Ethylene tetrafluoroethylene (ETFE) is a fluorine-based plastic. It was designed to have high corrosion resistance and strength over a wide temperature range. ETFE is a polymer and its source-based name is poly(ethene-co-tetrafluoroethene). ETFE has a relatively high melting temperature and excellent chemical, electrical and high-energy radiation resistance properties. When burned, ETFE releases hydrofluoric acid.
ETFE is effectively the high-strength version of fluropolymer
Combustion of ETFE occurs in the same way as a number of other fluoropolymers, in terms of releasing hydrofluoric acid (HF). HF is extremely corrosive and toxic, and so appropriate caution must be exercised.
ETFE film is self-cleaning (due to its nonstick surface) and recyclable. It is prone to punctures by sharp edges and therefore mostly used for roofs. As a film for roofing it can be stretched and still be taut if some variation in size, such as that caused by thermal expansion, were to occur. Employing heat welding, tears can be repaired with a patch or multiple sheets assembled into larger panels.
ETFE has an approximate tensile strength of 42 MPa (6100 psi), with a working temperature range of 89 K to 423 K (−185 °C to +150 °C or −300 °F to +300 °F).
ETFE resins are resistant to ultraviolet light. An artificial weathering test (comparable to 30 years’ exposure) produced almost no signs of film deterioration.
ETFE was developed by DuPont in the 1970s initially as a lightweight heat resistant film in the aerospace industry. From its development it was largely used infrequently in agricultural and architectural projects.
Another key use of ETFE is for the covering of electrical and fiber-optic wiring used in high-stress, low-fume-toxicity and high-reliability situations. Aircraft, spacecraft and motorsport wiring are primary examples. Some small cross-section wires like the wire used for the wire-wrap technique are coated with ETFE.
As a dual laminate, ETFE can be bonded with FRP as a thermoplastic liner and used in pipes, tanks, and vessels for additional corrosion protection.
ETFE is commonly used in the nuclear industry for tie or cable wraps and in the aviation and aerospace industries for wire coatings. This is because ETFE has better mechanical toughness than PTFE. In addition, ETFE exhibits a high-energy radiation resistance and can withstand moderately high temperatures for a long period.
Due to its high temperature resistance ETFE is also used in film mode as a mold-release film. ETFE film offered by Guarniflon or Airtech International and Honeywell is used in aerospace applications such as carbon fiber pre-preg curing as a release film for molds or hot high-pressure plates.
Ethylene Tetra Fluoro Ethylene (ETFE) foils have increasingly been used since the 1980's for roofs and building claddings. They are transparent, light and flexible; therefore they broaden the scope of large transparent structures. Their properties allow designing of structures that would have been impossible to build using standard materials such as glass. Foils can be used in single or multi-layer configurations. Multi-layer applications, such as inflated cushions, allow better insulation of the buildings to be attained. Popular applications for ETFE foils are greenhouses, large halls for swimming pools or recreational parks, shopping malls roofs and atria .As far as cladding is concerned, transparency of ETFE foils is often combined with special lighting in order to obtain spectacular effects. In the last decade, the potential of ETFE foils has been demonstrated.
ETFE foils combine numerous advantages for being used in civil engineering. First of all they are lightweight with approximate 350 g/m2 it is approximately 100 times lighter than glass allowing large span structures to be built. They have excellent light transmission, even higher than comparable glass or polycarbonate elements. Their durability is extremely long due to a very high resistance to chemicals and UV exposure, and they are also at the top pyramid of polymers in terms of fire retardation. Due to their surface properties, these foils are also self-cleaning and do not need further care. Contrary to glass that is brittle, ETFE-foils are ductile and do not shatter when they fail. Finally, they are environment-friendly as they can be recycled by heating and require10 times less energy per m2 than glass for their production.
More detailed typical physical and mechanical properties of clear ETFE foils are summarized in below table
Thickness 12-500 µm
50-300 µm for architectural use
Density 1.7-1.77 g/cm3
Light transmission 90-97% of visible light
Use temperature -200 to 150°C
Melting temperature 250-280°C
Tensile strength 40-64 MPa
Extension at failure 250-300%
Tensile modulus 300-1100 MPa
Poisson's ratio 0.43-0.45