Fluorinated Ethylene-Propylene FEP

Eluorinated ethylene propylene is a copolymer of TFE and hexafluoropropylene and has a branched structure containing units of -CF2-CF2- and -CE2-CE (CEj)-. It retains most of the favorable properties of PTFE, but its melt viscosity is low enough for conventional melt processing. The introduction of HEP reduces the melting point of polytetrafluoroethylene from 327°C (621°E) to about 260°C (500°F) [37]. 

Fluorinated ethylene-propylene is a fully fluorinated thermoplastic with some branching, but it mainly consists of linear chains having the following formula  

The chemicals listed are in the pure state or in a saturated solution unless otherwise indicated. Compatibility is shown to the maximum allowable temperature for which date is available. Incompatibility is shown by an X. A blank space indicates that data is unavailable. 

Source From P.A. Schweitzer. 2004. Corrosion Resistance Tables, Vols. 1-4,5th ed.. New York Marcel Dekker. 

FEP has a maximum operating temperature of 375°F (190°C). After prolonged exposure at 400°F (204°C), it exhibits changes in physical strength. To improve some physical and mechanical properties, the polymer is filled with glass fibers. 

FEP basically exhibits the same corrosion resistance as PTFE with few exceptions but at lower operating temperatures. It is resistant to practically all chemicals except for extremely potent oxidizers such as chlorine trifluoride and related compounds. Some chemicals will attack FEP when present in high concentrations at or near the service temperature limit. Refer to Table 2.15 for the compatibility of FEP with selected corrodents. Reference [1] provides a more detailed listing. 

---

Fluorinated polymers stand out sharply against other construction materials for their excellent corrosion resistance and high-temperature stability. In this respect they are not only superior to other plastics but also to platinum, gold, glass, enamel and special alloys. The fluorinated plastics used in process plants are polytetrafluorethylene (PTFE), fluorinated ethylene/ propylene (FEP), polytrifiuoromonochlorethylene (PTFCE) and polyvinyl fluoride (PVF). They are much more expensive than other polymers and so are only economical in special situations [59]. 

Poly(tetrafluoroethylene) (PTFE) Poly(chlorotrifluoroethylene) (PCTFE) Perfluoroalkoxy (PFA) resin Fluorinated ethylene-propylene (FEP) resin... 

FEP polymer, 10 220 18 306—307. See also Fluorinated ethylene propylene (FEP) Perfluorinated ethylene-propylene (FEP) copolymers applications of, 18 315—316 chemical properties of, 18 313 dispersion processing of, 18 314 economic aspects of, 18 315 effects of fabrication on properties of, 18 315... 

Fluorinated diacyl peroxides, 76 472 Fluorinated epoxy resins, 70 366-367 Fluorinated ethylene propylene (FEP), for copper wire, 7 691. See also FEP polymer... 

Fluorinated ethylene propylene (FEP), copolymer of tetrafluoroethylene (TEE) and hexafluoropropylene (HFP) has physical and chemical properties similar to those of PTFE but differs from it in that FEP can be processed by standard melt-processing techniques. 

The principal kinds of thermoplastic resins include (1) acrylonitrile-butadiene-styrene (ABS) resins (2) acetals (3) acrylics (4) cellulosics (5) chlorinated polyelliers (6) fluorocarbons, sucli as polytelra-fluorclliy lene (TFE), polychlorotrifluoroethylene (CTFE), and fluorinated ethylene propylene (FEP) (7) nylons (polyamides) (8) polycarbonates (9) poly elliylenes (including copolymers) (10) polypropylene (including copolymers) ( ll) polystyrenes and (12) vinyls (polyvinyl chloride). The principal kinds of thermosetting resins include (1) alkyds (2) allylics (3) die aminos (melamine and urea) (4) epoxies (5) phenolics (6) polyesters (7) silicones and (8) urethanes,... 

Appliance wires require a higher temperature rating (105°C or higher). Therefore, the insulation is made of fluorinated thermoplastics, such as p oly- tetr aflu o r o ethylene (PTFE) or fluorinated ethylene—propylene (FEP). 

Examples of fluoroplastics include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), ethylene—chlorotrifluoroethylene (ECTFE), ethylene—tetrafluoroethylene (ETFE), poly(vinylidene fluoride) (PVDF), etc (see Fluorine compounds, organic). These polymers have outstanding electrical properties, such as low power loss and dielectric constant, coupled with very good flame resistance and low smoke emission during fire. Therefore, in spite of their relatively high price, they are used extensively in telecommunication wires, especially for production of plenum cables. Plenum areas provide a convenient, economical way to run electrical wires and cables and to interconnect them throughout nonresidential buildings (14). Development of special flame-retardant low smoke compounds, some based on PVC, have provided lower cost competition to the fluoroplastics for indoors application such as plenum cable, Riser Cables, etc. 

The need for highly fluorinated thermoplastic polymers that, unlike PTFE, could be fabricated by conventional melt-processing methods led to the development of a group of resins that are copolymers of tetrafluoroethylene (TFE) with other perflu-orinated monomers. Commercially, the copolymer of TFE and hexafluoropropylene (HFP) is commonly known as fluorinated ethylene propylene (FEP). Copolymerization of TFE with perfluoropropylvinyl ether (PPVE) leads to PFA resins, and copolymerization of TFE with perfluoromethylvinyl ether (PMVE) produces MFA resins. 

This kind of contamination was carefully evaluated by using various labware glass and quartz tubes, polytetrafluoroethylene (PTFE) vessels, fluorinated ethylene propylene (FEP) and perfluoroalkoxy (PFA) tubes. Ideally, all trace element determinations should be carried out in clean rooms in which the incoming air is filtered and special clothing is worn. 

Fluorinated ethylene propylene (FEP) Pol y tet raftuoroe th ylene (FTFE) Polyvinyl fluoride (PVF) Polyvinylidene fluoride (PVDF) lonomer Ketone... 

The family of FPs, also called fluorocarbon plastics, is based on polymers made of monomers composed of fluorine and carbon may also include chlorine atoms in their structure. Specific types include polytetrafluoroethylene (PTFE), polytetrafluoroethylene-cohexafluoro-propylene or fluorinated ethylene propylene (FEP), polytrafluoroethylene-coperfluoropropylvinyl ether (PFA), ethylenetetrafluoroethylene (ETFE). polychlorotrifluoroethylene (PCTFE), ethylene-chlorotri-fluoroethylene (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), perfluoromethylvinylether (PFMV), perfluoroalkoxy (PFA), etc. 

Fluorinated ethylene propylene (FEP), a copolymer of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP), is essentially PTFE with an occasional methyl side group attached. The methyl groups have effect as defects in crystallites and therefore reduce the melting point. These side groups also impede the slipping of the polymer chains past each other, thus reducing the cold flow. 

HFP Hexafluoropropylene, a monomer used for the production of fluorinated ethylene propylene (FEP) and other copolymers (e.g., THV thermoplastic) and of fluorinated elastomers. 

Apparatus for preparations. All reactions were performed with a stainless steel vacuum line. Preparations were carried out in Teflon reactors assembled especially for each. The reactors were joined to the metal line via flexible fluorinated ethylene propylene (FEP) tubes and a polytetrafluoroethy-lene (PTFE) valve. FEP-tube reactors were prepared by first cutting lengths to —25 cm. These tubes were softened at one end by heating in a flame, then squeezed with broad-nose pliers to seal the end. One-armed reactors consisted of one of these tubes connected directly to a PTFE valve. T-shaped reactors had two of these tubes connected to a PTFE T-joint, which itself was connected via FEP tubing to a PTFE valve. All reactors were made vacuum-tight with PTFE swage connections. 

Storage of water samples to detect trace metals is normally carried out in plastic containers fluorinated plastic materials i.e.. Teflon, fluorinated ethylene propylene (FEP), perfluoroalkoxy polymers (PFA) or polyethylene are used because if opportunely treated and conditioned they guarantee contamination-free samples. However, FEP or Teflon bottles are preferable to those made of polyethylene when speciation studies are carried out. In fact, polyethylene over long periods of storage can release plasticizers (above all phthalates or amines), which behave as ligands and modify the complexation equilibria of the solution. When Hg is to be determined plastic materials must be avoided because they are permeable to gases and vapours glass or quartz are therefore used. 

Teflon [Du Pont], TM for tetrafluoroethyl-ene (TFE) fluorocarbon polymers available as molding and extrusion powders, aqueous dispersion, film, finishes, and multifilament yam or fiber. The name also applies to fluorinated ethylene-propylene (FEP) resins available in the same forms. The no-stick cookware finishes may be of either type. Fibers are monofilaments made from copolymer of TFE and FEP. 

PVDF is the third most widely used fluoropolymer, after polytetrafluoroethylene (PTFE) and fluorinated ethylene-propylene (FEP). The worldwide consumption of PVDF was approximately 15,000 metric tons in 2001 and is growing at an annual rate of 6-8%. PVDF applications have been expanded over the past 40 years because of its unique physical properties, and have over 30 years of proven and field performance data on thermal, chemical, radiation, and weathering applications. PVDF applications include, but are not limited to, chemical processing of pipes and components, semiconductor, architectural finishes and coatings, electrical plenum, cable jacketing. 

Over the years constmction of the dynamic chamber has been modified. For studies conducted recently, the chamber is generally constmcted as follows. The dynamic flow-through chamber system is cylindrical in nature and built from Plexiglas material. Chamber dimensions may vary but are generally about 23 cm inner diameter (i.d.) and 46 cm. in height. The entire closed system is lined on the inside with 2 mil fluorinated ethylene propylene (FEP) Teflon and stainless steel fittings in order to minimize chemical reactions with sample flow. 

---