{
  "spore": "profile",
  "id": "ctfe-kel-f",
  "spore_version": "0.2",
  "family": "fluoropolymers",
  "name": "Polychlorotrifluoroethylene",
  "abbreviation": "PCTFE (CTFE, Kel-F)",
  "role": "chemically inert, moisture-barrier fluoropolymer with low gas absorption at cryogenic temperature",
  "category": "polymers",
  "type": "fluoropolymers",
  "summary": "PCTFE (sold as Kel-F) is a fluoropolymer in which one fluorine on each carbon pair is replaced by chlorine. Its density is 2.1327 g/cm3 and it melts near 210 to 212 degC (Daikin datasheets). On the NASA MISSE 2 flight it eroded under atomic oxygen at 8.31e-25 cm3/atom after 3.95 years, far slower than Kapton H. At 77 K it kept a tensile strength of 127.78 MPa in a liquid-oxygen study, so it is one of the few polymers used for cryogenic seals.\n",
  "best_for": "Cryogenic and liquid-oxygen seals, valve seats and moisture barriers where chemical inertness matters more than stiffness",
  "weakest_at": "Ionizing radiation (it degrades like PTFE) and a low continuous service temperature compared with metals; a valve-seat study also found dimensional instability between 40 and 70 degC",
  "identity": {
    "formula": "(C2ClF3)n, repeat unit -CF2-CFCl-",
    "cas": "9002-83-9",
    "designations": [],
    "source": "wiki-pctfe",
    "where": "Infobox and Section 'Properties' of the Polychlorotrifluoroethylene Wikipedia article (CAS 9002-83-9); repeat-unit formula C2ClF3 from the NASA MISSE 2 Table IV (banks2008)"
  },
  "tags": {
    "environments": [
      "low-earth-orbit"
    ],
    "stresses": [
      "atomic-oxygen",
      "total-radiation-dose",
      "extreme-cold",
      "vacuum-and-outgassing"
    ],
    "applications": [
      "cryogenic-fuel",
      "propulsion-and-tanks",
      "electronics-and-chips"
    ]
  },
  "properties": [
    {
      "benchmark": "atomic_oxygen_erosion_yield",
      "label": "Atomic oxygen erosion yield (MISSE 2, flight)",
      "value": 8.31e-25,
      "bound": "exact",
      "unit": "cm3/atom",
      "scope": "material",
      "conditions": {
        "flight": "MISSE 2 PEACE, ISS, 3.95 years",
        "fluence": "8.43e21 atoms/cm2",
        "sample": "PEACE polymer flight sample"
      },
      "method": "Measured erosion yield printed in the MISSE 2 PEACE polymer table; the value is copied as printed in the paper",
      "status": "flight",
      "source": "banks2008",
      "where": "Table I, row Chlorotrifluoroethylene CTFE (Kel-f); MISSE 2 column; Table VII repeats 8.31e-25",
      "source_detail": {
        "title": "NASA/TM-2008-215490: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit",
        "id": "NASA/TM-2008-215490 (Banks, Backus, de Groh, December 2008)",
        "url": "https://ntrs.nasa.gov/citations/20090011780",
        "year": 2008,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density (MISSE 2 sample, ref 12)",
      "value": 2.1327,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "polymer film sample used for the MISSE 2 study",
        "reference": "ref. 12 in the paper"
      },
      "method": "Density printed in the MISSE 2 PEACE polymer density table, copied as printed",
      "status": "ground",
      "source": "banks2008",
      "where": "Table II, row Chlorotrifluoroethylene CTFE (Kel-f)",
      "source_detail": {
        "title": "NASA/TM-2008-215490: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit",
        "id": "NASA/TM-2008-215490 (Banks, Backus, de Groh, December 2008)",
        "url": "https://ntrs.nasa.gov/citations/20090011780",
        "year": 2008,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "density",
      "label": "Specific gravity (Neoflon PCTFE M-400H resin)",
      "value": 2.11,
      "value_high": 2.16,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "form": "granular resin, compression-molding grade M-400H",
        "standard": "ASTM D-1430"
      },
      "method": "Typical property printed in the Daikin Technical Data Sheet, given as a range; the datasheet says typical properties are not for specification use",
      "status": "ground",
      "source": "daikin-m400h",
      "where": "Typical properties table, row Specific Gravity",
      "source_detail": {
        "title": "Technical Data Sheet NEOFLON PCTFE M-400H (Daikin Chemical Europe)",
        "id": "TDS NEOFLON PCTFE M-400H, dated 2025/02/20",
        "url": "https://www.daikinchem.de/wp-content/uploads/2025/03/Technical-Data-Sheet-Neoflon-PCTFE-M-400H.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet"
      }
    },
    {
      "benchmark": "density",
      "label": "Specific gravity (Neoflon PCTFE M-300H resin)",
      "value": 2.11,
      "value_high": 2.16,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "form": "granular resin, compression-molding grade M-300H",
        "standard": "ASTM D-1430"
      },
      "method": "Typical property printed in the Daikin Technical Data Sheet, given as a range; not for specification use",
      "status": "ground",
      "source": "daikin-m300h",
      "where": "Typical properties table, row Specific Gravity",
      "source_detail": {
        "title": "Technical Data Sheet NEOFLON PCTFE M-300H (Daikin Chemical Europe)",
        "id": "TDS NEOFLON PCTFE M-300H, dated 2025/02/20",
        "url": "https://www.daikinchem.de/wp-content/uploads/2025/03/Technical-Data-Sheet-Neoflon-PCTFE-M-300H.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point (DSC, M-400H resin)",
      "value": 210,
      "value_high": 212,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "method_detail": "DSC",
        "standard": "ASTM D-1430"
      },
      "method": "Typical property printed in the Daikin datasheet as a range",
      "status": "ground",
      "source": "daikin-m400h",
      "where": "Typical properties table, row Melting point (DSC)",
      "source_detail": {
        "title": "Technical Data Sheet NEOFLON PCTFE M-400H (Daikin Chemical Europe)",
        "id": "TDS NEOFLON PCTFE M-400H, dated 2025/02/20",
        "url": "https://www.daikinchem.de/wp-content/uploads/2025/03/Technical-Data-Sheet-Neoflon-PCTFE-M-400H.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Glass transition temperature (approximate)",
      "value": 45,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "stated as 'around 45 degC' in the Wikipedia article"
      },
      "method": "Single approximate value from a Wikipedia Properties paragraph; no primary measurement opened",
      "status": "ground",
      "source": "wiki-pctfe",
      "where": "Section 'Properties', first paragraph",
      "source_detail": {
        "title": "Polychlorotrifluoroethylene (Wikipedia)",
        "id": "Wikipedia article, accessed 2026-10-20",
        "url": "https://en.wikipedia.org/wiki/Polychlorotrifluoroethylene",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Heat resistance (upper use temperature, as stated)",
      "value": 175,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "text says 'the heat resistance is up to 175 degC'"
      },
      "method": "Single figure from a Wikipedia Properties paragraph; no datasheet service-temperature value was found for the resin",
      "status": "ground",
      "source": "wiki-pctfe",
      "where": "Section 'Properties', second paragraph",
      "source_detail": {
        "title": "Polychlorotrifluoroethylene (Wikipedia)",
        "id": "Wikipedia article, accessed 2026-10-20",
        "url": "https://en.wikipedia.org/wiki/Polychlorotrifluoroethylene",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength (M-400H resin, typical)",
      "value": 34,
      "value_high": 39,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D-1430",
        "temperature": "room temperature (datasheet)"
      },
      "method": "Typical property printed in the Daikin datasheet as a range",
      "status": "ground",
      "source": "daikin-m400h",
      "where": "Typical properties table, row Tensile strength",
      "source_detail": {
        "title": "Technical Data Sheet NEOFLON PCTFE M-400H (Daikin Chemical Europe)",
        "id": "TDS NEOFLON PCTFE M-400H, dated 2025/02/20",
        "url": "https://www.daikinchem.de/wp-content/uploads/2025/03/Technical-Data-Sheet-Neoflon-PCTFE-M-400H.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation (M-400H resin, typical)",
      "value": 100,
      "value_high": 250,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D-1430"
      },
      "method": "Typical property printed in the Daikin datasheet as a range",
      "status": "ground",
      "source": "daikin-m400h",
      "where": "Typical properties table, row Elongation",
      "source_detail": {
        "title": "Technical Data Sheet NEOFLON PCTFE M-400H (Daikin Chemical Europe)",
        "id": "TDS NEOFLON PCTFE M-400H, dated 2025/02/20",
        "url": "https://www.daikinchem.de/wp-content/uploads/2025/03/Technical-Data-Sheet-Neoflon-PCTFE-M-400H.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength (M-300H resin, typical)",
      "value": 32,
      "value_high": 37,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D-1430"
      },
      "method": "Typical property printed in the Daikin datasheet as a range",
      "status": "ground",
      "source": "daikin-m300h",
      "where": "Typical properties table, row Tensile strength",
      "source_detail": {
        "title": "Technical Data Sheet NEOFLON PCTFE M-300H (Daikin Chemical Europe)",
        "id": "TDS NEOFLON PCTFE M-300H, dated 2025/02/20",
        "url": "https://www.daikinchem.de/wp-content/uploads/2025/03/Technical-Data-Sheet-Neoflon-PCTFE-M-300H.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation (M-300H resin, typical)",
      "value": 50,
      "value_high": 200,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D-1430"
      },
      "method": "Typical property printed in the Daikin datasheet as a range",
      "status": "ground",
      "source": "daikin-m300h",
      "where": "Typical properties table, row Elongation",
      "source_detail": {
        "title": "Technical Data Sheet NEOFLON PCTFE M-300H (Daikin Chemical Europe)",
        "id": "TDS NEOFLON PCTFE M-300H, dated 2025/02/20",
        "url": "https://www.daikinchem.de/wp-content/uploads/2025/03/Technical-Data-Sheet-Neoflon-PCTFE-M-300H.pdf",
        "year": 2025,
        "kind": "datasheet",
        "license": "manufacturer datasheet"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength at 77 K (PCTFE film, before LOX immersion)",
      "value": 127.78,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temperature_k": 77,
        "film_thickness_mm": 0.05,
        "immersion": "0 days (untreated)",
        "direction": "not stated"
      },
      "method": "Mean printed in Table 2 (mean plus or minus 8.91 MPa, not entered); cryogenic tensile test in liquid nitrogen chamber",
      "status": "ground",
      "source": "mdpi-lox-films",
      "where": "Table 2, row Tensile strength (MPa), immersion 0 days, PCTFE column",
      "source_detail": {
        "title": "Cryogenic Mechanical Properties and Stability of Polymer Films for Liquid Oxygen Hoses (Polymers, MDPI, via PubMed Central)",
        "id": "PMC10457865",
        "url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457865/",
        "year": 2023,
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus at 77 K (PCTFE film, before LOX immersion)",
      "value": 5.65,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature_k": 77,
        "immersion": "0 days (untreated)"
      },
      "method": "Mean printed in Table 2 (mean plus or minus 0.16 GPa, not entered)",
      "status": "ground",
      "source": "mdpi-lox-films",
      "where": "Table 2, row Young's modulus (GPa), immersion 0 days, PCTFE column",
      "source_detail": {
        "title": "Cryogenic Mechanical Properties and Stability of Polymer Films for Liquid Oxygen Hoses (Polymers, MDPI, via PubMed Central)",
        "id": "PMC10457865",
        "url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457865/",
        "year": 2023,
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break at 77 K (PCTFE film, before LOX immersion)",
      "value": 4.01,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "temperature_k": 77,
        "immersion": "0 days (untreated)"
      },
      "method": "Mean printed in Table 2 (mean plus or minus 0.66 %, not entered)",
      "status": "ground",
      "source": "mdpi-lox-films",
      "where": "Table 2, row Elongation at break (%), immersion 0 days, PCTFE column",
      "source_detail": {
        "title": "Cryogenic Mechanical Properties and Stability of Polymer Films for Liquid Oxygen Hoses (Polymers, MDPI, via PubMed Central)",
        "id": "PMC10457865",
        "url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457865/",
        "year": 2023,
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "molar_mass",
      "label": "Molar mass of the repeat unit (C2ClF3)",
      "value": 116.4687,
      "bound": "exact",
      "unit": "g/mole",
      "scope": "material",
      "conditions": {
        "basis": "atomic mass of the repeat unit as tabulated"
      },
      "method": "Value printed in the MISSE 2 chemical structure table; the paper gives it per repeat unit",
      "status": "calculated",
      "source": "banks2008",
      "where": "Table IV, row Chlorotrifluoroethylene CTFE (Kel-f)",
      "source_detail": {
        "title": "NASA/TM-2008-215490: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit",
        "id": "NASA/TM-2008-215490 (Banks, Backus, de Groh, December 2008)",
        "url": "https://ntrs.nasa.gov/citations/20090011780",
        "year": 2008,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Atomic oxygen in low Earth orbit",
      "headline": "Atomic oxygen eroded PCTFE at 8.31e-25 cm3/atom on MISSE 2, far slower than Kapton H.",
      "effect": "The MISSE 2 table gives 8.31e-25 cm3/atom for CTFE (Kel-f), against 3.00e-24 for Kapton H and 1.42e-25 for PTFE.",
      "rating": "low",
      "conditions": {
        "flight": "MISSE 2, 3.95 years, fluence 8.43e21 atoms/cm2"
      },
      "source": "banks2008",
      "where": "Table I"
    },
    {
      "environment": "Liquid oxygen and cryogenic immersion",
      "headline": "PCTFE film stayed compatible with liquid oxygen for 60 days and kept its cryogenic strength.",
      "effect": "Tensile strength at 77 K was 127.78 MPa before immersion, 133.53 MPa after 7 days and 125.10 MPa after 60 days (Table 2).",
      "rating": "low",
      "conditions": {
        "temperature_k": 77,
        "immersion": "up to 60 days in liquid oxygen"
      },
      "source": "mdpi-lox-films",
      "where": "Table 2 and Conclusions"
    },
    {
      "environment": "Ionizing radiation",
      "headline": "Degrades under high-energy radiation like PTFE; no dose figure for PCTFE was read.",
      "effect": "The Wikipedia article says PCTFE undergoes degradation like PTFE when subjected to high-energy radiation.",
      "rating": "moderate",
      "conditions": {},
      "source": "wiki-pctfe",
      "where": "Section 'Properties', third paragraph"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "The monomer chlorotrifluoroethylene is an extremely flammable gas (H220) and contains gas under pressure that may explode if heated (H280).",
        "ghs": [
          "H220",
          "H280"
        ],
        "source": "pubchem-ctfe",
        "where": "GHS Classification, Hazard Statements (H220 at 89.2 percent, H280 at 89.9 percent of notifications)"
      },
      {
        "text": "The monomer is toxic if swallowed (H301, 29.5 percent of notifications) and toxic if inhaled (H331, 100 percent of notifications).",
        "ghs": [
          "H301",
          "H331"
        ],
        "source": "pubchem-ctfe",
        "where": "GHS Classification, Hazard Statements"
      },
      {
        "text": "Polymer hazard data were not found in a safety data sheet; the figures above refer to the monomer gas, not the solid polymer.",
        "ghs": [],
        "source": "wiki-ctfe",
        "where": "Hazards infobox (NFPA ratings and H-phrases for the monomer)"
      }
    ],
    "failure_risks": [
      {
        "mode": "Dimensional instability of PCTFE valve seats",
        "trigger": "Temperatures from 40 to 70 degC in oxygen regulator valve seats, with resin grade, crystallinity and process history affecting the result",
        "consequence": "A valve-seat study found dimensional instability of varying magnitude in this range; the authors discuss several proposed ignition mechanisms, including particle impact and localized heating by flow friction",
        "source": "ntrs-valve-seat",
        "where": "Abstract"
      },
      {
        "mode": "Radiation damage",
        "trigger": "High-energy radiation",
        "consequence": "Degrades like PTFE; no number was read for PCTFE",
        "source": "wiki-pctfe",
        "where": "Section 'Properties', third paragraph"
      }
    ],
    "side_effects": [
      {
        "text": "Under atomic oxygen in low Earth orbit the surface erodes slowly, but MISSE 2 gave a measurable erosion yield of 8.31e-25 cm3/atom.",
        "source": "banks2008",
        "where": "Table I"
      }
    ],
    "handling": [
      {
        "text": "Treat the monomer as a flammable, toxic gas under pressure and keep it away from heat; PubChem lists H220, H280, H301 and H331 for the monomer.",
        "source": "pubchem-ctfe",
        "where": "GHS Classification, Hazard Statements"
      }
    ],
    "mitigations": [
      {
        "text": "Use the polymer in liquid-oxygen and cryogenic service only where a liquid-oxygen compatibility test has been run; the film study found PCTFE compatible with liquid oxygen for 60 days.",
        "source": "mdpi-lox-films",
        "where": "Abstract and Conclusions (fluoropolymers compatible with LOX for 60 days)"
      }
    ]
  },
  "uses": [
    {
      "application": "cryogenic-fuel",
      "device": "Inner layer of a liquid-oxygen composite hose",
      "example": "The study tested PCTFE film as an inner layer for liquid-oxygen composite hoses and recommended it as the preferred material of four fluoropolymers",
      "source": "mdpi-lox-films",
      "where": "Conclusions, item (4)"
    },
    {
      "application": "propulsion-and-tanks",
      "device": "PCTFE valve seats in oxygen regulators",
      "example": "Actual valve seats of unspecified grade, made from Kel-F 81 or Neoflon CTFE M400H, were tested for dimensional stability; the seats are used in an oxygen regulator application",
      "source": "ntrs-valve-seat",
      "where": "Abstract"
    },
    {
      "application": "electronics-and-chips",
      "device": "Insulation of wires and cables and protective film for electronics",
      "example": "Used to protect sensitive electronic components because of its electrical resistance and water repulsion, and for flexible printed circuits",
      "source": "wiki-pctfe",
      "where": "Section 'Applications', paragraph on electronic components"
    }
  ],
  "supply": [
    {
      "subject": "Fluorine feedstock (fluorspar, calcium fluoride)",
      "producers": [
        {
          "country": "China",
          "share_percent": 60,
          "year": 2025
        },
        {
          "country": "Mexico",
          "share_percent": 15,
          "year": 2025
        },
        {
          "country": "Mongolia",
          "share_percent": 15,
          "year": 2025
        },
        {
          "country": "South Africa",
          "share_percent": 4.1,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: synthetic fluorspar may be produced from neutralization of waste in uranium enrichment, petroleum alkylation and stainless-steel pickling.",
      "substitutes": [],
      "source": "usgs-mcs2026-fluorspar",
      "where": "World Mine Production 2025 table (thousand tons: China 6,000, Mexico 1,500, Mongolia 1,500, South Africa 410, world total 10,000); shares computed from these figures"
    },
    {
      "subject": "PCTFE resin producers",
      "producers": [],
      "critical_lists": [],
      "substitutes": [],
      "source": "wiki-pctfe",
      "where": "Section 'Trade names': PCTFE is made as Neoflon PCTFE by Daikin, Voltalef by Arkema and Aclon by Honeywell, and Kel-F was discontinued by 3M by 1996. No country shares were read."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Mineral Commodity Summaries 2026: Fluorspar (USGS)",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf",
      "year": 2026
    },
    {
      "title": "NASA/TM-2008-215490: Atomic Oxygen Erosion Yield Predictive Tool",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/20090011780",
      "year": 2008
    },
    {
      "title": "Neoflon PCTFE M-400H Technical Data Sheet (Daikin)",
      "type": "datasheet",
      "url": "https://www.daikinchem.de/wp-content/uploads/2025/03/Technical-Data-Sheet-Neoflon-PCTFE-M-400H.pdf",
      "year": 2025
    },
    {
      "title": "Neoflon PCTFE M-300H Technical Data Sheet (Daikin)",
      "type": "datasheet",
      "url": "https://www.daikinchem.de/wp-content/uploads/2025/03/Technical-Data-Sheet-Neoflon-PCTFE-M-300H.pdf",
      "year": 2025
    }
  ],
  "gaps": [
    "No datasheet or primary paper gave a service temperature for the Kel-F or Neoflon resin; the 175 degC figure comes from Wikipedia only.",
    "The Daikin datasheets are typical values only and say so; no certified grade data was read.",
    "No ultraviolet or vacuum-ultraviolet exposure result for PCTFE was opened.",
    "No radiation dose-versus-property curve for PCTFE was opened; the Wikipedia article says only that it degrades like PTFE under high-energy radiation.",
    "No water vapour transmission figure was read; the Wikipedia article calls PCTFE the lowest water vapour transmission plastic without a number.",
    "The atomic-oxygen erosion yield and molar mass use names that are not in property-canon.yaml (atomic_oxygen_erosion_yield, molar_mass).",
    "Atomic weights for the recipe parts were not read in this run, so atomic_weight is left out.",
    "The cryogenic film results come from one 0.05 mm commercial film from Honeywell; the study does not state film direction.",
    "No PubChem record for the polymer was opened; the hazard data are for the monomer, chlorotrifluoroethylene (PubChem CID 6594).",
    "Supply: no country share table for chlorine or CTFE monomer makers was found; the fluorine feedstock shares are from USGS fluorspar 2025.",
    "Cited USGS fluorspar critical-mineral status was not found in the fetched report."
  ],
  "story": {
    "why": "PCTFE is a fluoropolymer that is closer to PTFE than to most plastics. Replacing one fluorine per repeat unit with chlorine loosens the chain packing, so PCTFE is tougher and easier to process than PTFE but melts lower (about 210 degC). NASA flew it on MISSE 2 and found good resistance to atomic oxygen.\n",
    "uses": [
      {
        "where": "Cryogenic liquid-oxygen hoses",
        "line": "A 2023 study tested PCTFE film at 77 K and found it compatible with liquid oxygen for 60 days, so it is a candidate inner layer for cryogenic hoses."
      },
      {
        "where": "Oxygen regulator valve seats",
        "line": "NASA tested PCTFE valve seats used in oxygen regulators for dimensional stability and reported instability between 40 and 70 degC."
      }
    ],
    "can_do": [
      {
        "label": "Atomic oxygen",
        "line": "On MISSE 2 the PCTFE sample eroded at 8.31e-25 cm3/atom after 3.95 years.",
        "scope": "material",
        "value": "8.31e-25 cm3/atom"
      },
      {
        "label": "Cryogenic strength",
        "line": "Before liquid-oxygen immersion the film had a tensile strength of 127.78 MPa at 77 K, the highest of the fluoropolymer films tested.",
        "scope": "material",
        "value": "127.78 MPa at 77 K"
      }
    ],
    "compare": "In low Earth orbit PCTFE eroded at 8.31e-25 cm3/atom on MISSE 2, against 1.42e-25 for PTFE and 3.00e-24 for Kapton H in the same table. Its density of 2.1327 g/cm3 is close to the 2.11 to 2.16 range of the Daikin PCTFE resins. At 77 K PCTFE has a tensile strength of 127.78 MPa and a 4.01 % elongation at break. Room-temperature typical tensile strength of the Daikin M-400H PCTFE resin is 34 to 39 MPa.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Max service temp",
        "benchmark": "max_service_temp",
        "scope": "material"
      },
      {
        "label": "Glass transition temperature",
        "benchmark": "glass_transition_temperature",
        "scope": "material"
      }
    ],
    "handling": [
      "Keep the resin dry and clean; it is supplied as granular powder or sheet.",
      "Heating above the melting point releases fumes; ventilate and do not overheat.",
      "Do not handle the monomer gas without training and gas-handling equipment."
    ],
    "good_for": [
      "Cryogenic liquid-oxygen seals and hoses, where the film kept its strength at 77 K.",
      "Moisture barriers and chemically inert linings.",
      "Atomic oxygen exposure in low Earth orbit, with erosion far below Kapton H."
    ],
    "watch_out": [
      "Radiation: it degrades under high-energy radiation like PTFE.",
      "Dimensional stability: valve-seat tests showed movement from 40 to 70 degC.",
      "Monomer hazard: the gas is extremely flammable and toxic."
    ],
    "verdict": "PCTFE is a chemically inert, low-erosion fluoropolymer with good strength at liquid-oxygen temperature. It is the stronger and stiffer choice over PTFE for cryogenic seals and liquid-oxygen hoses, but its service limit and radiation sensitivity mean it suits shielded or cold service rather than long exposed surfaces.\n",
    "recipe": {
      "line": "PCTFE is an addition homopolymer made by free-radical polymerization of one monomer, chlorotrifluoroethylene (CTFE, C2ClF3). It can be made by solution, bulk, suspension or emulsion polymerization (Wikipedia).",
      "parts": [
        {
          "name": "Carbon",
          "symbol": "C",
          "role": "The two backbone carbons of each repeat unit."
        },
        {
          "name": "Chlorine",
          "symbol": "Cl",
          "role": "One chlorine per repeat unit, the substitution that separates PCTFE from PTFE."
        },
        {
          "name": "Fluorine",
          "symbol": "F",
          "role": "Three fluorine atoms per repeat unit, which give chemical inertness."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The polymer is a solid, but the monomer is an extremely flammable and toxic gas, and overheating the polymer can release fumes.",
        "points": [
          {
            "label": "The monomer",
            "line": "PubChem lists chlorotrifluoroethylene as extremely flammable (H220), may explode if heated (H280), and toxic if swallowed or inhaled (H301, H331)."
          }
        ],
        "level": 2,
        "verdict": "Safe as a solid resin; the monomer gas is the hazard"
      }
    ]
  },
  "updated": "2026-10-20",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 0,
    "unreachable": 0,
    "caveats": 0,
    "note": "Written by an AI assistant on 2026-10-20. Values read in this run from the NASA MISSE 2 PDF (Banks et al.), the Daikin M-400H and M-300H datasheets, the MDPI cryogenic film paper (PMC), the NASA NTRS abstract, the USGS fluorspar summary, PubChem and Wikipedia."
  },
  "sources": {
    "banks2008": {
      "title": "NASA/TM-2008-215490: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit",
      "id": "NASA/TM-2008-215490 (Banks, Backus, de Groh, December 2008)",
      "url": "https://ntrs.nasa.gov/citations/20090011780",
      "year": 2008,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "usgs-mcs2026-fluorspar": {
      "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)"
    },
    "wiki-pctfe": {
      "title": "Polychlorotrifluoroethylene (Wikipedia)",
      "id": "Wikipedia article, accessed 2026-10-20",
      "url": "https://en.wikipedia.org/wiki/Polychlorotrifluoroethylene",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0"
    },
    "wiki-ctfe": {
      "title": "Chlorotrifluoroethylene (Wikipedia)",
      "id": "Wikipedia article, accessed 2026-10-20",
      "url": "https://en.wikipedia.org/wiki/Chlorotrifluoroethylene",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0"
    },
    "pubchem-ctfe": {
      "title": "Chlorotrifluoroethylene, PubChem CID 6594 (GHS classification)",
      "id": "PubChem CID 6594",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/6594",
      "year": 2026,
      "kind": "database",
      "license": "public domain (NIH)"
    },
    "daikin-m400h": {
      "title": "Technical Data Sheet NEOFLON PCTFE M-400H (Daikin Chemical Europe)",
      "id": "TDS NEOFLON PCTFE M-400H, dated 2025/02/20",
      "url": "https://www.daikinchem.de/wp-content/uploads/2025/03/Technical-Data-Sheet-Neoflon-PCTFE-M-400H.pdf",
      "year": 2025,
      "kind": "datasheet",
      "license": "manufacturer datasheet"
    },
    "daikin-m300h": {
      "title": "Technical Data Sheet NEOFLON PCTFE M-300H (Daikin Chemical Europe)",
      "id": "TDS NEOFLON PCTFE M-300H, dated 2025/02/20",
      "url": "https://www.daikinchem.de/wp-content/uploads/2025/03/Technical-Data-Sheet-Neoflon-PCTFE-M-300H.pdf",
      "year": 2025,
      "kind": "datasheet",
      "license": "manufacturer datasheet"
    },
    "ntrs-valve-seat": {
      "title": "Comparison of The Dimensional Stability of Kel-F 81 and Neoflon CTFE M400H Polychlorotrifluoroethylenes Used in Valve Seat Application (NASA NTRS)",
      "id": "NASA NTRS Document ID 20000102416 (Waller, Beeson, Newton, Fries; 9th Int. Symposium on Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres, 2000)",
      "url": "https://ntrs.nasa.gov/citations/20000102416",
      "year": 2000,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "mdpi-lox-films": {
      "title": "Cryogenic Mechanical Properties and Stability of Polymer Films for Liquid Oxygen Hoses (Polymers, MDPI, via PubMed Central)",
      "id": "PMC10457865",
      "url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10457865/",
      "year": 2023,
      "kind": "paper",
      "license": "CC BY 4.0"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/ctfe-kel-f/"
}