ETFE

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. 

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). 

The molecular weight and its distribution have been determined by laser light scattering, employing a new apparatus for ETFE dissolution and solution clarification at high temperature diisobutyl adipate is the solvent at 240°C. The molecular weight of molten ETEE is determined by high temperature rheometry (21). 

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. 

Modified ethylene—tetrafluoroethylene copolymers are commercially available ia a variety of physical forms (Table 6) and can be fabricated by conventional thermoplastic techniques. Commercial ETFE resias are marketed ia melt-extmded cubes, that ate sold ia 20-kg bags or 150-kg dmms. In the United States, the 1992 price was 27.9—44.2/kg, depending on volume and grade color concentrates are also available. 

Molten ETFE polymers corrode most metals, and special corrosion-resistant alloys ate recommended for long-term processiag equipmeat short-term prototype mas are possible ia standard equipment. 

Coloring and Decorating. Commercial pigments that are thermally stable at the resin processing temperature maybe used. Pigments maybe dry-blended with the resin, or ETFE pellets may be blended with color concentrates, which are available ia pellet form. 

Modfed ETFE-Fluorocarbon Molding and Extrusion Materials, ASTM D3159-83, American Society for Testing and Materials, Philadelphia, 1987. 

ETFE Tefzel ethylene-tetrafluoroethylene copolymer. (For chemical resistance, see FEP ratings.) Tefzel is a Du Pont registered trademark. 

Fig. 11. Effect of polyolefin primers on bond strength of ethyl cyanoacrylate to plastics. All assemblies tested in accordance with ASTM D 4501 (block shear method). ETFE = ethylene tetrafluoroethylene copolymer LDPE = low-density polyethylene PFA = polyper-fluoroalkoxycthylene PBT = polybutylene terephthalate, PMP = polymethylpentene PPS = polyphenylene sulfide PP = polypropylene PS = polystyrene PTFE = polytetrafluoroethylene PU = polyurethane. From ref. [73].

Polyester (PETP, PBTP) Fluorocarbons (PTFE, PFA, FEP and ETFE)... 

ETFE CF2=CF2 CH2CH2 CF2=CFORf or CH2=CHRf Aflon COP Halon ET Hostaflon ET Neoflon EP Tefzel Asahi Glass Ausimont Hoechst Dai km Du Pont Japan Italy USA Germany Japan USA... 

Even though potential memory exists in all TPs, polyolefins, neoprenes, silicones, and other cross-linkable TPs are example of plastics that can be given memory either by radiation or by chemically curing. Fluorocarbons, however, need no such curing. When this phenomenon of memory is applied to fluorocarbons such as TFE, FEP, ETFE, ECTFE, CITE, and PVF2, interesting high-temperature or wear-resistant applications become possible. 

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