FEP | |
---|---|
CAS Registry Number | 25067-11-2 |
Density [1] | 2150 kg/m3 |
Flexural modulus(E) | 586 M Pa |
Tensile strength(t) | 23 M Pa |
Elongation @ break | 325% |
Folding endurance | Varies |
Notch test | |
Melting point | 260 °C |
Maximum operating | |
temperature | 204 °C |
Water absorption (ASTM) | <0.01 % after 24 hours |
Dielectric constant (Dk) | |
at 1M Hz | 2.1 |
Dissipation factor | |
at 1M Hz | 0.0007 |
Arc resistance | < 300 seconds |
Resistivity at 50% R.H. | > 1016 Ω m |
Fluorinated ethylene propylene (FEP) is a copolymer of hexafluoropropylene and tetrafluoroethylene. It differs from the polytetrafluoroethylene (PTFE) resins in that it is melt-processable using conventional injection molding and screw extrusion techniques. [2] Fluorinated ethylene propylene was invented by DuPont and is sold under the brandname Teflon FEP. Other brandnames are Neoflon FEP from Daikin or Dyneon FEP from Dyneon/3M.
FEP is very similar in composition to the fluoropolymers PTFE (polytetrafluoroethylene) and PFA (perfluoroalkoxy polymer resin). FEP and PFA both share PTFE's useful properties of low friction and non-reactivity, but are more easily formable. FEP is softer than PTFE and melts at 260 °C; it is highly transparent and resistant to sunlight. [3] [4]
FEP is produced by free-radical polymerization of mixtures of tetrafluoroethylene and hexafluoropropylene. The mixture is biased to compensate for the relatively low reactivity of the propylene component. The process is typically initiated with peroxydisulfate, which homolyzes to generate sulfate radicals. Because FEP is poorly soluble in almost all solvents, the polymerization is conducted as an emulsion in water, often using a surfactant such as perfluorooctanesulfonic acid (PFOS). The polymer contains about 5% of the propylene component. [2]
Useful comparison tables of PTFE against FEP, perfluoroalkoxy (PFA) and ethylene tetrafluoroethylene (ETFE) can be found on Chemours website, listing the mechanical, thermal, chemical, electrical and vapour properties of each, side by side. [5]
In terms of corrosion resistance, FEP is the only other readily available fluoropolymer that can match PTFE's own resistance to caustic agents, as it is a pure carbon-fluorine structure and fully fluorinated.[ failed verification ] [6]
Thermally, FEP stands out from PTFE and PFA by having a melting point of 260 °C (500 °F), around 40°C lower than PFA and lower again than PTFE. [5]
Electrically, PTFE, FEP and PFA have identical dielectric constants, but FEP's dielectric strength is only surpassed by PFA. However, while PFA has a similar dissipation factor to PTFE, FEP's dissipation is around six times that of PFA and EFTE (making it a more non-linear conductor of electrostatic fields).[ failed verification ] [5]
Mechanically, FEP is slightly more flexible than PTFE. It does not withstand repetitive folding as well as PTFE. It also features a higher coefficient of dynamic friction, is softer and has a slightly lower tensile strength than PTFE and PFA. [6]
A noteworthy property of FEP is that it is vastly superior to PTFE in some coating applications involving exposure to detergents.[ failed verification ] [6]
Ethylene tetrafluoroethylene (ETFE), in many ways, can be thought of as belonging to a different group, as it is essentially a high strength engineering version of the others featuring what are likely to be considered slightly diminished properties in the other fields when compared with PTFE, FEP and PFA.[ failed verification ][ original research? ] [6]
Like PTFE, FEP is mainly used for wiring, e.g. hookup wire, coaxial cable, wiring for computer wires and technical gear. [2] An illustrative end product is for coaxial cables like RG-316.
In manufacturing high-quality composite parts, such as in the aerospace industry, FEP film can be used to protect parts during the curing process. In such applications, the film is called "release film" and is intended to prevent the curing adhesive polymer (e.g. the epoxy in a carbon fibre/epoxy composite laminate) from bonding to the vacuum bagging materials. Being able to maintain chemical composure in extreme temperatures and resist damage from chemical fuels further makes FEP a suitable choice in the industry. [7]
Semi-finished products like pipes, [8] round bars, [8] and sheets [8] for lining containment vessels, gas scrubbers, and tanks are being used in diverse applications in the chemical-processing industry to safely contain and distribute highly-aggressive chemical compounds.
Due to its flexibility, extreme resistance to chemical attack and optical transparency, this material, along with PFA is routinely used for plastic labware and tubing that involves critical or highly corrosive processes. Brand GmbH, Finemech, Savillex and Nalgene are well known laboratory suppliers that makes extensive use of the two materials.
It is also used in UV cured resin 3D printing. Due to the aforementioned properties of high optical transparency and low friction, it is ideally suited for use on the bottom of the resin reservoir (opposite the build plate). This allows for the ultraviolet light to penetrate into the resin, then after the layer has hardened, the build plate can move away pulling the hardened resin away from the FEP film.
The plastic is useful as a sample holder material in microscopy applications as its refractive index is close to that of water at visible wavelengths, [9] [10] (FEP: 1.344, water: 1.335). This minimizes the blur due to optical aberrations when the light traverses the sample container.
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, a spin-off from DuPont, which originally discovered 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.
Roy Joseph Plunkett was an American chemist. He discovered polytetrafluoroethylene (PTFE), better known as Teflon, in 1938.
Gore-Tex is W. L. Gore & Associates's trade name for waterproof, breathable fabric membrane. It was invented in 1969. Gore-Tex blocks liquid water while allowing water vapor to pass through and is designed to be a lightweight, waterproof fabric for all-weather use. It is composed of expanded PTFE (ePTFE), a stretched out form of the PFAS compound polytetrafluoroethylene (PTFE).
A fluoropolymer is a fluorocarbon-based polymer with multiple carbon–fluorine bonds. It is characterized by a high resistance to solvents, acids, and bases. The best known fluoropolymer is polytetrafluoroethylene under the brand name "Teflon," trademarked by the DuPont Company.
Heat-shrink tubing is a shrinkable plastic tube used to insulate wires, providing abrasion resistance and environmental protection for stranded and solid wire conductors, connections, joints and terminals in electrical wiring. It can also be used to repair the insulation on wires or to bundle them together, to protect wires or small parts from minor abrasion, and to create cable entry seals, offering environmental sealing protection. Heat-shrink tubing is ordinarily made of a polyolefin, which shrinks radially when heated, to between one-half and one-sixth of its diameter.
Ethylene tetrafluoroethylene (ETFE) is a fluorine-based plastic. It was designed to have high corrosion resistance and strength over a wide temperature range. ETFE is a polymer and its source-based name is poly (ethene-co-tetrafluoroethene). It is also known under the DuPont brand name Tefzel and is sometimes referred to as 'Teflon Film'. ETFE has a relatively high melting temperature and excellent chemical, electrical and high-energy radiation resistance properties.
Tetrafluoroethylene (TFE) is a fluorocarbon with the chemical formula C2F4. It is the simplest perfluorinated alkene. This gaseous species is used primarily in the industrial preparation of fluoropolymers.
ECTFE (ethylene-chlorotrifluoroethylene) is an alternating copolymer of ethylene and chlorotrifluoroethylene. It is a semi-crystalline fluoropolymer, with chemical corrosion resistance properties.
FKM is a family of fluorocarbon-based fluoroelastomer materials defined by ASTM International standard D1418, and ISO standard 1629. It is commonly called fluorine rubber or fluoro-rubber. FKM is an abbreviation of Fluorine Kautschuk Material. All FKMs contain vinylidene fluoride as the common monomer, to which different other monomers are added for specific types and functionalities, fitting the desired application.
Teflon is a registered trademark of the Chemours company used for polytetrafluoroethylene.
Perfluoroethers are a class of organofluorine compound containing one or more ether functional group. In general these compounds are structurally analogous to the related hydrocarbon ethers, except for the distinctive properties of fluorocarbons.
A 'non-stick surface' is engineered to reduce the ability of other materials to stick to it. Non-sticking cookware is a common application, where the non-stick coating allows food to brown without sticking to the pan. Non-stick is often used to refer to surfaces coated with polytetrafluoroethylene (PTFE), a well-known brand of which is Teflon. In the twenty-first century, other coatings have been marketed as non-stick, such as anodized aluminium, silica, enameled cast iron, and seasoned cookware.
Electron-beam processing or electron irradiation (EBI) is a process that involves using electrons, usually of high energy, to treat an object for a variety of purposes. This may take place under elevated temperatures and nitrogen atmosphere. Possible uses for electron irradiation include sterilization, alteration of gemstone colors, and cross-linking of polymers.
Hexafluoropropylene oxide (HFPO) is an intermediate used in industrial organofluorine chemistry; specifically it is a monomer for fluoropolymers. This colourless gas is the epoxide of hexafluoropropylene, which is a fluorinated analog of propylene oxide, HFPO is produced by DuPont and 3M and as a precursor to the lubricant Krytox and related materials. It is generated by oxidation of perfluoropropylene, e.g. with oxygen as well as other oxidants.
A perfluorinated compound (PFC) or perfluoro compound is an organofluorine compound that lacks C-H bonds. Many perfluorinated compounds have properties that are quite different from their C-H containing analogues. Common functional groups in PFCs are OH, CO2H, chlorine, O, and SO3H. Electrofluorination is the predominant method for PFC production. Due to their chemical stability, some of these perfluorinated compounds bioaccumulate.
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The global market for chemicals from fluorine was about US$16 billion per year as of 2006. The industry was predicted to reach 2.6 million metric tons per year by 2015. The largest market is the United States. Western Europe is the second largest. Asia Pacific is the fastest growing region of production. China in particular has experienced significant growth as a fluorochemical market and is becoming a producer of them as well. Fluorite mining was estimated in 2003 to be a $550 million industry, extracting 4.5 million tons per year.
Perfluoroalkoxy alkanes (PFA) are fluoropolymers. They are copolymers of tetrafluoroethylene (C2F4) and perfluoroethers (C2F3ORf, where Rf is a perfluorinated group such as trifluoromethyl (CF3)). The properties of these polymers are similar to those of polytetrafluoroethylene (PTFE). Compared to PTFE, PFA has better anti-stick properties and higher chemical resistance, at the expense of lesser scratch resistance.
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Herbert S. Eleuterio was an American industrial chemist noted for technical contributions to catalysis, polymerization, industrial research management, and science education. In particular, he discovered the olefin metathesis reaction and several novel fluoropolymers. Additionally, he explored techniques for research leadership, especially methods for fostering collaboration, globalization, and scientific creativity.