spore: profile
id: ectfe-halar
spore_version: 0.2
family: fluoropolymers
name: Ethylene-chlorotrifluoroethylene
abbreviation: ECTFE (Halar)
role: tough, chemically resistant semi-crystalline fluoropolymer for linings, pipes and cable jackets
category: polymers
type: fluoropolymers
summary: |
  ECTFE (Halar, from Solvay) is an alternating copolymer of ethylene and chlorotrifluoroethylene. It is tougher than PTFE, has a continuous service range of -76 °C to +150 °C and resists most acids, alkalis and solvents. On the MISSE 2 flight it eroded under atomic oxygen at 1.79e-24 cm3/atom, about the same as Kapton H and far worse than PTFE. Its weak points are atomic oxygen compared with PTFE, and overheating above about 350 °C, which releases hydrogen fluoride.
best_for: Corrosion-resistant linings, pipes and tanks, and wire or cable jacketing that must survive acids and solvents and still be tough
weakest_at: Atomic oxygen in low Earth orbit (far more than PTFE on the MISSE 2 flight) and overheating, which gives toxic and corrosive fumes including hydrogen fluoride
identity:
  formula: (C2H4)n(C2ClF3)n, alternating copolymer; repeat unit C4H4ClF3
  cas: 25101-45-5
  source: wiki-ectfe
  where: Infobox (CAS 25101-45-5, alternating copolymer of ethylene and chlorotrifluoroethylene); PubChem record 25101-45-5 gives the formula (C2H4.C2ClF3)x; repeat unit C4H4ClF3 from the NASA MISSE 2 table
tags:
  environments:
    - low-earth-orbit
  stresses:
    - atomic-oxygen
    - uv
  applications:
    - electronics-and-chips
    - cryogenic-fuel
properties:
  - benchmark: atomic_oxygen_erosion_yield
    label: Atomic oxygen erosion yield (MISSE 2 flight)
    value: 1.79e-24
    unit: cm3/atom
    scope: material
    conditions:
      environment: low Earth orbit, ISS, MISSE 2 PEACE Polymers tray
      fluence: 8.43e21 atoms/cm2
      duration: 3.95 years
    method: Flight measurement reported in a NASA technical memorandum predictive-tool table
    status: flight
    source: banks2008
    where: Table I, row Ethylene-chlorotrifluoroethylene, ECTFE (Halar)
  - benchmark: density
    label: Specific gravity (D792)
    value: 1.68
    unit: g/cm3
    scope: material
    conditions:
      test_standard: ASTM D792
      form: typical value, Halar ECTFE
    method: Typical value printed in a materials data sheet
    status: ground
    source: wk-halar
    where: Typical properties table, PHYSICAL, Density (g/cm3) row
  - benchmark: density
    label: Density range (Halar 901S SDS)
    value: 1.65
    value_high: 1.71
    unit: g/cm3
    scope: material
    conditions:
      form: Halar 901S resin
    method: Range printed in a manufacturer safety data sheet, Section 9
    status: ground
    source: gfps-sds
    where: Section 9, Density row (Revision 08.09.2016)
  - benchmark: melting_point
    label: Melting point
    value: 238
    unit: °C
    scope: material
    conditions:
      printed: 460 °F
      test_standard: ASTM D3418
    method: Typical value printed in a materials data sheet
    status: ground
    note: The Halar 901S safety data sheet gives a melting range of 230 to 242 °C.
    source: wk-halar
    where: Thermal table, Melting Temp (°F / °C) row
  - benchmark: heat_deflection_temperature
    label: Heat deflection temperature at 264 psi
    value: 115
    unit: °C
    scope: material
    conditions:
      pressure: 264 psi
      test_standard: ASTM D648
      printed: 240 °F
    method: Typical value printed in a materials data sheet
    status: ground
    source: wk-halar
    where: Thermal table, Heat Deflection Temp row
  - benchmark: max_service_temp
    label: Maximum operating temperature (data sheet)
    value: 149
    unit: °C
    scope: material
    conditions:
      printed: 300 °F
      basis: typical performance in many applications
    method: Typical value printed in a materials data sheet
    status: ground
    source: wk-halar
    where: Thermal table, Max Operating Temp row
  - benchmark: max_service_temp
    label: Upper service temperature (rod stock)
    value: 150
    unit: °C
    scope: material
    conditions:
      form: Halar 901 rod, machined stock
      printed: 302 °F
    method: Printed value on a supplier product sheet
    status: ground
    source: pexco-ectfe
    where: Specifications box, Temperature line
  - benchmark: min_service_temp
    label: Continuous usage lower limit
    value: -76
    unit: °C
    scope: material
    conditions:
      basis: continuous usage temperature range (-105 °F to +300 °F as printed)
    method: Range stated in a reference encyclopedia article, which cites the Polymer Handbook and manufacturer data
    status: ground
    source: wiki-ectfe
    where: Physical and chemical properties section, first paragraph
  - benchmark: ultimate_tensile_strength
    label: Tensile strength (data sheet)
    value: 7000
    unit: psi
    scope: material
    conditions:
      test_standard: ASTM D638
      form: typical value, Halar ECTFE
    method: Typical value printed in a materials data sheet
    status: ground
    source: wk-halar
    where: Mechanical table, Tensile Strength row
  - benchmark: ultimate_tensile_strength
    label: Tensile strength (rod stock)
    value: 8000
    unit: psi
    scope: material
    conditions:
      test_standard: ASTM D638
      form: Halar 901 rod
    method: Printed value on a supplier product sheet
    status: ground
    source: pexco-ectfe
    where: Tensile Strength row
  - benchmark: elongation
    label: Elongation at break (data sheet)
    value: 200
    unit: '%'
    scope: material
    conditions:
      test_standard: ASTM D638
      form: typical value, Halar ECTFE
    method: Typical value printed in a materials data sheet
    status: ground
    source: wk-halar
    where: Mechanical table, Tensile Elongation at Break row
  - benchmark: elongation
    label: Elongation at break (rod stock)
    value: 250
    unit: '%'
    scope: material
    conditions:
      test_standard: ASTM D638
      form: Halar 901 rod
    method: Printed value on a supplier product sheet
    status: ground
    source: pexco-ectfe
    where: Elongation at Break row
  - benchmark: elastic_modulus
    label: Tensile modulus
    value: 240000
    unit: psi
    scope: material
    conditions:
      test_standard: ASTM D638
      form: typical value, Halar ECTFE
    method: Typical value printed in a materials data sheet
    status: ground
    source: wk-halar
    where: Mechanical table, Tensile Modulus row
  - benchmark: dielectric_constant
    label: Dielectric constant at 1 MHz
    value: 2.5
    unit: none
    scope: material
    conditions:
      test_standard: ASTM D150
      frequency: 1 MHz
      temperature: 23 °C
    method: Typical value printed in a materials data sheet
    status: ground
    source: wk-halar
    where: Electrical table, Dielectric Constant at 1 MHz row
  - benchmark: dielectric_strength
    label: Dielectric strength (short time)
    value: 500
    unit: V/mil
    scope: material
    conditions:
      test_standard: ASTM D149
      thickness: 1/8 inch
    method: Typical value printed in a materials data sheet
    status: ground
    source: wk-halar
    where: Electrical table, Dielectric Strength row
  - benchmark: electrical_resistivity
    label: Volume resistivity
    value: 1000000000000000
    unit: ohm-cm
    scope: material
    conditions:
      humidity: 50% RH
      printed: 1015 (exponent printed as superscript)
    method: Typical value printed in a materials data sheet
    status: ground
    source: wk-halar
    where: Electrical table, Volume Resistivity row
  - benchmark: moisture_absorption
    label: Water absorption, 24 hours
    value: 0.1
    unit: '%'
    scope: material
    conditions:
      test_standard: ASTM D570
      time: 24 hours
      printed: < 0.1
    method: Typical value printed in a materials data sheet, shown as less than 0.1
    status: ground
    source: wk-halar
    where: Physical table, Water Absorption row
  - benchmark: thermal_conductivity
    label: Thermal conductivity
    value: 0.000375
    unit: cal/cm-sec-°C
    scope: material
    conditions:
      test_standard: ASTM C177
      printed: 3.75 x 10-4 cal/cm-sec-°C (also 1.09 BTU-in/ft2-hr-°F)
    method: Typical value printed in a materials data sheet; printed value is 3.75 multiplied by 10-4, copied as 3.75e-4
    status: ground
    source: wk-halar
    where: Thermal table, Thermal Conductivity row
  - benchmark: cte
    label: Coefficient of linear thermal expansion
    value: 0.000056
    unit: in/in/°F
    scope: material
    conditions:
      test_standard: ASTM D696
      printed: 5.6 x 10-5 in/in/°F
    method: Typical value printed in a materials data sheet; printed value is 5.6 multiplied by 10-5, copied as 5.6e-5
    status: ground
    source: wk-halar
    where: Thermal table, Coefficient of Linear Thermal Expansion row
  - benchmark: hardness
    label: Hardness, Shore D
    value: 75
    unit: Shore D
    scope: material
    conditions:
      test_standard: ASTM D2240
      form: Halar 901 rod
    method: Printed value on a supplier product sheet
    status: ground
    source: pexco-ectfe
    where: Hardness row
  - benchmark: elastic_modulus
    label: Young's modulus (approximate)
    value: 1700
    unit: MPa
    scope: material
    conditions:
      basis: value printed in a reference encyclopedia article
    method: Value printed in a reference encyclopedia article
    status: ground
    source: wiki-ectfe
    where: Physical and chemical properties section, sentence on impact strength and Young's modulus
corrosion:
  - environment: Atomic oxygen in low Earth orbit
    headline: Atomic oxygen eroded ECTFE about as fast as Kapton H on the ISS, and far faster than PTFE (1.42e-25 cm3/atom).
    effect: On the MISSE 2 flight ECTFE had an erosion yield of 1.79e-24 cm3/atom, against 3.00e-24 for Kapton H and 1.42e-25 for PTFE in the same table. FEP measured 2.00e-25 and PFA 1.73e-25.
    rating: moderate
    conditions:
      flight: MISSE 2, 3.95 years, fluence 8.43e21 atoms/cm2
    source: banks2008
    where: Table I
  - environment: Acids, alkalis and organic solvents
    headline: ECTFE resists most acids, alkalis and solvents, but not hot amines or ketones.
    effect: The Halar data sheet says the material is resistant to most chemicals, including acids, alkalines and organic solvents, except hot amines and ketones. Wikipedia says its chemical resistance is similar to PTFE, though somewhat lower in some cases.
    rating: unknown
    conditions:
      basis: manufacturer and distributor data sheet, encyclopedia article
    source: wk-halar
    where: General properties paragraph
  - environment: Ultraviolet light
    headline: ECTFE has good UV resistance, particularly to UV-A and UV-B.
    effect: No UV exposure number was read. The encyclopedia article states the material has good UV resistance, and films can be transparent.
    rating: unknown
    conditions:
      basis: qualitative statement only
    source: wiki-ectfe
    where: Physical and chemical properties section
  - environment: Overheating above about 350 °C (decomposition)
    headline: Above about 350 °C ECTFE breaks down and gives off hydrogen fluoride and other toxic gases.
    effect: The Simona safety data sheet gives thermal decomposition from 350 °C and says that above this temperature the material breaks down into toxic fluorine-containing substances, and that burning gives hydrofluoric acid. The Halar 901S sheet lists hydrogen fluoride and hydrogen chloride as combustion products.
    rating: severe
    conditions:
      trigger: overheating or burning
      worst_case: poor ventilation
    source: simona-sds
    where: Section 10, Thermal decomposition and hazardous decomposition products
risks:
  hazards:
    - text: 'Halar 901S safety data sheet: the product is not labelled as hazardous under the regulation applied, but thermal decomposition can lead to release of toxic and corrosive gases. The thermal decomposition vapours of fluorinated polymers may cause polymer fume fever with flu-like symptoms.'
      ghs: []
      source: gfps-sds
      where: Sections 2.2 and 2.3; Section 11, Effects
    - text: 'Halar 901S sheet threshold limits for hydrogen fluoride from thermal decomposition: ACGIH ceiling 2 ppm (USA); the sheet also lists TWA 0.5 ppm (ACGIH).'
      ghs: []
      source: gfps-sds
      where: Section 8, threshold limit values of by-products from thermal decomposition
    - text: PubChem record for the copolymer (CAS 25101-45-5) gives no GHS hazard classification, and the material is listed as active under the EPA TSCA inventory.
      ghs: []
      source: pubchem-ectfe
      where: Sections 8.1 and 8.2
  failure_risks:
    - mode: Permeation by small molecules in lining service
      trigger: Exposure of a lining to water vapour, oxygen, chlorine, hydrogen sulfide, HCl or HF
      consequence: Small molecules permeate the matrix and can reach the underlying steel or fibre-reinforced plastic, which limits the lining lifetime.
      severity: moderate
      source: wiki-ectfe
      where: Physical and chemical properties section
    - mode: Hydrogen fluoride release on overheating
      trigger: Heating above about 350 °C
      consequence: The polymer breaks down into toxic and corrosive gases, including hydrogen fluoride, which can cause severe lung injury.
      severity: high
      source: simona-sds
      where: Section 10
  side_effects:
    - text: Thermal decomposition products can cause polymer fume fever in people, with flu-like symptoms.
      affects: People handling hot material
      source: gfps-sds
      where: Section 11, Effects
  handling:
    - text: To avoid thermal decomposition, do not overheat the material and keep it away from heat and ignition sources. Take measures to prevent a build-up of static electricity.
      source: gfps-sds
      where: Section 7, handling advice
    - text: Keep the product away from tobacco and do not contaminate tobacco products with it.
      source: gfps-sds
      where: Section 7, handling advice
  mitigations:
    - text: Provide local ventilation suited to the decomposition risk. In case of decomposition use breathing apparatus with a face mask.
      source: gfps-sds
      where: Section 8 and Section 8.2 (exposure controls and firefighting)
uses:
  - application: electronics-and-chips
    device: Primary and secondary jacketing of specialty data and heating cables, and wet benches for semiconductor processing
    example: The encyclopedia article says ECTFE is used for cable jacketing where fire resistance and electrical properties matter, and that it has been widely used for wet tool and tubing systems for lithographic chemicals.
    source: wiki-ectfe
    where: Applications section
  - application: cryogenic-fuel
    device: Gaskets for storing liquid oxygen and other propellants in aerospace systems
    example: The encyclopedia article says ECTFE is used for manufacturing gaskets to store liquid oxygen and other propellants for aerospace applications, and that it keeps high impact strength in cryogenic applications.
    source: wiki-ectfe
    where: Applications and Physical and chemical properties sections
  - application: structures
    device: Pipes, fittings, tanks and linings for the chemical industry
    example: Halar sheet and pipe are used for chemical handling, process tanks, pump and valve components and wet-process tool parts, and the material is also used in sheet lining of metal and fibre-reinforced plastic.
    source: wk-halar
    where: General properties and Typical applications
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, though impurities constrain its use. Primary aluminum producers recycle HF and fluorides from smelting.'
    substitutes:
      - 'USGS: fluosilicic acid has been used as an alternative to fluorspar in making AlF3 and HF.'
    source: usgs-mcs2026-fluorspar
    where: 'World Mine Production table, 2025e. Shares are calculated by Space Mushroom as 2025e tonnes divided by the printed world total of 10,000 thousand t (China 6,000; Mexico 1,500; Mongolia 1,500; South Africa 410). Import sources 2021-24: Mexico 64 percent, Vietnam 12 percent, China 10 percent, South Africa 9 percent. Fluorspar is the feedstock for hydrogen fluoride, which is used to make the fluorine in fluoropolymers.'
  - subject: ECTFE resin producer
    producers: []
    source: wk-halar
    where: The Halar trademark is registered to Solvay (Solvay Solexis); the Pexco sheet calls its resin 100 percent virgin Solvay Halar 901 ECTFE. No country shares for ECTFE resin makers were found, so none are entered.
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: Halar Materials Data Sheet (White Knight Fluid Handling, published 27 Feb 2025)
    type: datasheet
    url: https://wkfluidhandling.com/wp-content/media/materials/ectfe-halar.pdf
    year: 2025
  - title: Pexco ECTFE Rod product sheet (February 2026)
    type: datasheet
    url: https://www.pexco.com/wp-content/uploads/2026/02/Pexco-ECTFE-Rod_productsheet_Feb2026.pdf
    year: 2026
  - title: Halar 901S Safety Data Sheet (GFPS, revision 08.09.2016)
    type: sds
    url: https://www.gfps.com/content/dam/gfps/us/products/piping-systems/sygef-ectfe/Extrusion%20-%20Halar%20901S-SDS_GB-EN-2.04.pdf
    year: 2016
  - title: ECTFE Safety Data Sheet (Simona, distributed by Boedeker)
    type: sds
    url: https://www.boedeker.com/Portals/0/Safety%20Data%20Sheets%20SDS/Simona/ECTFE-SDS-Safety-Data-Sheet-Simona-Boedeker-2017.pdf
    year: 2017
  - title: 'Mineral Commodity Summaries 2026: Fluorspar (USGS)'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf
    year: 2026
  - title: PubChem record for ethylene-chlorotrifluoroethylene copolymer (CID not assigned, CAS 25101-45-5)
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/25101-45-5
    year: 2026
  - title: NIST Atomic Weights and Isotopic Compositions for All Elements
    type: database
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&all=all&ascii=html
    year: 2026
gaps:
  - No Solvay primary datasheet was opened. The values come from distributor and fabricator sheets that reproduce Solvay figures, and the file says so in each source.
  - No radiation dose data for ECTFE was found or read. The tags do not list total-radiation-dose.
  - No outgassing value for ECTFE was read from the NASA outgassing database or NASA RP-1124.
  - No ECTFE radiation, cryogenic tensile or vacuum-UV number from a primary paper was read; the cryogenic statement is qualitative only.
  - The polymerization process for ECTFE was not read in a fetched source, so the recipe gives composition only.
  - No GHS classification was found; PubChem has none and the Halar 901S sheet is not labelled hazardous.
  - No country shares for ECTFE resin producers were found.
  - The Wikipedia article gives the Young's modulus as approximate (about 1700 MPa) without a test standard, so the entry is marked as approximate.
  - Atomic weights for carbon and chlorine are printed by NIST as intervals, not single values; the file uses the printed interval lower bounds.
  - No quantitative chemical-resistance table (for example a percent change in mass or strength) was opened.
  - Hardness (Rockwell R93 on the Halar sheet) and flexural and compressive values were not entered as separate properties.
sources:
  banks2008:
    title: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit
    id: NASA/TM-2008-215490, NTRS 20090011780 (Banks, de Groh, Backus; December 2008)
    url: https://ntrs.nasa.gov/citations/20090011780
    year: 2008
    kind: report
    license: public domain (NASA)
  wk-halar:
    title: Polyethylene Chlorotrifluoroethylene (ECTFE or Halar) Materials Data Sheet, White Knight Fluid Handling (a Graco company)
    id: Published 27 Feb 2025, typical values
    url: https://wkfluidhandling.com/wp-content/media/materials/ectfe-halar.pdf
    year: 2025
    kind: datasheet
    license: supplier document, linked not reproduced
  pexco-ectfe:
    title: Pexco ECTFE Rod product sheet (Halar 901 resin)
    id: Pexco product sheet, February 2026
    url: https://www.pexco.com/wp-content/uploads/2026/02/Pexco-ECTFE-Rod_productsheet_Feb2026.pdf
    year: 2026
    kind: datasheet
    license: supplier document, linked not reproduced
  gfps-sds:
    title: Halar 901S Safety Data Sheet (GFPS)
    id: Revision 08.09.2016, version 2.04
    url: https://www.gfps.com/content/dam/gfps/us/products/piping-systems/sygef-ectfe/Extrusion%20-%20Halar%20901S-SDS_GB-EN-2.04.pdf
    year: 2016
    kind: datasheet
    license: manufacturer document, linked not reproduced
  simona-sds:
    title: ECTFE Safety Data Sheet (Simona, distributed by Boedeker)
    id: Simona ECTFE safety data sheet, 2017
    url: https://www.boedeker.com/Portals/0/Safety%20Data%20Sheets%20SDS/Simona/ECTFE-SDS-Safety-Data-Sheet-Simona-Boedeker-2017.pdf
    year: 2017
    kind: datasheet
    license: manufacturer document, linked not reproduced
  usgs-mcs2026-fluorspar:
    title: Mineral Commodity Summaries 2026, Fluorspar (U.S. Geological Survey)
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  pubchem-ectfe:
    title: Ethylene-chlorotrifluoroethylene copolymer (PubChem Compound, CAS 25101-45-5)
    id: PubChem record 25101-45-5, read in this run
    url: https://pubchem.ncbi.nlm.nih.gov/compound/25101-45-5
    year: 2026
    kind: database
    license: PubChem (NLM) terms
  nist-atomic-weights:
    title: Atomic Weights and Isotopic Compositions for All Elements (NIST)
    id: NIST composition tables, read in this run
    where: 'Printed standard atomic weights read in this run: C [12.0096, 12.0116]; H [1.00784, 1.00811]; Cl [35.446, 35.457]; F 18.998403163. Repeat-unit molar mass 144.5223 for C4H4ClF3 is from the NASA MISSE 2 table (banks2008).'
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&all=all&ascii=html
    year: 2026
    kind: database
    license: public domain (NIST)
  wiki-ectfe:
    title: ECTFE (Wikipedia)
    id: Wikipedia article, read in this run
    url: https://en.wikipedia.org/wiki/ECTFE
    year: 2026
    kind: web
    license: CC BY-SA 4.0
license: CC-BY-4.0
updated: '2026-10-20'
review:
  status: draft
  method: assistant
  checked_values: 21
  unreachable: 1
  caveats: 6
  note: Written by an AI assistant on 2026-10-20 from pages fetched in this run. The NASA memorandum table, the White Knight and Pexco sheets, the Halar 901S and Simona safety data sheets, the USGS fluorspar summary, the PubChem record, the NIST atomic weights and the Wikipedia article were read directly. The Solvay primary datasheet was not reachable through search. No values were taken from memory or search snippets.
story:
  recipe:
    line: ECTFE is made by polymerizing ethylene and chlorotrifluoroethylene (CTFE) into an alternating copolymer, a semi-crystalline fluoropolymer (Wikipedia). The repeat unit is C4H4ClF3 with a molar mass of 144.5223 (NASA MISSE 2 table). The polymerization process was not read in a fetched source.
    parts:
      - name: Carbon
        symbol: C
        role: 'Backbone carbons: two from ethylene and two from CTFE in each repeat unit.'
      - name: Hydrogen
        symbol: H
        role: Four hydrogens on the ethylene carbons, which give the copolymer its toughness compared with PTFE.
      - name: Chlorine
        symbol: Cl
        role: One chlorine on the CTFE unit, which fills free volume and keeps permeation low.
      - name: Fluorine
        symbol: F
        atoms: 3
        atomic_weight: 18.998403163
        role: Three fluorines on the CTFE unit, which give chemical resistance.
  risk_groups:
    - title: For people
      level: 2
      verdict: Not labelled hazardous as a solid; toxic fumes when…
      lead: The solid is not labelled hazardous, but overheating ECTFE releases hydrogen fluoride and other toxic gases.
      points:
        - label: The solid
          line: The Halar 901S safety data sheet says the product is not labelled as hazardous, but thermal decomposition can release toxic and corrosive gases.
        - label: Fume fever
          line: Thermal decomposition vapours of fluorinated polymers may cause polymer fume fever, a flu-like illness.
        - label: Above 350 °C
          line: The Simona safety data sheet gives thermal decomposition from 350 °C, with hydrofluoric acid as a product of burning.
    - title: If it fails
      lead: These results come from a flight measurement, data sheets and a safety sheet, not from a reported failure of a flown ECTFE part.
      points:
        - label: In orbit
          line: On the MISSE 2 flight ECTFE eroded at 1.79e-24 cm3/atom, about the same as Kapton H (3.00e-24) and far faster than PTFE (1.42e-25 cm3/atom) (1.42e-25).
        - label: Overheating
          line: Above about 350 °C the material breaks down into toxic fluorine-containing gases; the Halar sheet lists hydrogen fluoride as a combustion product.
        - label: Lining permeation
          line: Small molecules such as water, oxygen, chlorine and HF permeate the matrix and can limit the lifetime of a lining.
    - title: Handling and storage
      points:
        - label: Do not overheat
          line: Keep ECTFE away from heat and ignition sources, and do not overheat it.
        - label: Ventilate
          line: Provide local ventilation suited to the decomposition risk; in a fire use breathing apparatus with a face mask.
        - label: Static
          line: Take measures to prevent a build-up of static electricity when handling it.
  why: ECTFE (Halar) is an alternating copolymer of ethylene and chlorotrifluoroethylene. Mixing hydrogen-bearing ethylene units with fluorinated units gives a material that is tougher than PTFE, while keeping the chemical resistance of a fluoropolymer. A data sheet gives a density of 1.68 g/cm3, a melting point of 238 °C and a heat deflection temperature of 115 °C at 264 psi. Wikipedia gives a continuous range of -76 °C to +150 °C and a tensile strength of about 7000 psi from the data sheet. ECTFE is used where a tough, chemically resistant and fire-resistant plastic is needed, such as linings, pipes and cable jackets.
  uses:
    - where: Chemical lining and piping
      line: Halar sheet and pipe are used in chemical handling, process tanks, pump and valve parts and wet-process tools; sheet lining is also applied to metal and fibre-reinforced plastic.
    - where: Cable jacketing and semiconductor wet benches
      line: ECTFE is used for primary and secondary jacketing of specialty cables and for wet tool and tubing systems for lithographic chemicals.
    - where: Propellant gaskets
      line: ECTFE is used to make gaskets for storing liquid oxygen and other propellants in aerospace systems.
  can_do:
    - label: Atomic oxygen
      value: 1.79e-24 cm3/atom
      line: On the MISSE 2 flight ECTFE eroded at 1.79e-24 cm3/atom over 3.95 years, against 3.00e-24 for Kapton H in the same table.
    - label: Chemicals
      value: Resistant to most acids and solvents
      line: The Halar data sheet says the material resists most chemicals, including acids, alkalines and organic solvents, except hot amines and ketones.
    - label: Heat
      value: Melts at 238 °C
      line: A data sheet gives a melting point of 238 °C (460 °F) and a maximum operating temperature of 149 °C, and Wikipedia gives a continuous range up to +150 °C.
    - label: Electrical insulation
      value: 1e15 ohm-cm
      line: A data sheet gives a volume resistivity of 1e15 ohm-cm at 50 percent RH, a dielectric constant of 2.5 at 1 MHz and a dielectric strength of 500 V/mil.
  compare: In low Earth orbit ECTFE eroded at 1.79e-24 cm3/atom on the MISSE 2 flight, about the same as Kapton H at 3.00e-24 and far faster than PTFE (1.42e-25 cm3/atom) at 1.42e-25. For strength, a data sheet gives a tensile strength of 7000 psi for ECTFE and 8000 psi for a supplier's Halar 901 rod, and an elongation at break of 200 percent.
  handling:
    - Keep the material away from heat and ignition sources, and never overheat it.
    - Provide local ventilation suited to the decomposition risk, and avoid fume inhalation.
    - Use breathing apparatus with a face mask if decomposition occurs.
    - Take measures against static build-up when handling it.
  good_for:
    - Chemical linings and pipes. The data sheet says it resists most acids, alkalines and solvents.
    - Tough, impact-resistant parts. The data sheet gives an elongation at break of 200 percent and a tensile strength of 7000 psi.
    - Tough cable jackets with a continuous range of -76 °C to +150 °C.
    - Low water absorption, below 0.1 percent over 24 hours.
  watch_out:
    - Atomic oxygen. On the MISSE 2 flight ECTFE eroded far faster than PTFE (1.42e-25 cm3/atom).
    - Overheating. Above about 350 °C ECTFE releases hydrogen fluoride and other toxic gases.
    - Permeation. Small molecules such as water and HF permeate the matrix and can limit a lining's lifetime.
    - Hot amines and ketones attack it, according to the data sheet.
  verdict: ECTFE is a tough, chemically resistant fluoropolymer that is a good choice for linings, pipes and cable jackets on the ground. In low Earth orbit it erodes at about the same rate as Kapton H, so it is a poor choice for an exposed surface there. The flight erosion yield is the only space result here; the strength, density and electrical values are data-sheet typical values.
  compare_rows:
    - label: Density
      benchmark: density
      scope: material
    - label: Max service temp
      benchmark: max_service_temp
      scope: material
    - label: Melting point
      benchmark: melting_point
      scope: material