Teflon EPE

Somewhat between PTFE and PFA materials is the product Hostaflon TFM, which is a copolymer of TFE and a small amount of the perfluoro(propyl vinyl ether). It has improved impact strength and weldability and has been promoted as a suitable material for forming into bottles. Yet another TFE-perfluoroalkoxy copolymer was introduced by Du Pont in 1979 as Teflon EPE. This material had a somewhat lower melting point (295 °C) than the more common PFA fluoropolymers but it is no longer marketed. 

With commercialization of PFA and "TEFZEL" in 1972 a burst of enthusiasm for polymers combining the various structural characteristics ensued. Polymers developed included terpolymers of TFE/HFP/PPVE ("TEFLON" EPE [11], "Hostaflon" TFA and "TEFLON" FEE [12]). The former polymers have certain modest property advantages over blends of FEP with PFA, However, these advantages have not been sufficient to generate enthusiastic use in industry. The FEE copolymers are more interesting since, despite their hydrocarbon content, they have a balance of properties quite similar to those of PFA (Table IV), They are superior to PFA in two ways ... 

A phase transition occurs in Teflon at 19°C, and this involves a change in the degree of helical structure. It may be observed [59] as a spectral change in a weak doublet-type Raman band at 598 and 577 cm A few copolymers of tetrafluoroethylene exist, including tetrafluor-oethylene-hexafluoropropylene (FEP), tetrafluoroethylene-perfluoroalkyl-vinylether (PFA), and tetrafluoroethylene-hexafluoropropylene-perfluo-roalkylvinylether (EPE). An example of the IR and Raman spectra of EPE is provided in Reference Spectrum 24. Although these three copolymers have similar IR spectra, the bands around 990 cm are used to distinguish these copolymers [60]. The hexafluoropropylene moiety of FEP produces a band at 982 cm while the perfluoroalkyl vinylether moiety of PFA has a band at 993 cm As expected, EPE exhibits both the 993 and the 982 cm bands. The IR spectrum in Reference Spectrum 24 shows the 993 cm band as a shoulder on the 982 cm band. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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