Ethylene-Tetrafluoroethylene ETFE Elastomer

This elastomer is sold under the trade name Tefzel by DuPont. ETFE is a modified partially fluorinated copolymer of ethylene and polytetrafluor-oethylene (PTFE). Since it contains more than 75% TEE by weight, it has better resistance to abrasion and cut-through than TEE while retaining most of the corrosion resistance properties. 

Ethylene-tetrafluoroethylene has outstanding resistance to sunlight, ozone, and weather. This feature, coupled with its wide range of corrosion resistance, makes the material particularly suitable for outdoor applications subject to atmospheric corrosion. 

Ethylene-tetrafluoroethylene is inert to strong mineral acids, inorganic bases, halogens, and metal salt solutions. Even carboxylic acids, anhydrides, aromatic and aliphatic hydrocarbons, alcohols, aldehydes, ketones, ethers, esters, chloro-carbons, and classic polymer solvents have little effect on ETFE. 

Very strong oxidizing acids near their boiling points, such as nitric add at high concentration, will affect ETFE in varying degrees, as will organic bases such as amines and sulfonic acids. 

Refer to Table 5.24 for the compatibility of ETFE with selected corrodents. TABLE 5.24 

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Extrusion-Applied Insulations. The polymers used in extrusion applications can be divided into two classes low-temperature applications and high-temperature applications. Polymers in the first category are poly(vinyl chloride), polyethylene, polypropylene, and their copolymers along with other elastomers. Polymers in the second category are mainly halocarbons such as Teflon polytetrafluoroethylene (which requires special extrusion or application conditions), fluoroethylene-propylene copolymer (FEP), perf luoroalkoxy-modified polytetrafluoroethylene (PFA), poly(ethylene-tetrafluoroethylene) (ETFE), poly(vinylidene fluoride) (PVF2) (borderline temperature of 135 °C), and poly(ethylene-chlorotrifluoroethylene). Extrusion conditions for wire and cable insulations have to be tailored to resin composition, conductor size, and need for cross-linking of the insulating layer. 

A large volume of literature exists for PO blends with easily crosslinkable elastomers, but the information on radiation processing and degradation of HTPB is scarce. For dimensionally recoverable applications a blend of LCP with PVDF or PE was radiation crosslinked. Similarly, PSF or PES was blended with water-soluble PVP and crosslinked to make it water insoluble for medical or food applications. For the use in cable jackets and heat-shrinkable applications PVDF or a copolymer of tetrafluoroethylene and ethylene (ETFE) could be compounded with a thermoplastic elastomer, formed and radiation crosslinked. Adjusting composition and irradiation dose produced a series of materials with good balance of tensile strength and elongation. ... 

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