of "26.6°C" and "toxins" instead of "toxics". Also the 26.6 might be in °F, since the PTFE decomposition temperature is wrong in the same way. 92.224.202.135 (talk) 21:26, 16 December 2022 (UTC)
thread_title:  Application for jewelry 

message: Speak Karthivikram (talk) 14:42, 27 December 2022 (UTC)
thread_title:  Polytetrafluoroethylene 

message: There are conflicting statements regarding the decomposition temperature of PTFE, see the 2 quotes below. Given that PTFE is regularly used above 200 °C, I doubt that the first number (200 °C decomposition) is correct. Hence I checked the source of that number and this is what it says:
: There are several types of Teflon fluorocarbon resins in commercial use, each differing in thermal stability and therefore differing in the amounts of the several decomposition products evolved at various temperatures.
: [...]
: There is no hazard from pyrolysis products of Teflon fluorocarbon resins at temperatures of 200°C and below. Above 200°C, where pyrolysis of the resin is detectable, several fluorocarbon gases and a sublimate are evolved.
"Teflon fluorocarbon resins" is defined as: 
: *“Teflon” is the resistered trademark of the DuPont Company for its TFE and FEP fluorocarbon resins. This Guide pertains to “Teflon” TFE (polymer of tetrafluoroethylene) and FEP (polymer of fluorinated ethylene propylene) fluorocarbon resins.
Hence I will remove that, since it is not about PTFE but instead the less stable FEP and TFE.
: == Processing ==
: Processing PTFE can be difficult and expensive, because the high melting temperature, 327 °C (621 °F), is above the initial decomposition temperature, 200 °C (392 °F).
: == Safety ==
: While PTFE is stable at lower temperatures, it begins to deteriorate at temperatures of about 260 °C (500 °F), it decomposes above 350 °C (662 °F), and pyrolysis occurs at temperatures above 400 °C (752 °F).
Eheran (talk) 11:59, 2 May 2024 (UTC)
thread_title:  Thermal stability conflicting numbers