{
  "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.\n",
  "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": "",
    "designations": [],
    "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,
      "bound": "exact",
      "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",
      "source_detail": {
        "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)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density used for the flown ETFE film (NASA erosion-yield calculation)",
      "value": 1.7397,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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)"
      }
    },
    {
      "benchmark": "density",
      "label": "Specific gravity (Daikin NEOFLON ETFE EP-521, representative)",
      "value": 1.74,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "density",
      "label": "Density (Goodfellow ETFE film listing)",
      "value": 1.7,
      "bound": "exact",
      "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 )\"",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point (Daikin NEOFLON ETFE EP-521, representative)",
      "value": 265,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point range (Daikin safety data sheet, EP-521 grade)",
      "value": 210,
      "value_high": 230,
      "bound": "exact",
      "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",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "melt_flow_rate",
      "label": "Melt flow rate (Daikin NEOFLON ETFE EP-521)",
      "value": 11,
      "value_high": 13,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength (Daikin NEOFLON ETFE EP-521, representative)",
      "value": 40,
      "value_high": 55,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength (ETFE film listing)",
      "value": 28,
      "value_high": 48,
      "bound": "exact",
      "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 )\"",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, unaged longitudinal specimen (ETFE Tefzel PV3221)",
      "value": 60.38,
      "bound": "exact",
      "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",
      "source_detail": {
        "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)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Elastic modulus, unaged longitudinal specimen (ETFE Tefzel PV3221)",
      "value": 1075.38,
      "bound": "exact",
      "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",
      "source_detail": {
        "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)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break (Daikin NEOFLON ETFE EP-521, representative)",
      "value": 300,
      "value_high": 600,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break (ETFE film listing)",
      "value": 250,
      "value_high": 350,
      "bound": "exact",
      "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( % )\"",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break, unaged longitudinal specimen (ETFE Tefzel PV3221)",
      "value": 310.74,
      "bound": "exact",
      "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",
      "source_detail": {
        "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)"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Dielectric constant at 1 MHz",
      "value": 2.6,
      "bound": "exact",
      "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\"",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Upper working temperature (ETFE film listing)",
      "value": 150,
      "value_high": 160,
      "bound": "exact",
      "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 )\"",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "crystallinity",
      "label": "Crystallinity after irradiation at 1600 kGy (air, 20 kGy/h)",
      "value": 12.6,
      "bound": "exact",
      "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))",
      "source_detail": {
        "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"
      }
    }
  ],
  "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)"
    }
  ],
  "media": [],
  "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
    }
  ],
  "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."
  ],
  "story": {
    "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",
        "line": "On the MISSE 2 flight, ETFE eroded at 9.61e-25 cm3/atom, about three times more slowly than Kapton H.",
        "benchmark": "atomic_oxygen_erosion_yield",
        "scope": "material",
        "value": "9.61e-25 cm3/atom"
      },
      {
        "label": "Stiffness",
        "line": "Unaged longitudinal film specimens had an elastic modulus of 1075.38 MPa in one tensile study.",
        "benchmark": "elastic_modulus",
        "scope": "material",
        "value": "1075 MPa"
      },
      {
        "label": "Melting",
        "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.",
        "benchmark": "melting_point",
        "scope": "material",
        "value": "265 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",
        "scope": "material"
      },
      {
        "label": "Atomic oxygen erosion yield (MISSE 2)",
        "benchmark": "atomic_oxygen_erosion_yield",
        "scope": "material"
      },
      {
        "label": "Upper service temperature",
        "benchmark": "max_service_temp",
        "scope": "material"
      }
    ],
    "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.",
    "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",
        "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."
          }
        ],
        "level": 0,
        "verdict": "Not classified under CLP"
      },
      {
        "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."
          }
        ]
      }
    ]
  },
  "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."
  },
  "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"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/etfe-tefzel/"
}