{
  "spore": "profile",
  "id": "fep",
  "spore_version": "0.2",
  "family": "fluoropolymers",
  "name": "Fluorinated ethylene propylene",
  "abbreviation": "FEP",
  "role": "melt-processible fluoropolymer for wire coating, linings and low-outgassing films",
  "category": "polymers",
  "type": "fluoropolymers",
  "summary": "FEP is a melt-processible copolymer of tetrafluoroethylene and hexafluoropropylene, sold by DuPont as Teflon FEP and by Daikin as NEOFLON FEP. It melts near 255 degC by ASTM D 3418 and is almost chemically inert. On the MISSE 2 flight it eroded under atomic oxygen at 2.00e-25 cm3/atom, and Hubble's retrieved FEP lost most of its stretch after long exposure in low Earth orbit.",
  "best_for": "A chemically inert, electrically insulating and low-outgassing fluoropolymer that can be melt-processed into thin films, coatings and tubing.",
  "weakest_at": "Mechanical strength and ductility after long orbital exposure (Hubble retrieved specimens dropped to 0 to 25 percent elongation), and releasing hydrogen fluoride when processed above 250 degC.",
  "identity": {
    "formula": "Copolymer of tetrafluoroethylene and hexafluoropropylene, (-CF2-CF2-)n units with -CF2-CF(CF3)- units; CAS 25067-11-2",
    "cas": "25067-11-2",
    "designations": [],
    "source": "daikin-fep-stewardship",
    "where": "Chemical Name and CAS Registry Number table; composition from Wikipedia FEP lead paragraph (copolymer of hexafluoropropylene and tetrafluoroethylene)"
  },
  "tags": {
    "environments": [
      "low-earth-orbit"
    ],
    "stresses": [
      "atomic-oxygen",
      "total-radiation-dose",
      "thermal-cycling",
      "vacuum-and-outgassing"
    ],
    "applications": [
      "electronics-and-chips",
      "propulsion-and-tanks"
    ]
  },
  "properties": [
    {
      "benchmark": "atomic_oxygen_erosion_yield",
      "label": "Atomic oxygen erosion yield, MISSE 2 flight",
      "value": 2e-25,
      "bound": "exact",
      "unit": "cm3/atom",
      "scope": "material",
      "conditions": {
        "environment": "low Earth orbit, ISS MISSE 2 PEACE Polymers tray",
        "fluence": "8.43e21 atoms/cm2 (4 year exposure)",
        "unit_in_source": "cm3/atom"
      },
      "method": "Value printed in NASA Table I (MISSE 2 PEACE Polymers erosion yield data) as the measured MISSE 2 erosion yield; the paper cites refs 11 and 12 for the data",
      "status": "flight",
      "source": "nasa-ao-tool",
      "where": "Table I, row Fluorinated ethylene propylene (FEP), column erosion yield",
      "source_detail": {
        "title": "Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit",
        "id": "NASA/TM-2008-215490",
        "url": "https://ntrs.nasa.gov/api/citations/20090011780/downloads/20090011780.pdf",
        "year": 2008,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density (MISSE 2 sample, ref 12)",
      "value": 2.1443,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "sample": "MISSE 2 PEACE Polymers film"
      },
      "method": "Density listed in NASA Table II (MISSE 2 PEACE Polymers density and fractional ash content), column Density, ref. 12",
      "status": "ground",
      "source": "nasa-ao-tool",
      "where": "Table II, row Fluorinated ethylene propylene (FEP), Density column",
      "source_detail": {
        "title": "Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit",
        "id": "NASA/TM-2008-215490",
        "url": "https://ntrs.nasa.gov/api/citations/20090011780/downloads/20090011780.pdf",
        "year": 2008,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density (semi-finished FEP, ASTM D 792)",
      "value": 2150,
      "bound": "exact",
      "unit": "kg/m3",
      "scope": "material",
      "conditions": {
        "test_standard": "ASTM D 792"
      },
      "method": "Value printed in the Material Data Center property table for Teflon FEP 9495 (Chemours), Other Properties section",
      "status": "ground",
      "source": "mdc-fep-9495",
      "where": "Other Properties table, row Density",
      "source_detail": {
        "title": "Teflon FEP 9495 property data (Material Data Center, Chemours)",
        "id": "materialdatacenter FEP 9495",
        "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
        "year": 2026,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, Teflon FEP 9495",
      "value": 255,
      "bound": "exact",
      "unit": "degC",
      "scope": "material",
      "conditions": {
        "test_standard": "ASTM D 3418"
      },
      "method": "Value printed in the Material Data Center property table for Teflon FEP 9495 (Chemours), Thermal Properties section",
      "status": "ground",
      "source": "mdc-fep-9495",
      "where": "Thermal Properties table, row Melting Temperature",
      "source_detail": {
        "title": "Teflon FEP 9495 property data (Material Data Center, Chemours)",
        "id": "materialdatacenter FEP 9495",
        "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
        "year": 2026,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point range, NEOFLON FEP NP-40 family",
      "value": 245,
      "value_high": 275,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "NEOFLON FEP NP-40, NP-102, NP-112, NP-1105"
      },
      "method": "Value printed in the Daikin safety data sheet, section 9.1, Melting point/freezing point line",
      "status": "ground",
      "source": "daikin-np40-sds",
      "where": "Section 9.1, Information on basic physical and chemical properties",
      "source_detail": {
        "title": "NEOFLON FEP NP-40, NP-102, NP-112, NP-1105 safety data sheet (Daikin)",
        "id": "Daikin SDS, revision 08.03.2023",
        "url": "https://www.daikinchemicals.com/library/pb_common/pdf/sds/Fluoropolymer/FEP_NP-series/sds-np-40-E_20260723.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum operating temperature",
      "value": 204,
      "bound": "exact",
      "unit": "degC",
      "scope": "material",
      "conditions": {
        "basis": "value in the infobox of the Wikipedia article"
      },
      "method": "Value printed in the infobox of the Wikipedia FEP article; it is a secondary summary, not a datasheet value",
      "status": "ground",
      "source": "wiki-fep",
      "where": "Infobox, row Maximum operating temperature",
      "source_detail": {
        "title": "Fluorinated ethylene propylene (Wikipedia)",
        "id": "Wikipedia, en",
        "url": "https://en.wikipedia.org/wiki/Fluorinated_ethylene_propylene",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength at break, Teflon FEP 9495",
      "value": 20,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "test_standard": "ASTM D 638"
      },
      "method": "Value printed in the Material Data Center property table for Teflon FEP 9495, Mechanical Properties section",
      "status": "ground",
      "source": "mdc-fep-9495",
      "where": "Mechanical Properties table, row Tensile Strength",
      "source_detail": {
        "title": "Teflon FEP 9495 property data (Material Data Center, Chemours)",
        "id": "materialdatacenter FEP 9495",
        "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
        "year": 2026,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break, Teflon FEP 9495",
      "value": 300,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "test_standard": "ASTM D 638"
      },
      "method": "Value printed in the Material Data Center property table for Teflon FEP 9495, Mechanical Properties section",
      "status": "ground",
      "source": "mdc-fep-9495",
      "where": "Mechanical Properties table, row Elongation at Break",
      "source_detail": {
        "title": "Teflon FEP 9495 property data (Material Data Center, Chemours)",
        "id": "materialdatacenter FEP 9495",
        "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
        "year": 2026,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break, pristine FEP (Hubble test set)",
      "value": 340,
      "value_high": 390,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "sample": "pristine FEP specimens, Hubble Space Telescope test set (three specimens)"
      },
      "method": "Value printed in NASA Table 3 (summary of strength test results), pristine rows, elongation column",
      "status": "ground",
      "source": "townsend-hst-fep",
      "where": "Table 3, pristine rows, Elongation (%) column",
      "source_detail": {
        "title": "On-Orbit Teflon FEP Degradation (Townsend and Hansen, NASA GSFC)",
        "id": "NTRS 19990040483",
        "url": "https://ntrs.nasa.gov/api/citations/19990040483/downloads/19990040483.pdf",
        "year": 1999,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength, pristine FEP (Hubble test set)",
      "value": 13.8,
      "value_high": 14.3,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "sample": "pristine FEP specimens, Hubble Space Telescope test set"
      },
      "method": "Value printed in NASA Table 3, pristine rows, first (yield) strength column; the table header is garbled in the PDF text layer, so the column is read from its position",
      "status": "ground",
      "source": "townsend-hst-fep",
      "where": "Table 3, pristine rows, Yield Strength (MPa) column",
      "source_detail": {
        "title": "On-Orbit Teflon FEP Degradation (Townsend and Hansen, NASA GSFC)",
        "id": "NTRS 19990040483",
        "url": "https://ntrs.nasa.gov/api/citations/19990040483/downloads/19990040483.pdf",
        "year": 1999,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "flexural_modulus",
      "label": "Flexural modulus, Teflon FEP 9495",
      "value": 520,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "test_standard": "ASTM D 790"
      },
      "method": "Value printed in the Material Data Center property table for Teflon FEP 9495, Mechanical Properties section",
      "status": "ground",
      "source": "mdc-fep-9495",
      "where": "Mechanical Properties table, row Flexural Modulus",
      "source_detail": {
        "title": "Teflon FEP 9495 property data (Material Data Center, Chemours)",
        "id": "materialdatacenter FEP 9495",
        "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
        "year": 2026,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Dielectric constant at 1 MHz",
      "value": 2.03,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "1 MHz",
        "test_standard": "ASTM D 150"
      },
      "method": "Value printed in the Material Data Center property table for Teflon FEP 9495, Electrical Properties section",
      "status": "ground",
      "source": "mdc-fep-9495",
      "where": "Electrical Properties table, row Dielectric Constant, 1 MHz",
      "source_detail": {
        "title": "Teflon FEP 9495 property data (Material Data Center, Chemours)",
        "id": "materialdatacenter FEP 9495",
        "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
        "year": 2026,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "dielectric_strength",
      "label": "Dielectric strength, short time",
      "value": 80,
      "bound": "exact",
      "unit": "kV/mm",
      "scope": "material",
      "conditions": {
        "test_standard": "ASTM D 149",
        "mode": "short time"
      },
      "method": "Value printed in the Material Data Center property table for Teflon FEP 9495, Electrical Properties section",
      "status": "ground",
      "source": "mdc-fep-9495",
      "where": "Electrical Properties table, row Dielectric Strength, Short Time",
      "source_detail": {
        "title": "Teflon FEP 9495 property data (Material Data Center, Chemours)",
        "id": "materialdatacenter FEP 9495",
        "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
        "year": 2026,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "dissipation_factor",
      "label": "Dissipation factor at 1 MHz",
      "value": 0.0006,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "1 MHz",
        "test_standard": "ASTM D 150"
      },
      "method": "Value printed in the Material Data Center property table for Teflon FEP 9495, Electrical Properties section",
      "status": "ground",
      "source": "mdc-fep-9495",
      "where": "Electrical Properties table, row Dissipation Factor, 1 MHz",
      "source_detail": {
        "title": "Teflon FEP 9495 property data (Material Data Center, Chemours)",
        "id": "materialdatacenter FEP 9495",
        "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
        "year": 2026,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "moisture_absorption",
      "label": "Water absorption, 24 hour",
      "value": 0.01,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "test_standard": "ASTM D 570",
        "time": "24 hours"
      },
      "method": "Value printed in the Material Data Center property table for Teflon FEP 9495, Other Properties section",
      "status": "ground",
      "source": "mdc-fep-9495",
      "where": "Other Properties table, row Water Absorption, 24hr",
      "source_detail": {
        "title": "Teflon FEP 9495 property data (Material Data Center, Chemours)",
        "id": "materialdatacenter FEP 9495",
        "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
        "year": 2026,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "limiting_oxygen_index",
      "label": "Limiting oxygen index",
      "value": 95,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "test_standard": "ASTM D 2863"
      },
      "method": "Value printed in the Material Data Center property table for Teflon FEP 9495, Thermal Properties section",
      "status": "ground",
      "source": "mdc-fep-9495",
      "where": "Thermal Properties table, row Limiting Oxygen Index",
      "source_detail": {
        "title": "Teflon FEP 9495 property data (Material Data Center, Chemours)",
        "id": "materialdatacenter FEP 9495",
        "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
        "year": 2026,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    },
    {
      "benchmark": "melt_flow_index",
      "label": "Melt flow index",
      "value": 30,
      "bound": "exact",
      "unit": "g/10min",
      "scope": "material",
      "conditions": {
        "temperature": "372 degC",
        "load": "5 kg",
        "test_standard": "ASTM D 2116"
      },
      "method": "Value printed in the Material Data Center property table for Teflon FEP 9495, Processing section",
      "status": "ground",
      "source": "mdc-fep-9495",
      "where": "Processing/Physical table, row Melt Flow Index, MFI",
      "source_detail": {
        "title": "Teflon FEP 9495 property data (Material Data Center, Chemours)",
        "id": "materialdatacenter FEP 9495",
        "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
        "year": 2026,
        "kind": "datasheet",
        "license": "cited, not reproduced"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Atomic oxygen in low Earth orbit (MISSE 2, about 4 years)",
      "headline": "FEP erodes under atomic oxygen, but more slowly than most polymers on the MISSE 2 tray.",
      "effect": "Measured erosion yield of 2.00e-25 cm3/atom, printed in the same table as the predicted values for 40 polymers.",
      "rating": "unknown",
      "conditions": {
        "fluence": "8.43e21 atoms/cm2"
      },
      "source": "nasa-ao-tool",
      "where": "Table I, FEP row"
    },
    {
      "environment": "Hubble Space Telescope, long-duration exposure in low Earth orbit (outer MLI layer)",
      "headline": "Retrieved FEP lost most of its stretch and became brittle, with cracks through the thickness.",
      "effect": "The retrieved specimens reached 0 percent elongation in the SM2 LS group, against 340 to 390 percent for pristine FEP; the report attributes the damage to thermal cycling and deep-layer electron and proton radiation.",
      "rating": "unknown",
      "conditions": {
        "exposure": "long-duration exposure on Hubble, retrieved on the SM2 servicing mission"
      },
      "source": "townsend-hst-fep",
      "where": "Section on tensile test results, Table 3"
    },
    {
      "environment": "Reactive chemicals and high temperature",
      "headline": "FEP is inert to most chemicals, but elemental fluorine, molten alkali metals and chlorine tetrafluoride attack it.",
      "effect": "Daikin says FEP is completely inert to attack by most chemicals except at high temperature, and is susceptible to high-pressure elemental fluorine gas, molten alkali metals and chlorine tetrafluoride.",
      "rating": "unknown",
      "conditions": {
        "temperature": "high temperature"
      },
      "source": "daikin-fep-stewardship",
      "where": "Physical and Chemical Properties paragraph"
    },
    {
      "environment": "Heating during processing or fire",
      "headline": "Above 250 degC FEP gives off hydrogen fluoride and other toxic fluorinated compounds.",
      "effect": "Daikin states that hydrogen fluoride and other toxic fluorinated compounds may be produced above 250 degC, and the SDS warns that toxic gases form during heating or in fire.",
      "rating": "unknown",
      "conditions": {
        "temperature": "above 250 degC"
      },
      "source": "daikin-fep-stewardship",
      "where": "Exposure Effects of Decomposition Products paragraph"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "The FEP resin is not classified under the CLP regulation and has no GHS pictograms or hazard statements in the Daikin SDS.",
        "ghs": [],
        "source": "daikin-np40-sds",
        "where": "Section 2.1 Classification, and Section 2 hazard statements Not applicable"
      },
      {
        "text": "Heating above 250 degC or fire releases hydrogen fluoride and other toxic fluorinated gases, which can cause serious lung irritation.",
        "ghs": [],
        "source": "daikin-fep-stewardship",
        "where": "Exposure Effects of Decomposition Products paragraph"
      }
    ],
    "failure_risks": [
      {
        "mode": "Long-duration exposure to space, with thermal cycling and radiation,…",
        "consequence": "Long-duration exposure to space, with thermal cycling and radiation, embrittles the film and cracks it, as seen on Hubble.",
        "source": "townsend-hst-fep",
        "where": "Section on tensile test results, Table 3"
      }
    ],
    "side_effects": [
      {
        "text": "Excessive airborne powder can irritate the eyes, skin and upper airways, and smoking near the material can expose smokers to toxic gases.",
        "source": "daikin-fep-stewardship",
        "where": "Health and Environmental Effects paragraph"
      }
    ],
    "handling": [
      {
        "text": "Process ovens and equipment in well-ventilated areas, and wear proper PPE; use colorants with heat stability above 400 degC.",
        "source": "daikin-fep-stewardship",
        "where": "Processing Precautions paragraph"
      }
    ],
    "mitigations": [
      {
        "text": "Ventilate processing areas and keep processing below the temperature at which hydrogen fluoride is produced.",
        "source": "daikin-fep-stewardship",
        "where": "Processing Precautions and Exposure Effects paragraphs"
      }
    ]
  },
  "uses": [
    {
      "application": "electronics-and-chips",
      "device": "Wire and cable insulation",
      "example": "Daikin lists wire and cable coating films and sheets as the main use of its FEP molding materials, together with tubes and small parts.",
      "source": "daikin-fep-stewardship",
      "where": "Uses paragraph"
    },
    {
      "application": "propulsion-and-tanks",
      "device": "Pipe and valve linings and sleeves",
      "example": "Daikin lists pipe and valve linings and sleeves among its typical FEP uses, for lining process piping that must resist aggressive chemicals.",
      "source": "daikin-fep-stewardship",
      "where": "Uses paragraph"
    }
  ],
  "supply": [
    {
      "subject": "Fluorspar (CaF2), the mineral feedstock for fluorine chemistry",
      "abundance": "Fluorspar is the mineral source of the hydrogen fluoride used to make fluoropolymers; USGS reports the primary feedstock for fluorine chemicals, including fluoropolymers, is aqueous HF.",
      "producers": [
        {
          "country": "China",
          "year": 2025
        },
        {
          "country": "Mexico",
          "year": 2025
        },
        {
          "country": "Mongolia",
          "year": 2025
        },
        {
          "country": "South Africa",
          "year": 2025
        },
        {
          "country": "Vietnam",
          "year": 2025
        }
      ],
      "critical_lists": [],
      "substitutes": [],
      "source": "usgs-fluorspar-2026",
      "where": "World Mine Production table, 2025 column; world total 10,000 thousand metric tons (rounded)"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit (NASA/TM-2008-215490)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/20090011780/downloads/20090011780.pdf",
      "year": 2008
    },
    {
      "title": "Teflon FEP on-orbit degradation (Townsend and Hansen, NASA GSFC)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/19990040483/downloads/19990040483.pdf",
      "year": 1999
    },
    {
      "title": "NEOFLON FEP NP-40, NP-102, NP-112, NP-1105 safety data sheet (Daikin, revision 08.03.2023)",
      "type": "sds",
      "url": "https://www.daikinchemicals.com/library/pb_common/pdf/sds/Fluoropolymer/FEP_NP-series/sds-np-40-E_20260723.pdf",
      "year": 2023
    },
    {
      "title": "NEOFLON FEP NF Series safety data sheet (Daikin, revision 31.03.2023)",
      "type": "sds",
      "url": "https://www.daikinchemicals.com/library/pb_common/pdf/sds/Fluoropolymer_Films/NEOFLON_FEP_NF_Series_DIL_EN_20260716.pdf",
      "year": 2023
    },
    {
      "title": "Mineral Commodity Summaries 2026: Fluorspar (USGS)",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf",
      "year": 2026
    },
    {
      "title": "Teflon FEP 9495 property table (Material Data Center, Chemours)",
      "type": "datasheet",
      "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
      "year": 2026
    }
  ],
  "gaps": [
    "No ageing or ultraviolet test values for FEP were read in this run; the VUV and X-ray studies found in search were not opened for numbers.",
    "No humid-air or water-vapour corrosion result for FEP found; the water absorption value is the only moisture number.",
    "Atomic weights of C, F and H are not sourced in this run, so recipe parts carry no atomic_weight field.",
    "Monomer share in the FEP copolymer is not read from a source with a number; Wikipedia gives about 5 percent propylene component, which is not used as a value here.",
    "Erosion yield, melt flow index and limiting oxygen index use names that are not in spores/property-canon.yaml; they are listed here as new names.",
    "No PubChem GHS entry was opened; the hazard data rest on the Daikin and SDS documents.",
    "The Interstate Plastics FEP safety sheet returned HTTP 403 and was not read.",
    "No FEP-specific critical-mineral listing; fluorspar is in USGS MCS 2026 but its critical-mineral status is not stated in the page read."
  ],
  "story": {
    "why": "FEP keeps the chemical inertness and insulating behaviour of PTFE but can be melt-processed into thin films, coatings and tubing. On the MISSE 2 flight its atomic oxygen erosion yield was 2.00e-25 cm3/atom, and its dielectric constant at 1 MHz is 2.03.",
    "uses": [
      {
        "where": "Use",
        "line": "Wire and cable insulation, where the low dielectric constant and dissipation factor matter."
      },
      {
        "where": "Use",
        "line": "Pipe and valve linings and sleeves in chemical plants."
      },
      {
        "where": "Use",
        "line": "Thin films for spacecraft thermal blankets, where the MISSE 2 erosion yield and the Hubble embrittlement set the limits."
      }
    ],
    "can_do": [
      {
        "label": "Strength",
        "line": "FEP resists most chemicals, insulates well at high frequency, and melt-processes into thin films. It has a melting point of 255 degC and a 20 MPa tensile strength in the ASTM D 638 test.",
        "scope": "material"
      }
    ],
    "compare": "Among the MISSE 2 polymers FEP erodes slowly under atomic oxygen, at 2.00e-25 cm3/atom. It melts at about 255 degC and can be melt-processed, which PTFE cannot. Its tensile strength of 20 MPa and elongation of 300 percent are modest for a structural role.",
    "compare_rows": [
      {
        "label": "Melting point",
        "benchmark": "melting_point",
        "scope": "material"
      },
      {
        "label": "Tensile strength",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material"
      },
      {
        "label": "Dielectric constant at 1 MHz",
        "benchmark": "dielectric_constant",
        "scope": "material"
      }
    ],
    "handling": [
      "Ventilate ovens and extrusion lines, wear PPE, and keep processing below the temperature at which hydrogen fluoride is produced. Use colorants with heat stability above 400 degC. Keep burning or overheated FEP away from people."
    ],
    "good_for": [
      "Insulating wire and cable jackets, linings for chemical pipework, and low-outgassing films where chemical inertness and atomic oxygen resistance matter."
    ],
    "watch_out": [
      "Long orbital exposure embrittles FEP; the Hubble specimens reached 0 percent elongation. Above 250 degC it releases hydrogen fluoride, and it has low tensile strength for structural loads."
    ],
    "verdict": "FEP is a practical, chemically inert insulator with good atomic oxygen resistance for its class, but its ductility falls off sharply after long exposure to thermal cycling and radiation, so it should be used as a thin, protected layer rather than a structural part.",
    "recipe": {
      "line": "FEP is a copolymer of tetrafluoroethylene and hexafluoropropylene. Its repeat units are CF2-CF2 from the first monomer and CF2-CF(CF3) from the second, with a small fraction of propylene-based units in the chain according to Wikipedia. Daikin and Chemours sell it as a pellet resin, and it is processed by melt extrusion or injection moulding.",
      "parts": [
        {
          "name": "Tetrafluoroethylene",
          "role": "Main backbone monomer; the -CF2-CF2- units give the chemical inertness and low friction of the chain."
        },
        {
          "name": "Hexafluoropropylene",
          "role": "Second monomer; its pendant -CF3 groups break up the crystal structure, so FEP melts about 40 degC lower than PFA according to Wikipedia."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "Workers who melt, extrude or mould FEP, because processing above 250…",
        "points": []
      },
      {
        "title": "Firefighters and anyone handling burning FEP, because fire produces…",
        "points": []
      },
      {
        "title": "Mission planners using FEP outer layers, because thermal cycling and…",
        "points": []
      }
    ]
  },
  "updated": "2026-10-20",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 17,
    "unreachable": 1,
    "caveats": 1,
    "note": "Written from pages fetched in this run: 17 property values, 8 sources. Interstate Plastics sheet returned HTTP 403."
  },
  "sources": {
    "nasa-ao-tool": {
      "title": "Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit",
      "id": "NASA/TM-2008-215490",
      "url": "https://ntrs.nasa.gov/api/citations/20090011780/downloads/20090011780.pdf",
      "year": 2008,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "townsend-hst-fep": {
      "title": "On-Orbit Teflon FEP Degradation (Townsend and Hansen, NASA GSFC)",
      "id": "NTRS 19990040483",
      "url": "https://ntrs.nasa.gov/api/citations/19990040483/downloads/19990040483.pdf",
      "year": 1999,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "daikin-np40-sds": {
      "title": "NEOFLON FEP NP-40, NP-102, NP-112, NP-1105 safety data sheet (Daikin)",
      "id": "Daikin SDS, revision 08.03.2023",
      "url": "https://www.daikinchemicals.com/library/pb_common/pdf/sds/Fluoropolymer/FEP_NP-series/sds-np-40-E_20260723.pdf",
      "year": 2023,
      "kind": "datasheet",
      "license": "cited, not reproduced"
    },
    "daikin-nf-sds": {
      "title": "NEOFLON FEP NF Series safety data sheet (Daikin)",
      "id": "Daikin SDS, revision 31.03.2023",
      "url": "https://www.daikinchemicals.com/library/pb_common/pdf/sds/Fluoropolymer_Films/NEOFLON_FEP_NF_Series_DIL_EN_20260716.pdf",
      "year": 2023,
      "kind": "datasheet",
      "license": "cited, not reproduced"
    },
    "daikin-fep-stewardship": {
      "title": "Daikin-NEOFLON FEP product stewardship summary (env-pss-fep-001)",
      "id": "env-pss-fep-001 Rev. 0",
      "url": "https://www.daikinchemicals.com/library/pb_common/pdf/dai/env-pss-fep-001_Rev.0-002.pdf",
      "year": 2021,
      "kind": "datasheet",
      "license": "cited, not reproduced"
    },
    "usgs-fluorspar-2026": {
      "title": "Mineral Commodity Summaries 2026: Fluorspar (U.S. Geological Survey)",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "mdc-fep-9495": {
      "title": "Teflon FEP 9495 property data (Material Data Center, Chemours)",
      "id": "materialdatacenter FEP 9495",
      "url": "https://www.materialdatacenter.com/ms/en/Teflon/The+Chemours+Company/Teflon™+FEP+9495/6a4f05df/824",
      "year": 2026,
      "kind": "datasheet",
      "license": "cited, not reproduced"
    },
    "wiki-fep": {
      "title": "Fluorinated ethylene propylene (Wikipedia)",
      "id": "Wikipedia, en",
      "url": "https://en.wikipedia.org/wiki/Fluorinated_ethylene_propylene",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/fep/"
}