ETFE

ETFE
Names
	IUPAC name poly(1,1,2,2-tetrafluorobutane-1,4-diyl)
	Other names poly(ethene-co-tetrafluoroethene)
Identifiers
CAS Number	25038-71-5 ;
ChemSpider	none;
CompTox Dashboard (EPA)	DTXSID10880370 ;
	InChI InChI=1S/C2F4.C2H4/c3-1(4)2(5)6;1-2/h;1-2H2 Key: QHSJIZLJUFMIFP-UHFFFAOYSA-N ;
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

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). It is also known under the DuPont brand name Tefzel and is sometimes referred to as 'Teflon Film'. ETFE has a relatively high melting temperature and excellent chemical, electrical and high-energy radiation resistance properties.

Properties

Useful comparison tables of PTFE against FEP, PFA and ETFE can be found on Chemours' website, listing the mechanical, thermal, chemical and electrical properties of each, side by side.^[1] ETFE is effectively the high-strength version of the other three in this group.

ETFE film is self-cleaning (due to its nonstick properties) and recyclable.^[2] 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).^[3]

ETFE resins are resistant to ultraviolet light. An artificial weathering test (comparable to 30 years’ exposure) produced no filtering and almost no signs of film deterioration.^[4]

ETFE systems can control light transmission through the application of plasma coatings, varnishes or printed frit patterns.^[5] Thermal and acoustic insulation can be incorporated into an ETFE structure via the use of multi-layer systems which use low-pressure air pumps to create ETFE "cushions".^[6] For instance u value of ETFE single layer, double and three layers are approximately: 5.6, 2.5 and 1.9 W/m2.k respectively^[7] while concerning g value of etfe cushion or SHGC in ETFE systems it can vary between 0.2 to 0.95 using frits^[5] and for further info about SHGC in ETFE refer to^[8]

Applications

The Eden Project, Cornwall, UK. Biomes are constructed with ETFE cushions.

ETFE roof at Manchester Piccadilly station, Manchester, UK

ETFE was developed by DuPont in the 1970s initially as a lightweight, heat resistant film in the aerospace industry.^[9] From its development it was largely used infrequently in agricultural and architectural projects.^[9] ETFE's first large-scale use architecturally came in 2001 at the Eden Project where ETFE was selected as it can be printed and layered to control solar conditions and because it was found to have a low friction coefficient, which saves on maintenance as dust and dirt do not stick.^[9]

An example of its use is as pneumatic panels to cover the outside of the football stadium Allianz Arena or the Beijing National Aquatics Centre (a.k.a. the Water Cube of the 2008 Olympics) – the world's largest structure made of ETFE film (laminate). The panels of the Eden Project are also made from ETFE, and the Tropical Islands have a 20,000 m² window made from this translucent material.

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. Commercially deployed brand names of ETFE include Tefzel by DuPont, Fluon by Asahi Glass Company, Neoflon ETFE by Daikin, and Texlon by Vector Foiltec. Sumitomo Electric developed an aluminium-ETFE composite marketed as Sumiflon-E (スミフロンE).^[10] Additionally, now a day the commercial use of architectural ETFE as skylight or facade materials has become very popular all over the world not only in Europe, in middle east for instance many shopping malls, sports and cultural mega venues developments has utilized ETFE for example recent huge greenhouse park development in Abu Dhabi (Mawasem Park – Green House – Abu Dhabi House) managed by Fabrix360 ETFE expert^[11]

Due to its high temperature resistance ETFE is also used in film mode as a mold-release film.^[12] 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.