Ethylene tetrafluoroethylene mechanical properties

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. ... 

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... 

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. 

The alternating copolymer of trifluorochloroethylene and ethylene has a higher melting temperature of 240° C. It has similar mechanical properties to poly(vinylidene fluoride) or the alternating copolymer of tetrafluoroethylene and ethylene. 

Partially fluorinated materials include ECTFE (ethylene trifluoroethylene), ETEE (ethylene tetrafluoroethylene), and PVDE (polyvinylidene fluoride). The partially fluorinated materials have higher mechanical properties but lower temperature ratings (<300°E/149°C), and chemical resistance. 

Weathering and light resistance of ethylene-tetrafluoroethylene-copolymer are excellent. After over 2000 h of weathering in a Weatherometer, its mechanical properties are not impaired [83]. 

Copolymers of ethylene and tetrafluoroethylene (ETFE) essentially comprise alternating ethylene and TFE units. They have an excellent balance of physical, chemical, mechanical, and electrical properties, 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... 

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. 

Hexafluoropropylene is produced by the pyrolysis of tetrafluoro-ethylene. The copolymer of hexafluoropropylene with tetrafluoroethylene is a medium-grade thermoplast with a crystallinity of 40-50% (drawn) to 50-70 % (annealed). The copolymer has similar mechanical and chemical properties to poly(tetrafluoroethylene), but can be molded and extruded. 

Polymers are widely used as implant materials because they have physical properties that are similar to those of natural tissues. Examples are long-term and shortterm implants such as blood vessels, heart valves, membranes, mesh prostheses, corneas, tracheal prostheses, dental materials, parts of the nose and ear, knee and hip joints, and others. The synthetic polymers used include polyethylene (PE), particularly ultrahigh molecular weight PE (UHMWPE), poly(ethylene terephthal-ate) (PET), poly(tetrafluoroethylene) (PTFE), polyurethane (PU), and poly(methyl methacrylate) (PMMA). The necessary sterilization before implantation can be performed by y-irradiation, heat (steam), or chemical treatment (ethylene oxide), which should not cause any structural degradation of the polymers. Current challenges in research include the development of biomimetic materials that match both the mechanical and biological properties of their natural counterparts. 

The relaxation behavior of partially crystalline systems is complex and different from amorphous polymers. Observations give the general impression that, in comparison to amorphous systems, partially crystalline samples are much less uniform in behavior. Many of the systems exhibit peculiarities and these can dominate the viscoelastic properties. This is not the place to explore this large field in the necessary depth, which would mean we would have to discuss separately the mechanical behavior of polyethylene, poly(ethylene terephtha-late), polypropylene, it-polystyrene, poly(tetrafluoroethylene) etc. What can be done for illustration is to pick out one instructive example and we select polyethylene. 

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