Copolymers of Ethylene and Tetrafluoroethylene ETFE

Copolymers of ethylene and tetraflnoroethylene essentially comprise alternating ethylene and TFE nnits. They have an excellent balance of physical, chemical, mechanical, and electrical properties and are easily fabricated by melt-processing techniques but have found little commercial utility because they exhibit a poor resistance to cracking at elevated temperatures [59], Incorporation of certain termonomers, so-called modifiers, in amounts 1 to 10 mol% markedly improves the cracking resistance, while maintaining the desirable properties of the copolymer [60,61], ETFE resins are manufactured by several companies under different trade names. 

The carbon chain is in a planar zigzag orientation and forms an orthorhombic lattice with interpenetration of adjacent chains [61], As a result of this structure, ETFE has an exceptionally low creep, high tensile strength, and high modulus compared with other thermoplastic fluoropolymers. Interchain forces hold this matrix until the alpha transition occurs at about 110°C (230°F), where the physical properties of ETFE begin to decline and more closely resemble perfluoropolymer properties at the same temperature. Other transitions occur at -120°C (-184°F) (gamma) and about -25°C (-13°F) (beta) [62]. 

The monomer ratio in the copolymer has an effect on the polymer structure and properties, mainly on the degree of crystallinity and on the melting point. As normally produced, ETFE has about 88% of alternating sequences and a melting point of 270°C (518°F) [63], 

Continuous upper service temperature of commercial ETFE is 150°C (302°F) [64]. Physical strength can be maintained at even higher temperatures when the polymer is cross-linked by peroxide or ionizing radiation [65], Highly cross-linked resins can be subjected to temperatures up to 240°C (464°F) for short periods of time [64]. 

ETFE exhibits excellent dielectric properties. Its dielectric constant is low and essentially independent of frequency. The dissipation factor is low but increases with frequency and can be also increased by cross-linking. Dielectric strength and resistivity are high and are unaffected by water. Irradiation and cross-linking increase dielectric loss [64], 

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The copolymer of ethylene and tetrafluoroethylene (ETFE) can be cross-linked by irradiationl Furfher improvemenf is achieved wifh fhe use of prorads, such as TAG or TAIC, in amounfs up fo 10%. 

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... 

Creasy and Brenna ° continued their previous work by examining a copolymer of ethylene and tetrafluoroethylene (ETFE), polyphenylene sulfide (EPS), and a diamond-like carbon film (DEC). Ablation of these samples gave comparison information on the formation of fullerenes in the presence of H, S, and F atoms. In the case of ETFE, a large Cso peak was observed in the spectra, which showed a strong dependence on the number of laser pulses and laser power density. 

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. ... 

ETFE — Copolymer of ethylene and tetrafluoroethylene noted for an exceptional chemical resistance, toughness, and abrasion resistance. 

Note ETFE, copolymer of ethylene and tetrafluoroethylene ECTFE, copolymer of ethylene chlorotrif- ... 

Note ETFE, copolymer of ethylene and tetrafluoroethylene MFA, copolymer of perfluoromethylvi-nylether and tetrafluorethylene PFA, copolymer of perfluoropropylvinylether and tetrafluoroethylene FEP, fluorinated ethylene-propylene copolymer PCTFE, poly(chlorotrifluoroethylene) PVDF, poly(vinylidene fluoride) VDF-HFP, copolymer of vinylidene fluoride and hexafluoropropylene. 

Copolymers of ethylene with tetrafluoroethylene (ETFE) and chlorotrifluoroethylene (ECTFE) are mechanically stronger than perfluoropolymers, with some reduction in their chemical resistance and continuous use temperature and an increase in the coefficient of friction. 

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. 

ETFE is a copolymer of ethylene and tetrafluoroethylene similar to ECTFE, but with a higher use temperature. It does not have the flame F F F CFg... 

ETFE is sold under the trade name of Tefzel by DuPont. It is a partially fluori-nated copolymer of ethylene and tetrafluoroethylene with a maximum service temperature of 300 F/149°C. Tefzel can be melt bonded to untreated aluminum, steel, and copper. It can also be melt bonded to itself. In order to adhesive bond Tefzel with polyester or epoxy compounds, the surface must be chemically etched or subjected to corona or flame treatments. 

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. 

Commercial ETFE is an equimolar copolymer of ethylene and tetrafluoroethylene (1 1 ratio) and is isomeric with polyvinylidene fluoride. ETFE has a higher melting point than PVDF and a lower dissipation fac-torl l because of its special chain conformation. Crystalline density was 1.9 g/cm for a polymer containing 12% head-to-head defect, The unit cell of the crystal is expected to be orthorhombic or monoclinic with cell dimensions of a = 0.96 nm, b = 0.925 nm, c = 0.50 nm and 7= 96°. 

ETFE polymers are melt processible. Commercial ETFE is a copolymer of ethylene and tetrafluoroethylene. They have lower chemical resistance and thermal stability than perfiuorinated polymers. ETFE exhibits excellent resistance to radiation and can stand up to 200 megarads of exposure to cobalt 60. It is a tough thermoplastic available in different viscosities, which can be processed by techniques applicable to polyethylene. ETFE resins are specified by ASTM Method D3159, which also provides procedures or references to other ASTM methods for the measurement of resin properties. Commercial FEP resins offered by major manufacturers have been listed in Tables 6.15 through 6.18. 

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. 

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. 

ETFE is a copolymer of tetrafluoroethylene and ethylene. The TFE/ethylene ratio is greater than 75%, leading to fluorine contents of about 60% or more. 

Copolymers of tetrafluoroethylene and ethylene are highly crystalline and fragile at elevated temperatures and are modified by a third monomer. Production of ETFE terpolymers having improved high temperature mechanical (especially tensile) properties has been demonstrated. They comprise of 40-60 mol% ethylene, 40-60 mol% tetrafluoroethylene, and a small amount of a polymerizable vinyl termonomer, such as perfluoroisobutylene, perfluoropropyl vinyl ether, and hexafluoropropylene. 

Polytetrafluoroethylene (PTFE Teflon) was discovered accidently by PlunkettCZ nd commercialized by DuPont in the 1940 s. This polymer has a solubility parameter of about 6H and a high melting point of 327°C and is not readily moldable. Poly-chlorotrifluoroethylene (CTFE, Kel-F), the copolymer of tetrafluoroethylene and hexafluoropropylene (FEP), polyvinylidene fluoride (PVDF, Kynar), the copolymer of tetrafluoroethylene and ethylene (ETFE), the copolymer of vinylidene fluoride and hexafluoroisobutylene (CM-1), perfluoroalkoxyethylene (PFA) and polyvinyl fluoride (PVF, Tedlar) are all more readily processed than PTFE. However, the lubricity and chemical resistance of these fluoropolymers is less than that of PTFE. 

Fluoroplastics are a class of paraffinic polymers that have some or all of the hydrogen replaced by fluorine. These include polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP) copolymer, perfluoroalkoxy (PFA) resin, polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoro-ethylene (ECTFE) copolymer, ethylene-tetrafluoroethylene (ETFE) copolymer, polyvinylidene fluoride (PVDF), and polyvinylfluoride (PVF) [186],... 

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