Ethylene-tetrafluoroethylene copolymer properties

Thermal properties. See also Temperature of aromatic polyamides, 19 718 of asbestos, 3 300-304 of diesel fuel, 12 423 of ethylene—tetrafluoroethylene copolymers, 18 319-321 of fibers, 11 167 of filled polymers, 11 309—310 of gallium, 12 342 of glass, 12 588... 

Polyvinylidene fluoride (PVDF) and Ethylene tetrafluoroethylene copolymer (ETFE) can be considered as diluted PTFE s, which in their structure and their properties... 

Ethylene Tetrafluoroethylene Copolymer - Thermoplastic comprised of an alternating copolymer of ethylene and tetrafluoroethylene. Has high impact resistance and good abrasion resistance, chemical resistance, weatherability, and electrical properties approaching those of fully fluori-nated polymers. Retains mechanical properties from cryogenic temperatures to 356°F. Can be molded, extruded, and powder-coated. Used in tubing, cable and wire products, valves, pump parts, wraps, and tower packing in aerospace and chemical equipment applications. Also called ETFE. 

An increase in the high temperature (200 °C) tensile properties of the ethylene-tetrafluoroethylene copolymer, ETFE, after irradiation in nitrogen at room temperature followed by heat treatment at 162 °C in nitrogen for 20 min indicates some crosslinking [118]. On the other hand, irradiatimi carried out in air showed very little cross-linking [119]. ETFE behaves in some ways similar to poly-vinyUdene fluoride (PVDFO in that there is competition between crosslinking and scissimi. Some of the tensile properties, measured at 200 °C, of irradiated ETFE are shown in Table 52.14 [119]. 

Ethylene-tetrafluoroethylene copolymer (ETFE) is a linear macromolecule with the monomer unit [—(CHjlj—(CF l —] . ETFE exhibits physical properties similar to those of ethyl-ene-chlorotrifluoroethylene copolymer. 

Ethylene-Tetrafluoroethylene Copolymer n A copolymer of ethylene and tetrafluoroethylene (DuPont Tefzel ), ETFE is readily processed by extrusion and injection molding. It has excellent resistance to heat, abrasion, chemicals, and impact, with good electrical properties. 

Weathering and light resistance of ethylene-tetrafluoroethylene-copolymer are excellent. After over 2000 h of weathering in a Weatherometer, its mechanical properties are not impaired [83]. 

Copolymeis of ethylene [74-85-1] and tetiafluoioethylene [116-14-3] (ETFE) have been alaboiatory curiosity for more than 40 years. These polymers were studied in connection with a search for a melt-fabricable PTFE resin (1 5) interest in them fell with the discovery of TFE—HFP (FEP) copolymers (6). In the 1960s, however, it became evident that a melt-fabricable fluorocarbon resin was needed with higher strength and stiffness than those of PTFE resins. Earlier studies indicated that TFE—ethylene copolymers [11939-51 -6] might have the right combination of properties. Subsequent research efforts (7) led to the introduction of modified ethylene—tetrafluoroethylene polymer [25038-71-5] (Tefzel) by E. I. du Pont de Nemours Co., Inc, in 1970. 

The inability to process PTFE by conventional thermoplastics techniques has nevertheless led to an extensive search for a melt-processable polymer but with similar chemical, electrical, non-stick and low-friction properties. This has resulted in several useful materials being marketed, including tetrafluoro-ethylene-hexafluoropropylene copolymer, poly(vinylidene fluoride) (Figure 13.1(d)), and, most promisingly, the copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether. Other fluorine-containing plastics include poly(vinyl fluoride) and polymers and copolymers based on CTFE. 

PVC, another widely used polymer for wire and cable insulation, crosslinks under irradiation in an inert atmosphere. When irradiated in air, scission predominates.To make cross-linking dominant, multifunctional monomers, such as trifunctional acrylates and methacrylates, must be added. Fluoropolymers, such as copol5miers of ethylene and tetrafluoroethylene (ETFE), or polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), are widely used in wire and cable insulations. They are relatively easy to process and have excellent chemical and thermal resistance, but tend to creep, crack, and possess low mechanical stress at temperatures near their melting points. Radiation has been found to improve their mechanical properties and crack resistance. Ethylene propylene rubber (EPR) has also been used for wire and cable insulation. When blended with thermoplastic polyefins, such as low density polyethylene (LDPE), its processibility improves significantly. The typical addition of LDPE is 10%. Ethylene propylene copolymers and terpolymers with high PE content can be cross-linked by irradiation. ... 

Copolymers of tetrafluoroethylene were developed in attempts to provide materials with the general properties of PTFE and the melt process-ability of the more conventional thermoplastics. Two such copolymers are tetrafluoroethylene-hexafluoropropylene (TFE-HFP) copolymers (Teflon FEP resins by Du Pont FEP stands for fluorinated ethylene propylene) with a melting point of 290°C and tetrafluoroethylene-ethylene (ETFE) copolymers (Tefzel by Du Pont) with a melting point of 270°C. These products are melt processable. A number of other fluorine containing melt processable polymers have been introduced. 

Fluoriuated Ethylene Propylene Copolymer Thermoplastic copolymer of tetrafluoroethylene and hexafiuoro-propylene. Has deereased tensile strength and wear and creep resistanee, but good weatherability, dielectric properties, fire and ehemical resistance, and friction. Decomposes above 204°C (400°F), releasing toxic products. Processed by molding, extrusion, and powder coating. Used in chemieal apparatus liners, pipes, containers, bearings, films, eoatings, and cables. Also called FEP. 

Hexafluoropropylene is produced by the pyrolysis of tetrafluoro-ethylene. The copolymer of hexafluoropropylene with tetrafluoroethylene is a medium-grade thermoplast with a crystallinity of 40-50% (drawn) to 50-70 % (annealed). The copolymer has similar mechanical and chemical properties to poly(tetrafluoroethylene), but can be molded and extruded. 

The melt processible fluoroplastics are often desired due to the cost benefits of melt extrusion over paste extrusion. FEP, PEA and specially formulated melt processible perfluoroplastics are used in many of these applications however, in some of these applications, perfluoroplastics may not be the ideal choice. In cases where high cut-through resistance and better tensile properties are required, it is often desirable to employ a partially fluorinated polymer such as ETFE (ethylene-tetrafluoroethylene). ETFE is the copolymer of ethylene and TEE [16] that normally includes an additional termonomer to increase the flexibility required in commercial applications [17]. The increased physical and electronic interactions of the ETFE polymer chain are responsible for the comparatively enhanced physical properties. Additionally, the partially fluorinated polymers may be cross-linked to further improve physical properties. These benefits, however, are obtained at the expense of the unique properties of perfluoroplastics discussed in the Introduction and Overview. 

Poly(Ethylene-Tetrafluoroethylene) n (PE-TFE) A crystalline resin in which the proportion of ethylene to tetrafluoroethylene (E/TFE) may range, for the best combination of properties, between 2 3 and 3 2, modified with a vinyl copolymer for better toughness. It is stronger than either low-density polyethylene or polytetrafluoroethylene, has good electrical properties, high Izod-impact strength, and plastic memory that makes it useful for heat-shrinkable packaging. 

Unlike poly(tetrafluoroethylene), copolymers of tetrafluoro-ethylene with perfluoro comonomers are made as relatively low molecular weight (i.e., low melt viscosity) products that can be processed by conventional melt procedures and stiU have properties in the soUd state that are simUar or superior to those of poly(tetrafluoroethylene). Both PFA, poly[tetrafluoroethylene-co-perfluoro(alkoxy vinyl ether)]. 

The most chemical-resistant plastic commercially available today is tetrafluoroethylene or TFE (Teflon). This thermoplastic is practically unaffected by all alkahes and acids except fluorine and chlorine gas at elevated temperatures and molten metals. It retains its properties up to 260°C (500°F). Chlorotrifluoroethylene or CTFE (Kel-F, Plaskon) also possesses excellent corrosion resistance to almost all acids and alkalies up to 180°C (350°F). A Teflon derivative has been developed from the copolymerization of tetrafluoroethylene and hexafluoropropylene. This resin, FEP, has similar properties to TFE except that it is not recommended for continuous exposures at temperatures above 200°C (400°F). Also, FEP can be extruded on conventional extrusion equipment, while TFE parts must be made by comphcated powder-metallurgy techniques. Another version is poly-vinylidene fluoride, or PVF2 (Kynar), which has excellent resistance to alkahes and acids to 150°C (300°F). It can be extruded. A more recent development is a copolymer of CTFE and ethylene (Halar). This material has excellent resistance to strong inorganic acids, bases, and salts up to 150°C. It also can be extruded. 

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. 

Fluoropolymers, such as copolymer of ethylene and tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), are widely used in wire and cable insulations. They are relatively easy to process and have excellent chemical and thermal resistance, but tend to creep, crack and possess low mechanical stress at temperatures near their melting points. Radiation has been found to improve their mechanical properties and crack resistance.36... 

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