1.What is PTFE?
PTFE is the abbreviation of polytetrafluoroethylene. It is a synthetic fluoropolymer that combines carbon and fluorine. PTFE, and other fluoropolymers alike, such as FEP and PFA, shares similar fields of applications. The fluoropolymer is the main material to make tubing for medical, pharmaceutical, chemical, and other industrial equipment. Aside from tube making, PTFE is an ideal material for coating as well. Applying a PTFE layer onto metals, fabric, and other materials improves a given product’s quality. In this article, we will talk about the properties and applications as well as other aspects with respect to the use of PTFE.
2.Is PTFE the same as Teflon?
Yes, PTFE is Teflon. There are tons of terminologies out there for plastics, polymers, and synthetic materials. It easily gets confusing for people to figure out exactly which is what and we get it. PTFE is the chemical term. It indicates what this material is. Teflon is the brand name owned by the company Chemours. Teflon was discovered in 1938 by DuPont’s chemist, Dr. Roy Plunkett, and later managed by Dupont’s spin-off company, Chemours. Chemours registered the trademark Teflon in 1945. Today, the company is still developing PTFE products with higher performance under the brand name Teflon.
3.How is PTFE made?
PTFE is made by polymerizing TFE (tetrafluoroethylene) and the main ingredients are fluorspar, chloroform, and hydrofluoric acid. The process starts by synthesizing these three ingredients to produce TFE. This step is called pyrolysis. It is a chemical reaction process where these ingredients are heated to between 590-900 degrees Celsius in an autoclave to fuse together. TFE comes in the form of a colorless (transparent), odorless, and toxic-free gas. TFE is highly flammable and explosive so it is almost impractical to transport the material. Therefore, the polymerization of TFE is usually conducted on-site, right after the production of TFE. Making PTFE requires cooling and distilling to purify TFE prior to the polymerizing process.
The polymerization of high-purity TFE involves the use of the initiator (reaction agent) and pure water. PTFE manufacturers use different recipes and initiators in their own polymerization process. The agent can be bisulfites, di-tertbutyl peroxide, disuccinic acid peroxide, ammonium persulfate (APS), and azo-based initiators, to just name a few. In terms of the process, the two main methods are dispersion polymerization and suspension polymerization. The former method produces PTFE paste that can be further processed into fine powder. It is ideal for metal coating and fabric finishing. The latter makes PTFE pellets, which can be molded, sintered, etc. into various PTFE products.
4.What are the properties of Teflon?
Teflon is applicable in fields that demand products with durable and robust physical properties, for instance medical, automotive, electronics, military industries, etc. Here are the major characteristics of Teflon.
Item
Unit
ASTM Test
Method
PTFE
(4F)
PFA
PCTFE
(3F)
PVDF
(2F)
FEP
(4-6F)
PEEK
Physical
Properites
Density
D792
2.14~2.2
2.12~2.17
2.1~22
1.75~2.17
2.12~2.17
1.31
Melting Point
oC
327
302~310
210~212
170
253~282
340
Mechanical
Properties
Note : PEEK is not a Fluropolymer, it is listed only for comparison purposes under high pressure and temperature operating environment.
4.1.Heat and chemical resistance
First of all, Teflon is heat-resistant. Or, to be exact, Teflon can withstand high temperatures compared with other plastic materials. It has a melting point of around 327 degrees Celsius so there are few circumstances heat damages Teflon. Secondly, Teflon is chemically inert. It does not react to most chemicals, which makes it preferable in the chemical, petrochemical, and pharmaceutical industry where the equipment handles corrosive chemicals on a daily basis.
4.2.Low friction coefficient
Another essential characteristic of Teflon is its low friction coefficient. This is what most people describe as the non-stick property. Chemically speaking, the molecules of Teflon are wrapped by fluorine. Fluorine on the surface layer prevents other materials from attaching to PTFE. That is why Teflon has the non-stick property. This trait is especially beneficial to the cookware. The non-stick pan is so convenient that we can find at least one piece of cookware with the Teflon coating in virtually every household today. That being said, Teflon coating is applied on other products to minimize friction or provide a better surface finish.
4.3 Wear/weathering resistance & electrical insulation
PTFE not only resists heat and chemicals. It has little to no friction, is resistant to wear and weather, and has good electrical insulation. PTFE can work and maintain high performance over time in harsh working environments due to its excellent wear and weathering resistance. It can hold out against pressure and forces, making it a good protection material for equipment in outdoor settings. The low electrical conductivity is ideal for semiconductor manufacturers. So, what are some common applications?
5.Applications
The application of Teflon is nearly limitless with all these benefits. Most people think of cookware when it comes to Teflon. However, there is more to PTFE’s application. In the following section, we are going to talk about some PTFE-involved products people are not aware of.
5.1.Lubricant
PTFE is used as dry lubrication in areas where low friction is required, with cookware coating being one of them. PTFE can reduce the friction effectively between surfaces and it gives an additional protection layer against corrosive substances as well. The WD-40 spray with PTFE is used for chain lubrication. It leaves a thin film on the chain so that it can resist dirt and oil.
5.2.Piping/tubing
As mentioned earlier, Teflon coating is on the surface of the piping/tubing system in facilities that handle highly corrosive fluid. The Teflon coating on the inner surface of valves, pumps, tees, fittings, and every joint in the piping system is crucial for it prevents the risk of fluid leakage. The leakage of corrosive fluid is hazardous to both the equipment and the staff members in the working area.
5.3.Fabric/textile
One of the benefits we haven’t mentioned yet is the hydrophobic property. Teflon is water repellent and can easily coat fibers. Outdoor clothing brands use the technology to design garments and shoe fabrics to make water-repellent products. The famous, and probably the most successful waterproof fabric, Gore-tex, derives from PTFE. Gore-tex is a patented fabric called ePTFE (expanded PTFE), which is renowned for its waterproof yet breathable characteristics.
5.4.Ammunition
A fluoropolymer is a fluorocarbon-based polymer with multiple carbon–fluorine bonds. The best known fluoropolymer is polytetrafluoroethylene(PTFE).
Fluoropolymers have superior heat resistance, chemical resistance, good electrical insulation. Besides the above characteristics, fluoropolymers also carry nonstick and low-frictional properties.
The best known fluoropolymer is polytetrafluoroethylene(PTFE), and it exhibits outstanding resistance to chemical, resists all chemicals except fluorine gas, chlorine trifuloride, and molten alkali metals. But when in high temperature, PCTFE is slightly susceptible to ammonia and chlorine gas.
Among fluoropolymers, PTFE exhibits the lowest frictional coefficient and provides unique self-lubricating properties.
It can be used up to 260 degree C.Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. The commonly known brand name of PTFE-based compositions is Teflon™ by Chemours, a spin-off from DuPont, which originally discovered the compound.
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