spore: profile
id: ca
spore_version: 0.2
family: engineering-polymers
name: Cellulose acetate
abbreviation: CA
role: bioplastic film base, eyeglass frame and fibre material
category: polymers
type: cellulosics
summary: |
  Cellulose acetate (CA) is a cellulose ester made by acetylating wood pulp or cotton linters. The Eastman CA-398-3 grade read for this profile has an acetyl content of 39.8 wt %, a glass transition of 180 °C, and a specific gravity of 1.31. As a sample on the NASA MISSE 2 PEACE tray in low Earth orbit it had an atomic oxygen erosion yield of 5.05e-24 cm3/atom, close to the 5.06e-24 cm3/atom that the NASA predictive tool gave for it. The film base was once the standard for photographic film before polyester replaced it.
best_for: 'Stiff, clear film and moulding compound from a cellulose ester: a glass transition of 180 °C in the Eastman CA-398-3 grade, and a flight-measured erosion yield of 5.05e-24 cm3/atom in low Earth orbit for predicting similar esters'
weakest_at: 'Heat and moisture: the Eastman SDS prints a decomposition temperature of 304 °C, sources say CA releases acetic acid when heat or moisture act on film, and it erodes in low Earth orbit at 5.05e-24 cm3/atom'
identity:
  formula: Cellulose acetate, repeat unit C12H16O8 as printed in NASA TM-2008-215490 Table IV (a triacetate-type formula; the Eastman CA-398-3 grade is printed at 39.8 wt % acetyl)
  cas: 9004-35-7
  source: eastman-sds-ca398-3
  where: Section 3 (cellulose acetate, CAS-No. 9004-35-7, 100 % w/w); NASA TM-2008-215490 Table IV (formula C12H16O8, atomic mass 288.2536 g/mole)
tags:
  environments:
    - low-earth-orbit
  stresses:
    - atomic-oxygen
    - uv
    - thermal-cycling
  applications:
    - optics-and-cameras
    - electronics-and-chips
properties:
  - benchmark: density
    label: Density, MISSE 2 PEACE polymers table
    value: 1.2911
    unit: g/cm3
    scope: material
    conditions:
      basis: ref. 12 density measurement, as printed in NASA Table II
    method: Density measured for the MISSE 2 PEACE polymer set and listed in NASA TM-2008-215490 Table II; no test standard printed
    status: ground
    source: nasa-tm-2008-215490
    where: Table II (MISSE 2 PEACE polymers density and fractional ash content), row Cellulose acetate, CA
  - benchmark: atomic_oxygen_erosion_yield
    label: Atomic oxygen erosion yield, cellulose acetate (MISSE 2)
    value: 5.05e-24
    unit: cm3/atom
    scope: material
    conditions:
      platform: ISS, MISSE 2 PEACE, low Earth orbit
      fluence: 8.43e21 atoms/cm2 over a 4 year exposure, as printed in the report text
      table: Table I, MISSE 2 PEACE polymers erosion yield data
    method: Measured on MISSE 2 flight samples and listed in NASA TM-2008-215490, Table I
    status: flight
    source: nasa-tm-2008-215490
    where: Table I (MISSE 2 PEACE polymers erosion yield data), row Cellulose acetate, CA; fluence in section 2 text
  - benchmark: atomic_oxygen_erosion_yield
    label: Atomic oxygen erosion yield, cellulose acetate (predicted)
    value: 5.06e-24
    unit: cm3/atom
    scope: material
    conditions:
      basis: NASA predictive tool, NASA TM-2008-215490
    method: Predicted by the NASA predictive tool and listed next to the MISSE 2 measured value
    status: prediction
    source: nasa-tm-2008-215490
    where: Table VII (comparison of predicted and actual measured atomic oxygen erosion yields), row Cellulose acetate, CA
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, Eastman CA-398-3
    value: 180
    unit: °C
    scope: material
    conditions:
      grade: Eastman Cellulose Acetate CA-398-3
      method_as_printed: Glass Transition Temperature (Tg)
    method: Typical value printed on the manufacturer product data sheet; the sheet notes typical values for average lots
    status: ground
    source: eastman-tds-ca398-3
    where: Typical Properties table, page 2, Glass Transition Temperature (Tg) row
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, Eastman CA-398-30
    value: 189
    unit: °C
    scope: material
    conditions:
      grade: Eastman Cellulose Acetate CA-398-30
      method_as_printed: Glass Transition Temperature (Tg)
    method: Typical value printed on the manufacturer product data sheet
    status: ground
    source: eastman-tds-ca398-30
    where: Typical Properties table, Glass Transition Temperature (Tg) row
  - benchmark: density
    label: Specific gravity, Eastman CA-398-3
    value: 1.31
    unit: g/cm3
    scope: material
    conditions:
      grade: Eastman Cellulose Acetate CA-398-3
      basis: specific gravity as printed (Wt/Vol 1.31 kg/L)
    method: Typical value printed on the manufacturer product data sheet
    status: ground
    source: eastman-tds-ca398-3
    where: Typical Properties table, Specific Gravity row
  - benchmark: density
    label: Relative density, Eastman CA-398-10
    value: 1.31
    value_high: 1.32
    unit: g/cm3
    scope: material
    conditions:
      grade: Eastman Cellulose Acetate CA-398-10
      basis: relative density as printed in the safety data sheet
    method: Printed in the manufacturer safety data sheet, physical and chemical properties block
    status: ground
    source: eastman-sds-ca398-10
    where: Section 9, Relative density row
  - benchmark: refractive_index
    label: Refractive index, Eastman CA-398-3
    value: 1.475
    unit: '-'
    scope: material
    conditions:
      grade: Eastman Cellulose Acetate CA-398-3
    method: Typical value printed on the manufacturer product data sheet; no temperature or wavelength printed
    status: ground
    source: eastman-tds-ca398-3
    where: Typical Properties table, Refractive Index row
  - benchmark: dielectric_strength
    label: Dielectric strength, Eastman CA-398-3
    value: 669
    unit: kv/cm
    scope: material
    conditions:
      grade: Eastman Cellulose Acetate CA-398-3
      minimum_as_printed: 1.7 kv/mil
    method: Typical value printed on the manufacturer product data sheet; no test standard printed
    status: ground
    source: eastman-tds-ca398-3
    where: Typical Properties table, page 2, Dielectric Strength row
  - benchmark: melting_point
    label: Melting point, Eastman CA-398-3 (data sheet)
    value: 230
    value_high: 250
    unit: °C
    scope: material
    conditions:
      grade: Eastman Cellulose Acetate CA-398-3
    method: Typical value printed on the manufacturer product data sheet; the 2016 to 2018 SDS for the same grade prints melting point as not determined
    status: ground
    source: eastman-tds-ca398-3
    where: Typical Properties table, Melting Point row
  - benchmark: decomposition_temperature
    label: Decomposition temperature, Eastman CA-398-3
    value: 304
    unit: °C
    scope: material
    conditions:
      grade: Eastman Cellulose Acetate CA-398-3
      printed_as: 579 °F / 304 °C
    method: Printed in the manufacturer safety data sheet, physical and chemical properties section; no method printed for the temperature
    status: ground
    source: eastman-sds-ca398-3
    where: Physical and chemical properties section, Decomposition temperature row
  - benchmark: decomposition_energy
    label: Decomposition energy, Eastman CA-398-3
    value: 123
    unit: J/g
    scope: material
    conditions:
      grade: Eastman Cellulose Acetate CA-398-3
    method: DSC, as printed in the manufacturer safety data sheet, section 9
    status: ground
    source: eastman-sds-ca398-3
    where: Section 9, Decomposition energy (mass) row
  - benchmark: acetyl_content
    label: Acetyl content, Eastman CA-398-3
    value: 39.8
    unit: wt %
    scope: material
    conditions:
      grade: Eastman Cellulose Acetate CA-398-3
    method: Typical value printed on the manufacturer product data sheet
    status: ground
    source: eastman-tds-ca398-3
    where: Typical Properties table, Acetyl Content row
  - benchmark: hydroxyl_content
    label: Hydroxyl content, Eastman CA-398-3
    value: 3.5
    unit: wt %
    scope: material
    conditions:
      grade: Eastman Cellulose Acetate CA-398-3
    method: Typical value printed on the manufacturer product data sheet
    status: ground
    source: eastman-tds-ca398-3
    where: Typical Properties table, Hydroxyl Content row
corrosion:
  - environment: Low Earth orbit, atomic oxygen
    headline: CA erodes at 5.05e-24 cm3/atom on MISSE 2, about 1.9 times the PP value on the same tray.
    effect: NASA lists the flight erosion yield of cellulose acetate as 5.05e-24 cm3/atom after an 8.43e21 atoms/cm2 fluence over four years, against 2.68e-24 cm3/atom for polypropylene on the same experiment.
    conditions:
      basis: flight samples on the ISS, MISSE 2 PEACE tray, 4 year exposure
      reference: NASA TM-2008-215490, Table I
    source: nasa-tm-2008-215490
    where: Table I, row Cellulose acetate, CA
    rating: unknown
  - environment: Ultraviolet light, accelerated weathering
    headline: The 2023 weathering study found that cellulose acetate is less UV stable than PLA, and that UV light changes its colour.
    effect: Mušič et al. 2023 weathered cigarette-filter CA with a xenon arc lamp and report that PLA was more stable than CA under UV light, with colour change used as the measure. The paper gives no retention figure for CA tensile strength or elongation.
    conditions:
      basis: xenon arc lamp, ground microplastic powder from used cigarette filters, not a service test
      reference: Mušič et al. 2023, Abstract and Section 2.2
    source: mdpi-cigarette-ca-2023
    where: Abstract, final sentence; Section 2.2
    rating: unknown
  - environment: Ultraviolet light below 280 nm
    headline: Photodegradation is fastest at 280 nm or shorter and is enhanced by TiO2 pigment.
    effect: Wikipedia states that photodegradation of cellulose acetate is optimal with 280 nm or shorter UV irradiation and is enhanced by TiO2 pigment, and that CA cigarette filters take years to break down in the open.
    conditions:
      basis: general statement, no test condition given in the source
    source: wikipedia-cellulose-acetate
    where: Disposal and degradation section
    rating: unknown
  - environment: Heat or moisture on film
    headline: Acid in cellulose acetate film releases acetic acid when heat or moisture act on it, a process called vinegar syndrome.
    effect: Wikipedia states that, when exposed to heat or moisture, acids in the film base begin to deteriorate the film, releasing acetic acid with a vinegary smell. The page gives no temperature or humidity threshold.
    conditions:
      basis: general statement about cellulose acetate film stock, no test condition given
    source: wikipedia-cellulose-acetate
    where: Film section
    rating: unknown
  - environment: Strong alkali and strong oxidizing agents
    headline: Strong alkaline solutions and strong oxidizers weaken CA, and the Eastman SDS lists strong oxidizing agents as incompatible.
    effect: Wikipedia states that cellulose acetate is easily weakened by strong alkaline solutions and strong oxidizing agents. The Eastman SDS lists strong oxidizing agents as incompatible materials and carbon monoxide and carbon dioxide as hazardous decomposition products.
    conditions:
      basis: general statement from Wikipedia; SDS incompatibility list for the CA-398-3 grade
    source: eastman-sds-ca398-3
    where: Section 10, Incompatible materials and Hazardous decomposition products rows
    rating: unknown
risks:
  hazards:
    - text: GHS classification is Combustible dust, with the signal word Warning and the statement May form combustible dust concentrations in air. Flash point is printed as not applicable, combustible solid.
      ghs: []
      source: eastman-sds-ca398-3
      where: Sections 2 and 9
    - text: The dust explosion class is printed as St 2, strong explosion. The SDS says fine dust dispersed in air with an ignition source is a potential dust explosion hazard.
      ghs: []
      source: eastman-sds-ca398-3
      where: Fire-fighting measures section and physical and chemical properties section (dust explosion class row)
    - text: 'Carcinogenicity: no ingredient at 0.1 % or more is listed by IARC, OSHA or NTP for the CA-398-10 grade.'
      ghs: []
      source: eastman-sds-ca398-10
      where: Regulatory information section (IARC, OSHA and NTP rows)
  failure_risks:
    - mode: Atomic oxygen erosion in low Earth orbit
      trigger: Exposure of a cellulose acetate part to atomic oxygen in low Earth orbit, as on the MISSE 2 flight
      consequence: Surface erosion at a yield of 5.05e-24 cm3/atom as measured on MISSE 2, with 5.06e-24 cm3/atom predicted by NASA.
      severity: moderate
      source: nasa-tm-2008-215490
      where: Table I and Table VII
    - mode: Acid release under heat or moisture
      trigger: Heat or moisture acting on cellulose acetate film base
      consequence: The film deteriorates and releases acetic acid, with a vinegar smell (vinegar syndrome). Wikipedia notes this was the failure mode of historic acetate film stock.
      severity: moderate
      source: wikipedia-cellulose-acetate
      where: Film section
  side_effects: []
  handling:
    - text: Minimise dust generation and accumulation, and keep ignition sources away from dust clouds, since the SDS classes the dust as St 2.
      source: eastman-sds-ca398-3
    - text: The grade is a solid powder or flake with a negligible water solubility; the SDS prints no hazard classification beyond combustible dust.
      source: eastman-sds-ca398-3
    - text: The SDS documents read here are dated 2016 to 2018, so check the current supplier SDS for the grade before handling.
      source: eastman-sds-ca398-3
  mitigations: []
uses:
  - application: optics-and-cameras
    device: Photographic and motion-picture film base
    example: Cellulose acetate film replaced cellulose nitrate film for photographic use in the 1950s, being far less flammable and cheaper to produce, according to Wikipedia.
    source: wikipedia-cellulose-acetate
    where: Film section
  - application: electronics-and-chips
    device: Polymer sample on a space flight experiment
    example: Cellulose acetate on the MISSE 2 PEACE tray, flown on the ISS in low Earth orbit, with its erosion yield listed in NASA TM-2008-215490.
    source: nasa-tm-2008-215490
    where: Table I
supply:
  - subject: Cellulose acetate (global output)
    demand: The Wikipedia article gives over 800,000 tonnes per year of CA materials in 2008. The article cites no primary source for this figure.
    routes: Purified cellulose from wood pulp or cotton linters is acetylated with acetic acid and acetic anhydride, then partially hydrolysed to the secondary acetate.
    producers: []
    critical_lists: []
    substitutes: []
    source: wikipedia-cellulose-acetate
    where: Production section and Disposal and degradation section
    abundance: 'Producers named in the article: Celanese and Eastman Chemical Company in the US, and DP Acetate in the EU for filament yarn. No country shares were read.'
  - subject: Cellulose feedstock
    demand: Not read in this run.
    routes: Wood pulp or cotton linters, a renewable resource according to Wikipedia.
    producers: []
    critical_lists: []
    substitutes: []
    source: wikipedia-cellulose-acetate
    where: Characteristics list and Production section
documents:
  - title: Eastman Cellulose Acetate (CA-398-3), product data sheet
    type: datasheet
    url: https://www.chempoint.com/products/download?grade=3672&doctype=tds&documentid=0103000199393021445228&language=English
    year: 2008
  - title: Eastman Cellulose Acetate (CA-398-30), product data sheet
    type: datasheet
    url: https://www.chempoint.com/products/download?grade=3673&type=tds
  - title: Eastman Cellulose Acetate (CA-398-3), safety data sheet, version 2.1
    type: sds
    url: https://www.chempoint.com/products/download?grade=3672&type=msds
    year: 2018
  - title: Eastman Cellulose Acetate (CA-398-10), safety data sheet, version 225.1
    type: sds
    url: https://www.chempoint.com/products/download?doctype=sds&grade=3671
  - title: Banks, de Groh and Backus, 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: Mušič, Jemec Kokalj and Sever Škapin, Influence of Weathering on the Degradation of Cellulose Acetate Microplastics Obtained from Used Cigarette Butts, Polymers 15(12), 2751
    type: paper
    url: https://www.mdpi.com/2073-4360/15/12/2751
    year: 2023
  - title: NIST Atomic Weights and Isotopic Compositions for All Elements (H, C and O rows)
    type: database
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=O&all=all&ascii=html
sources:
  nasa-tm-2008-215490:
    title: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit
    id: NASA/TM-2008-215490 (Banks, de Groh and Backus, 2008), NTRS 20090011780
    url: https://ntrs.nasa.gov/citations/20090011780
    year: 2008
    kind: report
    license: NASA public document
  eastman-tds-ca398-3:
    title: Eastman Cellulose Acetate (CA-398-3), product data sheet
    id: Typical Properties table, printed 6/19/2008 from eastman.com
    url: https://www.chempoint.com/products/download?grade=3672&doctype=tds&documentid=0103000199393021445228&language=English
    year: 2008
    kind: datasheet
    license: manufacturer data sheet, linked not reproduced
  eastman-tds-ca398-30:
    title: Eastman Cellulose Acetate (CA-398-30), product data sheet
    id: Typical Properties table
    url: https://www.chempoint.com/products/download?grade=3673&type=tds
    kind: datasheet
    license: manufacturer data sheet, linked not reproduced
  eastman-sds-ca398-3:
    title: Eastman Cellulose Acetate (CA-398-3), safety data sheet
    id: SDS version 2.1, revision 06/14/2018, SDS number 150000001217
    url: https://www.chempoint.com/products/download?grade=3672&type=msds
    year: 2018
    kind: datasheet
    license: supplier SDS, linked not reproduced
  eastman-sds-ca398-10:
    title: Eastman Cellulose Acetate (CA-398-10), safety data sheet
    id: SDS version 225.1
    url: https://www.chempoint.com/products/download?doctype=sds&grade=3671
    kind: datasheet
    license: supplier SDS, linked not reproduced
  mdpi-cigarette-ca-2023:
    title: Influence of Weathering on the Degradation of Cellulose Acetate Microplastics Obtained from Used Cigarette Butts
    id: Mušič, Jemec Kokalj and Sever Škapin, Polymers 15(12), 2751, doi 10.3390/polym15122751
    url: https://www.mdpi.com/2073-4360/15/12/2751
    year: 2023
    kind: paper
    license: open access article, linked not reproduced
  wikipedia-cellulose-acetate:
    title: Cellulose acetate, Wikipedia
    id: Cellulose acetate article, Film, Production, Disposal and degradation sections
    url: https://en.wikipedia.org/wiki/Cellulose_acetate
    kind: web
    license: CC BY-SA 4.0, linked not reproduced
  nist-atomic-weights:
    title: NIST Atomic Weights and Isotopic Compositions for All Elements (H, C and O rows)
    id: 'NIST standard atomic weight table: C [12.0096, 12.0116]; H [1.007 84, 1.008 11]; O [15.999 03, 15.999 77]'
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=O&all=all&ascii=html
    kind: database
    license: US government data
gaps:
  - Tensile strength, elongation and modulus of Eastman CA-398-3 or CA-398-30 were not printed on the sources read. The datasheets say the full mechanical data sit behind an account.
  - Heat deflection temperature, Vicat softening temperature and maximum service temperature for CA were not read on a fetched page in this run.
  - Melting point is printed as 230 to 250 °C on the Eastman data sheet but as not determined in the SDSs read; the conflict is recorded, not resolved.
  - UV ageing numbers for CA (retention of tensile strength or elongation after a dose) were not read; the 2023 paper reports colour change and particle size only.
  - Outgassing, total mass loss, radiation and vacuum data for cellulose acetate in space were not read in this run, beyond the erosion yield.
  - Chemical resistance to solvents, water absorption and moisture uptake values were not read on a fetched page in this run.
  - Supply by country share and current producer tonnages were not found on a primary source; the 800,000 tonnes figure is a 2008 value cited without a source.
  - Critical-mineral status is not applicable to a cellulose ester, so no USGS or EU list entry was added.
  - Decomposition temperature, decomposition energy, acetyl content and hydroxyl content are not in the canonical property file, so their snake_case names are used as printed; the canonical list may need them.
  - The PubChem record for cellulose acetate returned no data in this run, so no PubChem GHS entry is recorded.
  - The formula printed by NASA (C12H16O8) is a triacetate-type repeat unit, while Wikipedia calls the common form diacetate; the grade data (39.8 wt % acetyl) sit between the two.
license: CC-BY-4.0
updated: '2026-10-20'
review:
  status: draft
  method: assistant
  checked_values: 14
  unreachable: 2
  caveats: 4
  note: 'Values were read by an AI assistant on 2026-10-20 from the pages named in each entry. NASA Table I, II, IV and VII were read from the text of the NTRS PDF. Eastman datasheets and SDSs were read from the ChemPoint PDF downloads. Unreachable: the PubChem cellulose acetate record (no data returned) and the ULprospector CA-398-3 page (blocked by a bot check). Caveats: the Eastman CA-398-3 melting point conflicts with its SDS; the NASA formula is a triacetate-type repeat unit; the erosion yield is a single flight sample; the 2023 UV study is on cigarette-filter powder, not film.'
story:
  recipe:
    line: Cellulose acetate is made by acetylating cellulose, a glucose polymer with three hydroxyls per anhydroglucose unit, with acetic acid and acetic anhydride under a sulfuric acid catalyst, then partially hydrolysing the triacetate to a lower acetyl content. The repeat unit printed by NASA is C12H16O8.
    parts:
      - name: Carbon
        symbol: C
        role: Twelve carbons per repeat unit, in the glucose ring and the acetyl groups.
        share_note: atomic_weight [12.0096, 12.0116]
      - name: Hydrogen
        symbol: H
        role: Sixteen hydrogens per repeat unit, on the ring and in the acetyl methyl groups.
        share_note: atomic_weight [1.007 84, 1.008 11]
      - name: Oxygen
        symbol: O
        role: Eight oxygens per repeat unit, in the ring and the ester groups.
        share_note: atomic_weight [15.999 03, 15.999 77]
  risk_groups:
    - title: For people
      lead: The SDS pages read here classify cellulose acetate by its dust, not by a toxic hazard.
      level: 1
      verdict: Combustible dust, no toxic classification
      points:
        - label: Classification
          line: The Eastman SDSs print the GHS classification as combustible dust with the warning Warning, and no acute toxicity classification is printed.
        - label: Dust
          line: The dust explosion class is printed as St 2, strong explosion, so fine dust needs the same care as other combustible dusts.
    - title: If it fails
      lead: The failure routes in these sources are erosion in orbit and acid release from film under heat or moisture.
      points:
        - label: Atomic oxygen
          line: On MISSE 2 the erosion yield was 5.05e-24 cm3/atom, against 5.06e-24 cm3/atom predicted by NASA.
        - label: Heat and moisture
          line: Wikipedia describes acetic acid release from film exposed to heat or moisture, which is the vinegar syndrome of historic film stock.
  why: Cellulose acetate is a stiff, clear cellulose ester with a glass transition of 180 °C in the Eastman CA-398-3 grade and a density of 1.31 g/cm3 on the data sheet. The NASA report gives a density of 1.2911 g/cm3 for the MISSE 2 sample. Its flight erosion yield of 5.05e-24 cm3/atom is the reference value for the ester in low Earth orbit.
  uses:
    - where: Use
      line: Photographic and motion-picture film base, which replaced nitrate film in the 1950s (Wikipedia).
    - where: Use
      line: Eyeglass frames, fibres for fabrics and cigarette filters (Wikipedia).
    - where: Use
      line: Coatings and plastics with plasticisers, as the Eastman data sheet lists for CA-398-3 (coatings for glass and paper, food-contact films, electrical uses).
  can_do:
    - label: Stiff and clear at room temperature
      value: 180 °C glass transition
      benchmark: glass_transition_temperature
      line: The Eastman CA-398-3 data sheet prints a glass transition of 180 °C and a refractive index of 1.475.
    - label: Insulate
      value: 669 kv/cm dielectric strength
      benchmark: dielectric_strength
      line: The same data sheet prints a dielectric strength of 669 kv/cm (1.7 kv/mil), as a typical value without a test standard.
    - label: Survive in orbit
      value: 5.05e-24 cm3/atom
      benchmark: atomic_oxygen_erosion_yield
      line: NASA lists a MISSE 2 erosion yield for cellulose acetate of 5.05e-24 cm3/atom, and predicts 5.06e-24 cm3/atom in Table VII.
  compare: The grades and test methods differ between the sources, so the rows show each property as its own example, not a ranking. The Eastman CA-398-3 glass transition of 180 °C and CA-398-30 value of 189 °C are two grades of the same ester.
  compare_rows:
    - scope: material
      label: Density
      benchmark: density
    - scope: material
      label: Erosion yield
      benchmark: atomic_oxygen_erosion_yield
    - scope: material
      label: Glass transition
      benchmark: glass_transition_temperature
  handling:
    - Specify the grade, since acetyl content, viscosity and glass transition change with the grade (CA-398-3 and CA-398-30 differ).
    - Control dust in the work area and keep ignition sources away from dust clouds, as the SDS directs.
    - Keep the material away from strong oxidisers and strong alkaline solutions, as the SDS and Wikipedia state.
  good_for:
    - 'Clear film base and coating grades: a glass transition of 180 °C and a refractive index of 1.475 for the Eastman CA-398-3 grade.'
    - 'Known atomic oxygen behaviour: 5.05e-24 cm3/atom on MISSE 2 in low Earth orbit, measured on a flight sample.'
    - Dielectric use at a printed 669 kv/cm (typical), for the same grade.
  watch_out:
    - 'Heat and moisture: the SDS prints a decomposition temperature of 304 °C, and sources say acetic acid is released from film under heat or moisture.'
    - 'Atomic oxygen: the flight erosion yield of 5.05e-24 cm3/atom is about 1.9 times the 2.68e-24 cm3/atom measured for polypropylene on the same tray.'
    - 'Melting point: the Eastman data sheet prints 230 to 250 °C, while the SDS prints not determined, so do not treat the melting range as settled.'
    - No tensile, outgassing or UV retention data for CA were found in this run.
  verdict: Cellulose acetate is a stiff cellulose ester with a glass transition of 180 °C in the Eastman CA-398-3 grade and a MISSE 2 erosion yield of 5.05e-24 cm3/atom in low Earth orbit. It is a combustible dust, and it degrades under heat, moisture and UV. This profile has no sourced tensile, outgassing or UV retention values.