spore: profile id: etfe-tefzel spore_version: 0.2 family: fluoropolymers name: Ethylene-tetrafluoroethylene copolymer abbreviation: ETFE role: melt-processible fluoropolymer for wire insulation, film and lined equipment category: polymers type: fluoropolymers summary: | ETFE (Tefzel, Neoflon, Fluon) is a copolymer of ethylene and tetrafluoroethylene. On the MISSE 2 flight, mounted outside the International Space Station for 3.95 years, it eroded under atomic oxygen at 9.61e-25 cm3/atom, about 3 times slower than Kapton H (3.00e-24 cm3/atom) and about 7 times faster than PTFE (1.42e-25 cm3/atom). Its manufacturer lists a melting point of 265 C and a service limit of 150 to 160 C. Radiation is the known weak point: a Japanese study found its elongation falls sharply above about 400 kGy in air, and its crystallinity drops from 43.2% to 12.6% by 1600 kGy. best_for: Melt-processible, tough fluoropolymer insulation and film that resists atomic oxygen better than Kapton H and most hydrocarbon polymers weakest_at: Ionizing radiation in air (elongation falls sharply above about 400 kGy) and continuous service above about 160 C identity: formula: Poly(ethene-co-tetrafluoroethene), repeat unit C4H4F4 (ethylene C2H4 plus tetrafluoroethylene C2F4) cas: '' source: banks2008 where: Table IV (repeat-unit formula C4H4F4, atomic mass 128.0676 g/mole); monomer names from Wikipedia (poly(ethene-co-tetrafluoroethene)) tags: environments: - low-earth-orbit stresses: - atomic-oxygen - uv - total-radiation-dose - thermal-cycling - vacuum-and-outgassing applications: - electronics-and-chips - structures properties: - benchmark: atomic_oxygen_erosion_yield label: Atomic oxygen erosion yield, MISSE 2 PEACE polymers (flight) value: 9.61e-25 unit: cm3/atom scope: material conditions: experiment: MISSE 2 PEACE polymers, exterior of the International Space Station exposure: 3.95 yr in low Earth orbit, 16 August 2001 to 30 July 2005 fluence: 8.43e21 atoms/cm2 comparison: Kapton H polyimide measured 3.00e-24 cm3/atom, PTFE 1.42e-25 cm3/atom, FEP 2.00e-25 cm3/atom, in the same table method: Mass-loss erosion yield from the flown samples, as compiled in the NASA report status: flight note: The report's predictive tool gave 1.39e-24 cm3/atom for ETFE (Table VII), about 45% above the measured value. source: banks2008 where: Table I (MISSE 2 PEACE polymers erosion yield data); Table VII; Section 2.1 for exposure - benchmark: density label: Density used for the flown ETFE film (NASA erosion-yield calculation) value: 1.7397 unit: g/cm3 scope: material conditions: sample: ETFE (Tefzel) film flown on MISSE 2 PEACE polymers ash_fraction: '5.34e-3' method: Density value listed in the NASA report for the erosion-yield calculation status: ground source: banks2008 where: Table II (MISSE 2 PEACE polymers density and fractional ash content) - benchmark: density label: Specific gravity (Daikin NEOFLON ETFE EP-521, representative) value: 1.74 unit: '-' scope: material conditions: grade: NEOFLON ETFE EP-521 (Daikin) test_standard: ASTM D 792 method: Representative value printed in the manufacturer technical datasheet; the sheet says the values are not guaranteed status: ground source: daikin-tds-ep521 where: General physical properties table (Specific Gravity) - benchmark: density label: Density (Goodfellow ETFE film listing) value: 1.7 unit: g/cm3 scope: material conditions: form: ETFE film, reseller listing method: Value printed in a film supplier listing status: ground source: goodfellow-etfe where: Property table, row "Density( gcm-3 )" - benchmark: melting_point label: Melting point (Daikin NEOFLON ETFE EP-521, representative) value: 265 unit: C scope: material conditions: grade: NEOFLON ETFE EP-521 (Daikin) test_standard: ASTM D 3159 method: Representative value printed in the manufacturer technical datasheet; the sheet says the values are not guaranteed status: ground source: daikin-tds-ep521 where: General physical properties table (Melting Point) - benchmark: melting_point label: Melting point range (Daikin safety data sheet, EP-521 grade) value: 210 value_high: 230 unit: C scope: material conditions: grade: NEOFLON ETFE EP-521 (Daikin) method: Range printed in the manufacturer safety data sheet, section 9 status: ground note: The datasheet for the same grade gives 265 C, so the two Daikin documents disagree by about 35 C. source: daikin-sds-ep521 where: Section 9, Melting point/freezing point - benchmark: melt_flow_rate label: Melt flow rate (Daikin NEOFLON ETFE EP-521) value: 11 value_high: 13 unit: g/10min scope: material conditions: test_standard: ASTM D 3159 method: Representative value printed in the manufacturer technical datasheet status: ground source: daikin-tds-ep521 where: General physical properties table (MFR) - benchmark: ultimate_tensile_strength label: Tensile strength (Daikin NEOFLON ETFE EP-521, representative) value: 40 value_high: 55 unit: MPa scope: material conditions: test_standard: ASTM D 638 method: Representative range printed in the manufacturer technical datasheet status: ground note: The Goodfellow listing gives a lower range, 28 to 48 MPa. source: daikin-tds-ep521 where: General physical properties table (Tensile strength) - benchmark: ultimate_tensile_strength label: Tensile strength (ETFE film listing) value: 28 value_high: 48 unit: MPa scope: material conditions: form: ETFE film, reseller listing method: Range printed in a film supplier listing status: ground source: goodfellow-etfe where: Property table, row "Tensile strength( MPa )" - benchmark: ultimate_tensile_strength label: Tensile strength, unaged longitudinal specimen (ETFE Tefzel PV3221) value: 60.38 unit: MPa scope: material conditions: grade: Tefzel PV3221 film specimen: longitudinal (L) specimen, not aged method: Mean from tensile tests (standard deviation 7.91 MPa) status: ground source: bracciale2022 where: Table 2, Section 3.1 - benchmark: elastic_modulus label: Elastic modulus, unaged longitudinal specimen (ETFE Tefzel PV3221) value: 1075.38 unit: MPa scope: material conditions: grade: Tefzel PV3221 film specimen: longitudinal (L) specimen, not aged method: Mean from tensile tests (standard deviation 43.51 MPa) status: ground source: bracciale2022 where: Table 2, Section 3.1 - benchmark: elongation label: Elongation at break (Daikin NEOFLON ETFE EP-521, representative) value: 300 value_high: 600 unit: '%' scope: material conditions: test_standard: ASTM D 638 method: Representative range printed in the manufacturer technical datasheet status: ground note: The Goodfellow listing gives 250 to 350 percent, so the two supplier ranges disagree. source: daikin-tds-ep521 where: General physical properties table (Elongation) - benchmark: elongation label: Elongation at break (ETFE film listing) value: 250 value_high: 350 unit: '%' scope: material conditions: form: ETFE film, reseller listing method: Range printed in a film supplier listing status: ground source: goodfellow-etfe where: Property table, row "Elongation at break( % )" - benchmark: elongation label: Elongation at break, unaged longitudinal specimen (ETFE Tefzel PV3221) value: 310.74 unit: '%' scope: material conditions: grade: Tefzel PV3221 film specimen: longitudinal (L) specimen, not aged method: Mean from tensile tests (standard deviation 45.55 percent) status: ground source: bracciale2022 where: Table 2, Section 3.1 - benchmark: dielectric_constant label: Dielectric constant at 1 MHz value: 2.6 unit: dimensionless scope: material conditions: frequency: 1 MHz method: Value printed in a film supplier property table status: ground source: goodfellow-etfe where: Property table, row "Dielectric constant @1MHz" - benchmark: max_service_temp label: Upper working temperature (ETFE film listing) value: 150 value_high: 160 unit: C scope: material conditions: basis: upper working temperature method: Range printed in the thermal properties table of a film supplier listing status: ground note: The same page's key-features text gives 150 to 200 C, a wider range than its table. source: goodfellow-etfe where: Thermal Properties table, row "Upper working temperature( C )" - benchmark: crystallinity label: Crystallinity after irradiation at 1600 kGy (air, 20 kGy/h) value: 12.6 unit: '%' scope: material conditions: dose: 0 to 1600 kGy electron beam dose_rate: 20 kGy/h atmosphere: air method: Crystallinity from the abstract of a radiation-processing study status: ground note: The unirradiated baseline in the same abstract is 43.2 percent. The abstract gives no per-dose elongation values; it says elongation decreased slowly from 0 to 200 kGy and dropped sharply above 400 kGy. source: sinap2015 where: English abstract (Journal of Radiation Research and Radiation Processing, 2015, 33(6)) corrosion: - environment: Atomic oxygen in low Earth orbit headline: ETFE eroded about three times more slowly than Kapton H on the ISS, but several times faster than PTFE. effect: Measured erosion yields from MISSE 2 were 9.61e-25 cm3/atom for ETFE, 3.00e-24 for Kapton H, 2.00e-25 for FEP and 1.42e-25 for PTFE. The NASA predictive tool overestimated ETFE by about 45 percent (1.39e-24). rating: moderate conditions: exposure: 3.95 yr on the ISS exterior, fluence 8.43e21 atoms/cm2 source: banks2008 where: Table I; Table VII - environment: Ultraviolet A light with humidity (accelerated ageing) headline: Accelerated UV-A ageing with condensation was run on ETFE film, but the study reports no total dose in hours or J/m2. effect: Bracciale et al. aged ETFE and PFA films in cycles of 6 h UV-A (300 to 400 nm, peak 365 nm, 5.2 W/m2) plus 3 h of condensation at 25 C and 80 to 90 percent humidity, and reported that ETFE kept a higher elastic modulus and tear energy than PFA after ageing. The article states no total exposure time, so the aged values are not quoted here. rating: low conditions: temperature: 25 C humidity: 80 to 90 percent relative humidity cycle: 6 h UV-A plus 3 h condensation, 6 cycles source: bracciale2022 where: Section 2.2 (ageing conditions), Section 3.2 (Table 5) - environment: Ionizing radiation in air headline: ETFE elongation holds up at low dose and falls sharply above about 400 kGy in air. effect: Electron-beam irradiation at 20 kGy/h in air lowered crystallinity from 43.2 to 12.6 percent by 1600 kGy and melting point from 261.3 to 233.3 C. The abstract says elongation decreased slowly over 0 to 200 kGy and dropped sharply above 400 kGy, and that tensile strength followed the same pattern. rating: severe conditions: dose_rate: 20 kGy/h atmosphere: air source_type: electron beam source: sinap2015 where: English abstract risks: hazards: - text: The Daikin safety data sheet for NEOFLON ETFE EP-521 says the substance is not classified under Regulation (EC) No 1272/2008 (CLP) and has no label elements. Acute-toxicity data are not available, and the other hazard classes report that the classification criteria are not met. ghs: [] source: daikin-sds-ep521 where: Sections 2.1 and 11.1 failure_risks: - mode: Thermal decomposition during processing or overheating trigger: Overheating the molten polymer consequence: The safety data sheet says decomposition can give particulate matter and extremely toxic or corrosive fumes, and that molten product should be cooled quickly with cold water. severity: moderate source: daikin-sds-ep521 where: Sections 5, 7 and 10.6 - mode: Loss of ductility under ionizing radiation trigger: Electron-beam dose above about 400 kGy in air consequence: Elongation drops sharply, and the crystallinity and melting point fall with dose. severity: moderate source: sinap2015 where: English abstract side_effects: [] handling: - text: Keep molten product from overheating, and cool any molten material rapidly with cold water, as the safety data sheet advises. source: daikin-sds-ep521 where: Sections 7 and 10 mitigations: [] uses: - application: electronics-and-chips device: Wire and cable insulation (aerospace, automotive and appliance) example: The manufacturer lists wire and cable for aerospace, automotive and appliance use among ETFE's main markets, and says the grade has good radiation resistance because of its ethylene comonomer. source: daikin-tds-ep521 where: Introduction and bullet list - application: structures device: ETFE film in building envelopes example: Commercial ETFE film is sold under the names Texlon (Vector Foiltec) and Sumiflon-E (Sumitomo Electric, an aluminium-ETFE composite). source: wiki-etfe where: Trade names list supply: - subject: Fluorine feedstock (fluorspar, the source of hydrogen fluoride for fluoropolymer monomers) producers: - country: China share_percent: 60 year: 2025 - country: Mongolia share_percent: 15 year: 2025 critical_lists: [] recycling: Not stated in the USGS fluorspar chapter that was fetched. substitutes: [] source: usgs-mcs2026-fluorspar where: World Mine Production and Reserves table (2025 column; China 6,000 and Mongolia 1,500 of a printed world total of 10,000 thousand t, shares calculated by Space Mushroom); Domestic Production and Use (fluorspar feeds anhydrous hydrogen fluoride) gaps: - 'No ETFE hazard row found on PubChem: the PubChem pages returned a browser check and the REST name lookup found no record for ETFE.' - The USGS fluorspar chapter fetched here does not list fluorspar on the critical-mineral lists; the EU and USGS list status for fluorspar is not confirmed in this run. - No vacuum outgassing (TML, CVCM) value for ETFE was found in this run; the RP-1124 and NASA outgassing compilations were not searched for ETFE. - No ETFE-specific UV or atomic oxygen erosion study with a dose in hours or J/m2 was found; the Bracciale UV-A study gives conditions but no total dose. - The Chemours and Plastics International datasheets were blocked (HTTP 403 or 404); manufacturer values come from Daikin and a film listing. - No gamma-ray dose series for ETFE elongation was found; the Tefzel datasheet statement about electron beam versus gamma was seen only in a search snippet and is not used as a value. - The Daikin safety data sheet covers the EP-521 grade; coating-powder grades (EPW series) carry a different classification through N-methyl-2-pyrrolidone and are not used here. sources: banks2008: title: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit id: NASA/TM-2008-215490 (Banks, Backus and de Groh, December 2008), NTRS 20090011780 url: https://ntrs.nasa.gov/citations/20090011780 year: 2008 kind: report license: public domain (NASA) daikin-tds-ep521: title: NEOFLON ETFE EP-521 Technical Datasheet (Daikin Industries, version 01, March 2018) id: tds-ep-521-E_ver01_Mar_2018 url: https://www.daikinchemicals.com/library/pb_common/pdf/tds/Fluoropolymers/NEOFLON_ETFE/tds-ep-521-E_ver01_Mar_2018.pdf year: 2018 kind: datasheet license: manufacturer document, linked not reproduced daikin-sds-ep521: title: Safety Data Sheet, NEOFLON ETFE EP-521 (Daikin Chemicals) id: sds-EP521-E_20230308 url: https://www.daikinchemicals.com/library/pb_common/pdf/sds/Fluoropolymer/ETFE_EP-series/sds-EP521-E_20230308.pdf year: 2023 kind: datasheet license: supplier document, linked not reproduced goodfellow-etfe: title: Goodfellow ETFE film property listing id: Goodfellow Cambridge, ETFE film group url: https://www.goodfellow.com/usa/etfe-film-group year: 2026 kind: web license: reseller page, linked not reproduced bracciale2022: title: Effect of Accelerated UV Ageing on ETFE and PFA Films (Bracciale, Capasso, Sarasini, Tirillo, Santarelli) id: doi:10.3390/polym14050912 (Polymers 14(5), 912, 2022, PMC8912537) url: https://pmc.ncbi.nlm.nih.gov/articles/PMC8912537/ year: 2022 kind: paper license: CC BY 4.0 (as listed by PMC) sinap2015: title: Radiation effects on ETFE in air (Journal of Radiation Research and Radiation Processing, 33(6)) id: doi:10.11889/j.1000-3436.2015.rrj.33.060301 url: https://www.fs.sinap.ac.cn/zh/article/doi/10.11889/j.1000-3436.2015.rrj.33.060301/ year: 2015 kind: paper license: journal abstract, linked not reproduced usgs-mcs2026-fluorspar: title: Mineral Commodity Summaries 2026, Fluorspar id: USGS MCS 2026, February 2026 url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf year: 2026 kind: report license: public domain (USGS) wiki-etfe: title: Ethylene tetrafluoroethylene (Wikipedia) id: Wikipedia, Ethylene_tetrafluoroethylene url: https://en.wikipedia.org/wiki/Ethylene_tetrafluoroethylene year: 2026 kind: web license: CC BY-SA 4.0 documents: - title: NASA/TM-2008-215490, Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit type: report url: https://ntrs.nasa.gov/citations/20090011780 year: 2008 - title: Daikin NEOFLON ETFE EP-521 technical datasheet type: datasheet url: https://www.daikinchemicals.com/library/pb_common/pdf/tds/Fluoropolymers/NEOFLON_ETFE/tds-ep-521-E_ver01_Mar_2018.pdf year: 2018 - title: Daikin NEOFLON ETFE EP-521 safety data sheet type: sds url: https://www.daikinchemicals.com/library/pb_common/pdf/sds/Fluoropolymer/ETFE_EP-series/sds-EP521-E_20230308.pdf year: 2023 - title: Bracciale et al., Polymers 14(5), 912 (open access) type: paper url: https://pmc.ncbi.nlm.nih.gov/articles/PMC8912537/ year: 2022 - title: USGS Mineral Commodity Summaries 2026, Fluorspar type: report url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf year: 2026 license: CC-BY-4.0 updated: '2026-10-20' review: status: draft method: assistant checked_values: 17 unreachable: 4 caveats: 3 note: Read in one run by an AI assistant on 2026-10-20 from fetched pages and downloaded PDFs. Values copied as printed; ranges kept as printed. story: recipe: line: ETFE is a copolymer of ethylene (C2H4) and tetrafluoroethylene (C2F4). Its repeat unit is C4H4F4, with a molar mass of 128.0676 g/mole in the NASA table. parts: - name: Ethylene symbol: C2H4 role: Comonomer that gives ETFE its toughness and melt processability. The NASA table lists the repeat unit as C4H4F4 (one ethylene and one tetrafluoroethylene unit). - name: Tetrafluoroethylene symbol: C2F4 role: The fluorine-rich comonomer that gives chemical inertness and electrical insulation. risk_groups: - title: For people level: 0 verdict: Not classified under CLP lead: The supplier's safety data sheet for ETFE resin says the substance is not classified and has no label elements. points: - label: The resin line: The Daikin safety data sheet for NEOFLON ETFE EP-521 classifies the substance as not classified under the EU CLP regulation. Its acute-toxicity data are not available. - label: Overheating line: Overheating the molten polymer can produce particulate matter and extremely toxic or corrosive fumes, so the sheet says not to overheat. - title: Handling and processing points: - label: Molten product line: The safety data sheet says to cool molten product rapidly with cold water. - label: Radiation line: Electron-beam dose above about 400 kGy in air sharply reduces elongation. why: ETFE is a melt-processible fluoropolymer that trades some of PTFE's chemical and thermal ceiling for the ability to be extruded, injection moulded and drawn into thin film. The fluorine content gives electrical insulation and resistance to atomic oxygen, and the ethylene units add toughness and melt flow. On the MISSE 2 flight its erosion yield was three times lower than Kapton H. uses: - where: Wire and cable line: The manufacturer lists wire and cable insulation for aerospace, automotive and appliance use as a main market for ETFE, and says the grade has good radiation resistance. - where: Building film line: ETFE film is sold as Texlon (Vector Foiltec) and Sumiflon-E (Sumitomo Electric, an aluminium-ETFE composite). can_do: - label: Atomic oxygen benchmark: atomic_oxygen_erosion_yield value: 9.61e-25 cm3/atom line: On the MISSE 2 flight, ETFE eroded at 9.61e-25 cm3/atom, about three times more slowly than Kapton H. - label: Stiffness benchmark: elastic_modulus value: 1075 MPa line: Unaged longitudinal film specimens had an elastic modulus of 1075.38 MPa in one tensile study. - label: Melting benchmark: melting_point value: 265 C line: The manufacturer's datasheet gives a melting point of 265 C for the EP-521 grade, although its safety data sheet gives 210 to 230 C. compare: ETFE sits between PTFE and the hydrocarbon polymers. Its flown erosion yield is about seven times higher than PTFE and about three times lower than Kapton H. It is melt-processible, which PTFE is not, and it stays usable to about 150 to 160 C, a lower limit than PTFE's. The table compares ETFE with PTFE and Kapton H on three measured rows. compare_rows: - label: Density benchmark: density - label: Atomic oxygen erosion yield (MISSE 2) benchmark: atomic_oxygen_erosion_yield - label: Upper service temperature benchmark: max_service_temp handling: - The resin is not classified under CLP. Keep molten product from overheating. - Cool molten product rapidly with cold water, as the supplier advises. - Expect a sharp loss of elongation after about 400 kGy of electron-beam dose in air. good_for: - Atomic oxygen resistance in LEO. ETFE eroded at 9.61e-25 cm3/atom, about three times more slowly than Kapton H. - Melt-processible insulation and thin film, where PTFE cannot be extruded. watch_out: - Radiation in air. Elongation falls sharply above about 400 kGy. - Service limit near 150 to 160 C for the film listing, lower than PTFE's. - The two Daikin documents for the same grade disagree on melting point (210 to 230 C vs 265 C). verdict: ETFE is a practical fluoropolymer for LEO insulation and film. It erodes more than PTFE and is weaker to ionizing radiation in air, so it is a sound choice where it is shielded or where melt processing matters.