Polychlorotrifluoroethylene PCTFE (CTFE, Kel-F)

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.
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
  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
    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
  - benchmark: density
    label: Density (MISSE 2 sample, ref 12)
    value: 2.1327
    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)
  - benchmark: density
    label: Specific gravity (Neoflon PCTFE M-400H resin)
    value: 2.11
    value_high: 2.16
    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
  - benchmark: density
    label: Specific gravity (Neoflon PCTFE M-300H resin)
    value: 2.11
    value_high: 2.16
    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
  - benchmark: melting_point
    label: Melting point (DSC, M-400H resin)
    value: 210
    value_high: 212
    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)
  - benchmark: glass_transition_temperature
    label: Glass transition temperature (approximate)
    value: 45
    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
  - benchmark: max_service_temp
    label: Heat resistance (upper use temperature, as stated)
    value: 175
    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
  - benchmark: ultimate_tensile_strength
    label: Tensile strength (M-400H resin, typical)
    value: 34
    value_high: 39
    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
  - benchmark: elongation
    label: Elongation (M-400H resin, typical)
    value: 100
    value_high: 250
    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
  - benchmark: ultimate_tensile_strength
    label: Tensile strength (M-300H resin, typical)
    value: 32
    value_high: 37
    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
  - benchmark: elongation
    label: Elongation (M-300H resin, typical)
    value: 50
    value_high: 200
    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
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at 77 K (PCTFE film, before LOX immersion)
    value: 127.78
    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
  - benchmark: elastic_modulus
    label: Young's modulus at 77 K (PCTFE film, before LOX immersion)
    value: 5.65
    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
  - benchmark: elongation
    label: Elongation at break at 77 K (PCTFE film, before LOX immersion)
    value: 4.01
    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
  - benchmark: molar_mass
    label: Molar mass of the repeat unit (C2ClF3)
    value: 116.4687
    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)
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.
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
story:
  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
      level: 2
      verdict: Safe as a solid resin; the monomer gas is the hazard
      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).
  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.
  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
      value: 8.31e-25 cm3/atom
      line: On MISSE 2 the PCTFE sample eroded at 8.31e-25 cm3/atom after 3.95 years.
    - label: Cryogenic strength
      value: 127.78 MPa at 77 K
      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.
  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.
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
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
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
    recycling: 'USGS: synthetic fluorspar may be produced from neutralization of waste in uranium enrichment, petroleum alkylation and stainless-steel pickling.'
    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: []
    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.'
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
checked_values: 14
license: CC-BY-4.0
updated: 2026-10-20T00:00:00.000Z
review:
  status: draft
  method: assistant
  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.