spore: profile
id: pom-delrin
spore_version: 0.2
family: engineering-polymers
name: Polyoxymethylene (acetal), POM
abbreviation: POM
role: engineering thermoplastic for precision moulded parts; Delrin is a DuPont trade name for POM
category: polymers
type: acetals
summary: |
  Polyoxymethylene (POM), also called acetal and sold as Delrin, is a semicrystalline engineering thermoplastic sold as a homopolymer or a copolymer. Two Celanese Hostaform copolymer grades read for this profile have a density of 1410 kg/m3 (ISO 1183), a melting temperature of 165 °C (C 2521) and 166 °C (C 13021 FC) at 10 °C/min, and a tensile modulus of 2600 MPa (C 2521) and 2700 MPa (C 13021 FC). As a sample on the MISSE 2 experiment in low Earth orbit it had an atomic oxygen erosion yield of 9.14e-24 cm3/atom (NASA TM-2008-215490, Table I). No homopolymer Delrin datasheet was read in this run.
best_for: 'Stiff, dimensionally stable moulded parts: a 2700 MPa tensile modulus and 64 MPa yield stress in the C 13021 FC copolymer grade'
weakest_at: 'Atomic oxygen in low Earth orbit: an erosion yield of 9.14e-24 cm3/atom on MISSE 2'
identity:
  name: Polyoxymethylene (acetal), POM (Delrin)
  formula: CH2O (smallest repeat unit as listed by NASA)
  source: nasa-tm-2008-215490
  where: Table IV, column Formula
tags:
  environments:
    - low-earth-orbit
  stresses:
    - atomic-oxygen
    - vacuum-and-outgassing
  applications: []
properties:
  - benchmark: density
    label: Density, Hostaform C 2521 (copolymer)
    value: 1410
    unit: kg/m3
    scope: material
    conditions:
      grade: Hostaform C 2521, POM copolymer
      temperature: not printed on the page
    method: ISO 1183, as printed on the Material Data Center datasheet
    status: ground
    source: mdc-hostaform-c2521
    where: Datasheet table, row Density (Other properties)
  - benchmark: melting_point
    label: Melting temperature, Hostaform C 2521 (copolymer)
    value: 165
    unit: °C
    scope: material
    conditions:
      grade: Hostaform C 2521, POM copolymer
      rate: 10 °C/min
    method: ISO 11357-1/-3 (DSC), as printed on the datasheet
    status: ground
    source: mdc-hostaform-c2521
    where: Datasheet table, row Melting temperature, 10°C/min
  - benchmark: tensile_modulus
    label: Tensile modulus, Hostaform C 2521 (copolymer)
    value: 2600
    unit: MPa
    scope: material
    conditions:
      grade: Hostaform C 2521, POM copolymer
      test: ISO 527 as printed
    method: ISO 527, as printed on the datasheet
    status: ground
    source: mdc-hostaform-c2521
    where: Datasheet table, row Tensile Modulus
  - benchmark: tensile_yield_strength
    label: Yield stress, Hostaform C 2521 (copolymer)
    value: 62
    unit: MPa
    scope: material
    conditions:
      grade: Hostaform C 2521, POM copolymer
      test: ISO 527 as printed
    method: ISO 527, as printed on the datasheet
    status: ground
    source: mdc-hostaform-c2521
    where: Datasheet table, row Yield stress
  - benchmark: nominal_strain_at_break
    label: Nominal strain at break, Hostaform C 2521 (copolymer)
    value: 32
    unit: '%'
    scope: material
    conditions:
      grade: Hostaform C 2521, POM copolymer
      test: ISO 527 as printed
    method: ISO 527, as printed on the datasheet
    status: ground
    source: mdc-hostaform-c2521
    where: Datasheet table, row Nominal strain at break
  - benchmark: charpy_notched_impact
    label: Charpy notched impact strength at +23 °C, Hostaform C 2521
    value: 8.5
    unit: kJ/m2
    scope: material
    conditions:
      grade: Hostaform C 2521, POM copolymer
      temperature: +23 °C
      notch: type A, as printed
    method: ISO 179/1eA, as printed on the datasheet
    status: ground
    source: mdc-hostaform-c2521
    where: Datasheet table, row Charpy notched impact strength, +23°C
  - benchmark: heat_deflection_temperature
    label: Temperature of deflection under load (HDT), Hostaform C 2521
    value: 101
    unit: °C
    scope: material
    conditions:
      grade: Hostaform C 2521, POM copolymer
      load: 1.80 MPa
    method: ISO 75-1/-2, as printed on the datasheet
    status: ground
    source: mdc-hostaform-c2521
    where: Datasheet table, row Temp. of deflection under load, 1.80 MPa (HDT)
  - benchmark: density
    label: Density, Hostaform C 13021 FC (copolymer)
    value: 1410
    unit: kg/m3
    scope: material
    conditions:
      grade: Hostaform C 13021 FC, POM copolymer
      temperature: not printed on the page
    method: ISO 1183, as printed on the Material Data Center datasheet
    status: ground
    source: mdc-hostaform-c13021fc
    where: Datasheet table, row Density (密度)
  - benchmark: melting_point
    label: Melting temperature, Hostaform C 13021 FC (copolymer)
    value: 166
    unit: °C
    scope: material
    conditions:
      grade: Hostaform C 13021 FC, POM copolymer
      rate: 10 °C/min
    method: ISO 11357-1/-3 (DSC), as printed on the datasheet
    status: ground
    source: mdc-hostaform-c13021fc
    where: Datasheet table, row Melting temperature, 10°C/min
  - benchmark: tensile_modulus
    label: Tensile modulus, Hostaform C 13021 FC (copolymer)
    value: 2700
    unit: MPa
    scope: material
    conditions:
      grade: Hostaform C 13021 FC, POM copolymer
      test: ISO 527 as printed
    method: ISO 527, as printed on the datasheet
    status: ground
    source: mdc-hostaform-c13021fc
    where: Datasheet table, row Tensile modulus (拉伸模量)
  - benchmark: tensile_yield_strength
    label: Yield stress, Hostaform C 13021 FC (copolymer)
    value: 64
    unit: MPa
    scope: material
    conditions:
      grade: Hostaform C 13021 FC, POM copolymer
      test: ISO 527 as printed
    method: ISO 527, as printed on the datasheet
    status: ground
    source: mdc-hostaform-c13021fc
    where: Datasheet table, row Yield stress (屈服应力)
  - benchmark: nominal_strain_at_break
    label: Nominal strain at break, Hostaform C 13021 FC (copolymer)
    value: 30
    unit: '%'
    scope: material
    conditions:
      grade: Hostaform C 13021 FC, POM copolymer
      test: ISO 527 as printed
    method: ISO 527, as printed on the datasheet
    status: ground
    source: mdc-hostaform-c13021fc
    where: Datasheet table, row Nominal strain at break (名义断裂伸长率)
  - benchmark: charpy_notched_impact
    label: Charpy notched impact strength at +23 °C, Hostaform C 13021 FC
    value: 6
    unit: kJ/m2
    scope: material
    conditions:
      grade: Hostaform C 13021 FC, POM copolymer
      temperature: +23 °C
      notch: type A, as printed
    method: ISO 179/1eA, as printed on the datasheet
    status: ground
    source: mdc-hostaform-c13021fc
    where: Datasheet table, row Charpy impact, +23°C (简支梁缺口冲击强度)
  - benchmark: atomic_oxygen_erosion_yield
    label: Atomic oxygen erosion yield, POM (MISSE 2)
    value: 9.14e-24
    unit: cm3/atom
    scope: material
    conditions:
      platform: ISS, MISSE 2 PEC 2 tray 1, low Earth orbit
      fluence: 8.43e21 atoms/cm2
      duration: 3.95 years
    method: Measured on MISSE 2 flight samples and listed in NASA TM-2008-215490
    status: flight
    source: nasa-tm-2008-215490
    where: Table I, MISSE 2 PEACE polymers erosion yield data (passport misse2-pom-delrin)
  - benchmark: density
    label: Density, Delrin 500P NC010 (homopolymer)
    value: 1.42
    unit: g/cm³
    scope: material
    conditions:
      grade: Delrin 500P NC010, POM homopolymer
      temperature: not printed
    method: ISO 1183, as printed on the DuPont datasheet
    status: ground
    source: dupont-delrin-500p
    where: Physical table, row Density
  - benchmark: melting_point
    label: Melting temperature, Delrin 500P NC010 (homopolymer)
    value: 178
    unit: °C
    scope: material
    conditions:
      grade: Delrin 500P NC010, POM homopolymer
    method: ISO 11357-3, as printed on the datasheet
    status: ground
    source: dupont-delrin-500p
    where: Thermal table, row Melting Temperature
  - benchmark: tensile_modulus
    label: Tensile modulus, Delrin 500P NC010 (homopolymer)
    value: 3100
    unit: MPa
    scope: material
    conditions:
      grade: Delrin 500P NC010, POM homopolymer
      test: ISO 527-2 as printed
    method: ISO 527-2, as printed on the datasheet
    status: ground
    source: dupont-delrin-500p
    where: Mechanical table, row Tensile Modulus
  - benchmark: tensile_yield_strength
    label: Tensile stress at yield, Delrin 500P NC010 (homopolymer)
    value: 71
    unit: MPa
    scope: material
    conditions:
      grade: Delrin 500P NC010, POM homopolymer
      test: ISO 527-2 as printed
    method: ISO 527-2, as printed on the datasheet
    status: ground
    source: dupont-delrin-500p
    where: Mechanical table, row Tensile Stress (Yield)
  - benchmark: nominal_strain_at_break
    label: Nominal tensile strain at break, Delrin 500P NC010 (homopolymer)
    value: 30
    unit: '%'
    scope: material
    conditions:
      grade: Delrin 500P NC010, POM homopolymer
      test: ISO 527-2 as printed
    method: ISO 527-2, as printed on the datasheet
    status: ground
    source: dupont-delrin-500p
    where: Mechanical table, row Nominal Tensile Strain at Break
  - benchmark: flexural_modulus
    label: Flexural modulus, Delrin 500P NC010 (homopolymer)
    value: 3000
    unit: MPa
    scope: material
    conditions:
      grade: Delrin 500P NC010, POM homopolymer
    method: ISO 178, as printed on the datasheet
    status: ground
    source: dupont-delrin-500p
    where: Mechanical table, row Flexural Modulus
  - benchmark: charpy_notched_impact
    label: Charpy notched impact strength at 23 °C, Delrin 500P NC010 (homopolymer)
    value: 9
    unit: kJ/m2
    scope: material
    conditions:
      grade: Delrin 500P NC010, POM homopolymer
      temperature: 23 °C (73 °F)
      notch: type A, ISO 179/1eA
    method: ISO 179/1eA, as printed on the datasheet
    status: ground
    source: dupont-delrin-500p
    where: Impact table, Charpy Notched Impact Strength, 73°F (23°C) row
  - benchmark: heat_deflection_temperature
    label: Heat deflection temperature at 1.8 MPa (unannealed), Delrin 500P NC010
    value: 95
    unit: °C
    scope: material
    conditions:
      grade: Delrin 500P NC010, POM homopolymer
      load: 264 psi (1.8 MPa), unannealed
    method: ISO 75-2/A, as printed on the datasheet
    status: ground
    source: dupont-delrin-500p
    where: Thermal table, Heat Deflection Temperature, 264 psi (1.8 MPa), Unannealed row
  - benchmark: vicat_softening_temperature
    label: Vicat softening temperature, Delrin 500P NC010
    value: 155
    unit: °C
    scope: material
    conditions:
      grade: Delrin 500P NC010, POM homopolymer
      method_load: ISO 306/B50
    method: ISO 306/B50, as printed on the datasheet
    status: ground
    source: dupont-delrin-500p
    where: Thermal table, row Vicat Softening Temperature
  - benchmark: cte
    label: Coefficient of linear thermal expansion, flow direction, Delrin 500P NC010
    value: 0.0001
    unit: cm/cm/°C
    scope: material
    conditions:
      grade: Delrin 500P NC010, POM homopolymer
      direction: flow
    method: ISO 11359-2, as printed on the datasheet (printed as 1.0E-4 cm/cm/°C)
    status: ground
    source: dupont-delrin-500p
    where: Thermal table, CLTE, Flow row (SI column)
corrosion:
  - environment: Chlorine gas and bleaching fluid
    headline: Chlorine attacks acetal at 3 to 5 ppm and higher, so long-term continuous exposure is not recommended.
    effect: DuPont states that DELRIN acetal resin is attacked by chlorine at concentrations of 3 to 5 ppm and higher, and is not recommended for long term continuous exposure at these concentrations. Its rating table marks chlorine gas and 10 percent bleaching fluid as unsatisfactory.
    rating: severe
    conditions:
      basis: unstressed specimens in continuous exposure; rating table at ambient temperature
    source: dupont-delrin-design-guide
    where: 'Chapter 7 (Effects), Resistance to chemicals: zinc chloride and chlorine section; rating table'
  - environment: Zinc chloride, and salt water in contact with zinc-plated steel
    headline: Zinc chloride depolymerises acetal; salt water alone does not affect it.
    effect: DuPont says zinc chloride acts to depolymerise (corrode) DELRIN acetal resin, with attack depending on stress, temperature, concentration and time. Salt water alone does not affect it, but salt water with zinc-plated steel can give a slower effect similar to zinc chloride.
    rating: moderate
    conditions:
      basis: stress, temperature, concentration and time are not quantified in the guide
    source: dupont-delrin-design-guide
    where: 'Chapter 7 (Effects), Resistance to chemicals: zinc chloride and chlorine section'
  - environment: Strong acids and strong bases; steam and hot water
    headline: Service life is reduced by lengthy use in steam, hot water, strong acids or strong bases.
    effect: DuPont lists steam, hot water, strong acids and strong bases as reducing service life. Its rating table marks hydrochloric acid (10 percent), sulphuric acid (30 percent), nitric acid (10 percent), perchloric acid (10 percent) and phosphoric acid (30 percent) as unsatisfactory, and acetic acid (5 percent) as resistant.
    rating: moderate
    conditions:
      basis: unstressed specimens at ambient temperature; the guide says intermittent exposure and service stresses can change the result
    source: dupont-delrin-design-guide
    where: Introduction, service life statement; Chapter 7 rating table
  - environment: Hot water and strong caustic or high pH solutions, copolymer against homopolymer
    headline: Copolymer acetal resists hot water and strong caustics better than homopolymer, per Alro.
    effect: Alro lists better resistance to hot water and strong caustics, or high pH solutions, as an advantage of acetal copolymer over homopolymer. No temperature, concentration or time is printed.
    rating: low
    conditions:
      basis: comparison of copolymer and homopolymer, no test figures printed
    source: alro-acetal-catalog
    where: Acetal section, list of advantages of copolymer over homopolymer
  - environment: Sunlight UV (290 to 400 nm), outdoors and through glass
    headline: Acetal is affected by sunlight; UV-stabilised grades are offered for outdoor and glass-behind use.
    effect: DuPont says acetal resins, like most polymers, are affected by light, particularly sunlight with ultraviolet radiation of 290 to 400 nm. It lists UV-stabilised grades (for example DELRIN 127UV, 527UV and 927UV) with excellent UV resistance and thermal stability, and says the x27UV series suits parts exposed to sunlight through glass. No retention figure is printed.
    rating: moderate
    conditions:
      wavelength: 290 to 400 nm
      basis: grade dependent; no dose or retention figure printed
    source: dupont-delrin-design-guide
    where: Chapter 7 (Effects), Weathering section; grade list
  - environment: Gamma radiation
    headline: DuPont gives depolymerisation as the predominant degradation mode under gamma ray dosage.
    effect: DuPont says that the predominant mode of degradation resulting from gamma ray dosage is depolymerisation. The guide prints no dose figure in the text read.
    rating: moderate
    conditions:
      dose: not printed in the text read
    source: dupont-delrin-design-guide
    where: Chapter 7 (Effects), Exposure to high energy radiation section
  - environment: Unstressed exposure in air at 60 C, long term
    headline: DELRIN 500 keeps a tensile strength above 55 MPa for about 5 years at 60 C.
    effect: DuPont's long-term exposure curve for unstressed injection-moulded bars in air says DELRIN 500 would keep a tensile strength in excess of 55 MPa for approximately 5 years at 60 C.
    rating: low
    conditions:
      temperature: 60 C
      stress: none, unstressed
      grade: DELRIN 500
    source: dupont-delrin-design-guide
    where: Chapter 7 (Effects), Exposure in air at elevated temperature, Figure 7.02 text
  - environment: 'Fuels: M-15 gasoline (15 percent methanol) and diesel at 60 C'
    headline: Standard grades change only slightly after 1500 h in M-15 and hardly at all in diesel.
    effect: DuPont aged DELRIN 500 and 500P NC010 for up to 1500 hours at 60 C in M-15, and reports only small changes from slight plastification by fuel absorption. In diesel, bio-diesel and kerosene it reports almost no change in dimensional or mechanical properties after 2000 hours at 60 C.
    rating: low
    conditions:
      temperature: 60 C
      time: up to 1500 h in M-15; up to 2000 h in diesel
      fuel: M-15 is regular gasoline with 15 percent methanol
    source: dupont-delrin-design-guide
    where: 'Chapter 7 (Effects), Resistance to chemicals: fuels section; Figure 7.01'
risks:
  hazards:
    - text: 'Formaldehyde (CAS 50-00-0), the monomer POM is made from. PubChem aggregated GHS: Danger, with H302 harmful if swallowed, H314 causes severe skin burns and eye damage, H317 may cause an allergic skin reaction, H330 fatal if inhaled, H341 suspected of causing genetic defects and H350 may cause cancer. The POM polymer itself has no GHS entry in PubChem.'
      ghs:
        - H302
        - H314
        - H317
        - H330
        - H341
        - H350
      source: pubchem-formaldehyde
      where: Safety and Hazards, GHS Classification (aggregated, CID 712)
  failure_risks:
    - mode: Atomic oxygen erosion in low Earth orbit
      trigger: Exposure of a POM part to atomic oxygen in low Earth orbit, as on the MISSE 2 flight
      consequence: Surface erosion at a yield of 9.14e-24 cm3/atom as measured on MISSE 2
      severity: moderate
      source: nasa-tm-2008-215490
      where: Table I
    - mode: Chlorine attack
      trigger: Chlorine gas or bleach at 3 to 5 ppm and higher, in long-term continuous exposure
      consequence: Attack on the acetal; DuPont rates chlorine gas and 10 percent bleaching fluid as unsatisfactory
      severity: critical
      source: dupont-delrin-design-guide
      where: Chapter 7, Zinc chloride and chlorine; rating table
    - mode: Zinc chloride depolymerisation
      trigger: Zinc chloride, or salt water in contact with zinc-plated steel
      consequence: Depolymerisation (corrosion) of the acetal, depending on stress, temperature, concentration and time
      severity: moderate
      source: dupont-delrin-design-guide
      where: Chapter 7, Zinc chloride and chlorine
    - mode: Strong acid or strong base attack
      trigger: Lengthy use in strong acids or strong bases, or in steam and hot water
      consequence: Shorter service life; DuPont rates hydrochloric, sulphuric, nitric and phosphoric acids at 10 to 30 percent as unsatisfactory
      severity: moderate
      source: dupont-delrin-design-guide
      where: Introduction, service life statement; Chapter 7 rating table
    - mode: UV degradation in sunlight
      trigger: Sunlight UV at 290 to 400 nm on standard grades, outdoors or through glass
      consequence: Light-induced degradation; UV-stabilised grades are offered for this exposure
      severity: moderate
      source: dupont-delrin-design-guide
      where: Chapter 7, Weathering section
    - mode: Gamma radiation depolymerisation
      trigger: Gamma ray dosage
      consequence: DuPont gives depolymerisation as the predominant degradation mode
      severity: moderate
      source: dupont-delrin-design-guide
      where: Chapter 7, Exposure to high energy radiation
  side_effects: []
  handling:
    - text: Keep chlorine, bleach and chlorinated water away from stressed parts. DuPont does not recommend long-term continuous exposure at 3 to 5 ppm chlorine and above.
      source: dupont-delrin-design-guide
      where: Chapter 7, Zinc chloride and chlorine
    - text: Use local extraction where heating or processing may release formaldehyde; the formaldehyde GHS codes above are the reason. No POM-specific release figure was read.
      source: pubchem-formaldehyde
      where: Safety and Hazards, GHS Classification
  mitigations:
    - text: For sunlight exposure, choose a UV-stabilised grade such as DELRIN 127UV, 527UV or 927UV, per the DuPont grade list.
      source: dupont-delrin-design-guide
      where: Grade list
    - text: For hot water or strong caustic service, choose a copolymer grade, which Alro says resists these better than homopolymer.
      source: alro-acetal-catalog
      where: Acetal section, copolymer advantages
uses:
  - application: mechanisms
    device: Gears and drive trains
    example: DuPont lists DELRIN 100 for high performance engineering parts such as gears, and DELRIN 500CL for gears, drive trains and sliding devices. Alro lists gears and pulleys among its acetal applications.
    source: dupont-delrin-design-guide
    where: Grade list, DELRIN 100 and DELRIN 500CL rows
  - application: mechanisms
    device: Zippers and thin-section parts
    example: DuPont lists DELRIN 900P, a low-viscosity grade for thin sections, for consumer electronics parts and zippers.
    source: dupont-delrin-design-guide
    where: Grade list, DELRIN 900P row
  - application: structures
    device: Fasteners and snap-fits
    example: DuPont lists DELRIN 500 for general mechanical parts, automotive fuel systems, snap-fits, fasteners and gears, and DELRIN 100T for fasteners, seat belt restraint systems and gears.
    source: dupont-delrin-design-guide
    where: Grade list, DELRIN 500 and DELRIN 100T rows
supply:
  - subject: Formaldehyde, the feedstock for POM
    routes: PubChem states that formaldehyde is prepared commercially by catalytic vapour-phase oxidation of methanol with air, over heated silver, copper, alumina or coke, and that the silver, copper or iron-molybdenum oxide processes are the widely used ones. It also states that all of the world's commercial formaldehyde is made from methanol and air by a metal or metal-oxide catalyst process.
    producers: []
    critical_lists: []
    source: pubchem-formaldehyde
    where: Methods of Manufacturing
  - subject: POM resin, made by polymerisation of formaldehyde
    routes: DuPont says acetal is made by the polymerization of formaldehyde. Celanese developed the copolymer route, which Polyplastics (Daicel) marketed as DURACON from 1964.
    producers:
      - name: Polyplastics (Daicel)
        note: DURACON polyacetal. Founded in 1964 as a joint venture with Celanese; Daicel made it a wholly owned subsidiary in October 2020.
        country: Polyplastics (Daicel)
      - name: Celanese
        note: Hostaform copolymer grades, as printed on the Material Data Center datasheets read for this profile.
        country: Celanese
      - name: DuPont
        note: Delrin homopolymer, as printed on the DuPont Delrin 500P NC010 datasheet read for this profile.
        country: DuPont
    critical_lists: []
    source: daicel-history
    where: Corporate history, 1964 and October 2020 entries
documents:
  - title: Hostaform C 2521, Material Data Center datasheet
    type: datasheet
    url: https://materialdatacenter.com/ms/en/Hostaform/Celanese/HOSTAFORM%C2%AE+C+2521/e3040fc5/2434
  - title: Hostaform C 13021 FC, Material Data Center datasheet
    type: datasheet
    url: https://materialdatacenter.com/ms/zh/Hostaform/Celanese/HOSTAFORM%C2%AE+C+13021+FC/9f8f323b/2434
  - title: Polyoxymethylene, Wikipedia
    type: report
    url: https://en.wikipedia.org/wiki/Polyoxymethylene
  - title: Delrin 500P NC010, DuPont technical data sheet (PDF, via Protolabs)
    type: datasheet
    url: https://Protolabs.com/media/1022598/delrin-500p_nc010.pdf
  - title: Banks, Backus and de Groh, Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit, NASA/TM-2008-215490
    type: report
    url: https://ntrs.nasa.gov/citations/20090011780
    year: 2008
  - title: PubChem, Formaldehyde CID 712 (GHS and manufacture)
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/712
  - title: DELRIN acetal resin design information, DuPont
    type: datasheet
    url: https://www.spacematdb.com/spacemat/manudatasheets/Delrin%20design%20info.pdf
  - title: Delrin acetal homopolymer technical data sheet
    type: datasheet
    url: https://laminatedplastics.com/delrin.pdf
  - title: Alro Plastics acetal section
    type: datasheet
    url: https://www.alro.com/Resources/WebResources/AlroCom/PlasticsReferanceCatalog/PDFs/002-Acetals.pdf
  - title: DAICEL corporate history
    type: report
    url: https://www.daicel.com/en/corporate/history/
gaps:
  - Delrin 500P NC010 values are from a DuPont datasheet PDF hosted by Protolabs (not the DuPont site); the Nordson-hosted and plasticker copies seen in search were not read, so their different figures are not used.
  - 'Supply volumes: no POM or formaldehyde production volume or country share was read. Producer names come from the Daicel history page and the Material Data Center datasheets. Asahi Kasei, BASF, Mitsubishi Gas Chemical and others named in market-report snippets are not verified and are not listed.'
  - 'Ageing: no temperature, rate or formaldehyde figure for thermal degradation of POM was read. The DuPont guide names depolymerisation only for zinc chloride and gamma dose.'
  - 'Corrosion: DuPont gives qualitative ratings and some time-based data only. The Celanese Hostaform product manual and Celcon design guide returned HTML rather than readable PDF, so no Celanese chemical table is used.'
  - 'Hazards: PubChem has no record for polyoxymethylene. Lookups by name and by CAS 9002-81-7 returned not found, so no POM GHS entry is recorded. The hazards above are for formaldehyde.'
  - 'Uses: only DuPont grade-list uses and one Alro line are recorded. No sourced use for POM in space was read.'
  - No Delrin homopolymer grade other than 500P NC010 has a datasheet value in this profile. The DuPont design guide and Delrin technical data sheet give qualitative statements for other grades.
  - Flexural modulus, HDT and Izod impact are not printed on the C 13021 FC datasheet read, and flexural modulus is not printed on C 2521.
  - No outgassing, total mass loss, UV, radiation or thermal-cycling result for POM in space was read; the passport lists these stresses but gives no values for them.
  - Test conditions and standards are as printed on the Material Data Center pages; the Celanese originals were not reached.
sources:
  wiki-pom:
    title: Polyoxymethylene, Wikipedia (composition and history only)
    id: Wikipedia article Polyoxymethylene
    url: https://en.wikipedia.org/wiki/Polyoxymethylene
    kind: web
    license: CC BY-SA 4.0
    where: 'Copolymer section: the copolymer replaces about 1–1.5% of the –CH2O– groups with –CH2CH2O–'
  dupont-delrin-500p:
    title: Delrin 500P NC010, DuPont Performance Polymers technical data sheet
    id: DuPont Delrin 500P NC010 product data sheet, hosted by Protolabs
    url: https://Protolabs.com/media/1022598/delrin-500p_nc010.pdf
    kind: datasheet
    license: manufacturer datasheet, linked not reproduced
  mdc-hostaform-c2521:
    title: Hostaform C 2521, Material Data Center typical properties
    id: Material Data Center trade name entry, Celanese Hostaform C 2521
    url: https://materialdatacenter.com/ms/en/Hostaform/Celanese/HOSTAFORM%C2%AE+C+2521/e3040fc5/2434
    kind: database
    license: third-party database page, linked not reproduced
  mdc-hostaform-c13021fc:
    title: Hostaform C 13021 FC, Material Data Center typical properties
    id: Material Data Center trade name entry, Celanese Hostaform C 13021 FC
    url: https://materialdatacenter.com/ms/zh/Hostaform/Celanese/HOSTAFORM%C2%AE+C+13021+FC/9f8f323b/2434
    kind: database
    license: third-party database page, linked not reproduced
  nasa-tm-2008-215490:
    title: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit
    id: NASA/TM-2008-215490 (Banks, Backus and de Groh, 2008), NTRS 20090011780
    url: https://ntrs.nasa.gov/citations/20090011780
    year: 2008
    kind: report
    license: NASA public document
  pubchem-formaldehyde:
    title: 'Formaldehyde (CID 712), PubChem compound record: GHS classification and methods of manufacture'
    id: PubChem CID 712, formaldehyde, CAS 50-00-0 (read via the PubChem REST pug_view API)
    url: https://pubchem.ncbi.nlm.nih.gov/compound/712
    kind: database
    license: public database record, linked not reproduced
  dupont-delrin-design-guide:
    title: DELRIN acetal resin design information, DuPont (chemical resistance, weathering, grade list)
    id: DuPont DELRIN design information PDF, hosted at spacematdb.com
    url: https://www.spacematdb.com/spacemat/manudatasheets/Delrin%20design%20info.pdf
    kind: handbook
    license: manufacturer design guide, linked not reproduced
  delrin-tds-laminatedplastics:
    title: Delrin (acetal homopolymer) POM technical data sheet
    id: Delrin acetal homopolymer technical data sheet, hosted on laminatedplastics.com
    url: https://laminatedplastics.com/delrin.pdf
    kind: datasheet
    license: manufacturer datasheet, linked not reproduced
  alro-acetal-catalog:
    title: Acetal copolymer and homopolymer, Alro Plastics catalogue section
    id: Alro Plastics plastics reference catalogue, acetal section (PDF)
    url: https://www.alro.com/Resources/WebResources/AlroCom/PlasticsReferanceCatalog/PDFs/002-Acetals.pdf
    kind: web
    license: distributor catalogue, linked not reproduced
  daicel-history:
    title: 'DAICEL corporate history: Polyplastics joint venture (1964) and wholly owned subsidiary (2020)'
    id: DAICEL company history page
    url: https://www.daicel.com/en/corporate/history/
    kind: web
    license: company web page, linked not reproduced
license: CC-BY-4.0
updated: '2026-10-18'
review:
  status: draft
  method: assistant
  checked_values: 24
  unreachable: 4
  caveats: 5
  note: 'Values were read by an AI assistant on 2026-10-18. The two copolymer grades were read from Material Data Center pages (third-party, not Celanese originals). The erosion yield was copied from the passport misse2-pom-delrin, which was verified by hand. Unreachable: Delrin 500P, 500T and 500CPE pages on Material Data Center (404), Celanese datasheets (403/404), CURBELL acetal page (403). Caveats: no Delrin homopolymer value is recorded; the copolymer values are for Hostaform grades, not Delrin; the erosion yield is for one flight sample; source count is 10 (see sources).'
story:
  recipe:
    line: Polyoxymethylene is a chain of repeating CH2O units, made from formaldehyde. The homopolymer is end-capped to stabilise it; the copolymer contains about 1 to 1.5 percent CH2CH2O units along the chain (Wikipedia, composition only; key wiki-pom).
    parts:
      - name: Carbon
        symbol: C
        atoms: 1
        atomic_weight: 12.011
        role: One carbon per CH2O repeat unit, part of the backbone.
      - name: Hydrogen
        symbol: H
        atoms: 2
        atomic_weight: 1.008
        role: Two hydrogens per CH2O repeat unit.
      - name: Oxygen
        symbol: O
        atoms: 1
        atomic_weight: 15.999
        role: One ether oxygen per CH2O repeat unit, joining the backbone.
  risk_groups:
    - title: For people
      lead: POM has no GHS entry in PubChem; the hazard here is formaldehyde, the monomer it is made from.
      level: 1
      verdict: Formaldehyde hazard
      points:
        - label: Classification
          line: Formaldehyde carries H302, H314, H317, H330, H341 and H350 (PubChem aggregated). Chlorine and strong acids are a corrosion risk for parts, not a listed hazard for people.
    - title: If it fails
      lead: The failure route in these sources is erosion in orbit, measured on one flight sample.
      points:
        - label: Atomic oxygen
          line: On MISSE 2 the erosion yield was 9.14e-24 cm3/atom, from the same NASA report.
  uses:
    - where: Gears and drive trains
      line: DuPont lists DELRIN 100 for gears and DELRIN 500CL for gears, drive trains and sliding devices.
    - where: Zippers and thin-section parts
      line: DuPont lists DELRIN 900P, a low-viscosity grade for thin sections, for consumer electronics parts and zippers.
    - where: Fasteners and snap-fits
      line: DuPont lists DELRIN 500 for snap-fits, fasteners and gears, and DELRIN 100T for fasteners and seat belt systems.
  why: Polyoxymethylene is a semicrystalline engineering thermoplastic. The two Hostaform copolymer grades read here have a density of 1410 kg/m3 and melting temperatures of 165 °C (C 2521) and 166 °C (C 13021 FC) at 10 °C/min. Their tensile moduli are 2600 MPa and 2700 MPa.
  can_do:
    - label: Stiff moulding grade
      value: 2700 MPa tensile modulus
      benchmark: tensile_modulus
      line: Hostaform C 13021 FC has a tensile modulus of 2700 MPa and a yield stress of 64 MPa under ISO 527, as printed on its datasheet page.
    - label: Heat under load
      value: 101 °C HDT at 1.80 MPa
      benchmark: heat_deflection_temperature
      line: Hostaform C 2521 has a temperature of deflection under load of 101 °C at 1.80 MPa, ISO 75-1/-2, as printed on its datasheet page.
    - label: Survive in orbit
      value: 9.14e-24 cm3/atom
      benchmark: atomic_oxygen_erosion_yield
      line: NASA lists a MISSE 2 erosion yield for polyoxymethylene of 9.14e-24 cm3/atom, in Table I.
  compare: The two grades are read from one database, so compare the rows as examples for these two Hostaform grades, not as a ranking of all POM.
  compare_rows:
    - scope: material
      label: Density
      benchmark: density
    - scope: material
      label: Melting temperature
      benchmark: melting_point
    - scope: material
      label: Tensile modulus
      benchmark: tensile_modulus
  handling:
    - 'Specify the grade: the two copolymer grades read differ in modulus and melting temperature.'
    - Treat the datasheet values as typical values as printed, not as specification limits.
  good_for:
    - 'Stiff moulded parts: 2700 MPa tensile modulus and 64 MPa yield stress in Hostaform C 13021 FC, as printed.'
    - 'Known atomic oxygen behaviour: 9.14e-24 cm3/atom on MISSE 2 in low Earth orbit.'
  watch_out:
    - Atomic oxygen erodes POM at 9.14e-24 cm3/atom, so exterior use needs protection or a rate allowance.
    - No Delrin homopolymer value was read, so the numbers here are for copolymer grades only.
    - Flexural modulus and Izod impact were not found on the datasheets read.
  verdict: 'Polyoxymethylene is a stiff engineering plastic: the two copolymer grades read have a density of 1410 kg/m3, a melting temperature of 165 to 166 °C, and a tensile modulus of 2600 to 2700 MPa. Its MISSE 2 erosion yield of 9.14e-24 cm3/atom is recorded, and no homopolymer Delrin data is in this profile yet.'