ETFE copolymer

These values indicate strong alternation tendencies that decrease with increasing temperature. Computations show that 1 1 ETFE copolymers obtained at —30 and 65°C should have about 97 and 93%, respectively, of alternating sequences (15). 

Thermal Properties. Modified ETFE copolymer has a broad operating temperature range up to 150°C for continuous exposure (24). Cross-linking by radiation improves the high temperature capabiUty further. However, prolonged exposure to higher temperatures gradually impairs the mechanical properties and results in discoloration. 

Commercial products based on copolymers of ethylene and TEE are made by free radical-initiated addition copolymerization.69 Small amounts (1 to 10 mol%) of modifying comonomers are added to eliminate a rapid embrittlement of the product at exposure to elevated temperatures. Examples of the modifying comonomers are perfluorobutyl ethylene, hexafluoropropylene, perfluorovinyl ether, and hexafluoro-isobutylene.70 ETFE copolymers are basically alternating copolymers,70 and in the molecular formula, they are isomeric with polyvinylidene fluoride (PVDF) with a head-to-head, tail-to-tail structure. However, in many important physical properties, the modified ETFE copolymers are superior to PVDF with the exception of the latter s remarkable piezoelectric and pyroelectric characteristics. 

ETFE copolymers can be readily fabricated by a variety of melt-processing techniques.19 They have a wide processing window, in the range 280 to 340°C (536 to 644°F) and can be extruded into films, tubing, and rods or as thin coating on wire and cables. Injection molding of ETFE into thin sections is considerably easier than injection molding of melt-processible perfluoropolymers because the former has... 

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. 

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],... 

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. 

Polytetrafluoro- ETFE Copolymers with ethylene Tefzel... 

Both crystalline forms of ETFE copolymers may be considered as mesomorphic forms [250-253]. In the low-temperature form, the chains are in the ordered trans planar conformation and are packed in a polyethylenelike orthorhombic lattice [250,251]. However, intermolecular order is present... 

Feng et al. tested SIMS as an analytical technique for distinguishing between two polymers having an identical composition and a similar chain sequence structure ethylene-tetrafluoroethylene (ETFE) copolymer and poly(vinylidene fluoride) (PVDF) [142]. The positive ToF-SIMS spectra, obtained under 8 kV Cs" bombardment, showed that ETFE generates Q, C2, C3, C4, and C5 ions, while PVDF only produces Ci, C2, and C3 ions. These results clearly imply that sequence structure can significantly influence the positive SIMS spectra of... 

Tetrafluoroethylene-ethylene (ETFE) copolymers resemble the tetra-fluoroethylene-hexafluoropropylene copolymers discussed in the preceding section in that they too can be melt processed by standard techniques. 

The ETFE copolymer is a melt processable resin with a crystalline melting point of around 270 C. Its excellent cut-through resistance has made the copolymer advantageously applicable to wire coating. 

The membrane development for PEMFCs comprises many steps. The multiple steps in monomer synthesis for PFS A preparation are often said to be one of the major factors in the high cost of the PFSA membranes. In fact, FIFE and ethylene-tetrafluoroethylene (ETFE) copolymer, whose synthetic scheme is very simple, are available at comparably low price. As a matter of fact, a considerably large quantity of the ETFE sheet was used in the stadium. 

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