spore: profile
id: adc-cr-39
spore_version: 0.2
family: engineering-polymers
name: Poly(allyl diglycol carbonate), ADC (CR-39)
abbreviation: ADC (CR-39)
role: clear, light thermoset used for eyeglass lenses and as a solid-state nuclear track detector
category: polymers
type: polycarbonates
summary: Poly(allyl diglycol carbonate), sold as CR-39, is a clear, rigid thermoset made by polymerising the liquid monomer allyl diglycol carbonate (C12H18O7). The cured plastic has a refractive index of 1.498, a specific gravity of 1.32 and transmits 91 % of light in a comparative test. It is used for eyeglass lenses and as a track detector for alpha particles and neutrons. On MISSE 2 it flew on the ISS PEACE tray and its atomic-oxygen erosion yield was greater than 6.80e-24 cm3/atom.
best_for: 'Light, clear optical parts and track detectors: 1.498 refractive index and about half the weight of glass (Wikipedia)'
weakest_at: Atomic oxygen in low Earth orbit (erosion yield above 6.80e-24 cm3/atom on MISSE 2) and UV, which changes its optical absorption and etch behaviour
identity:
  formula: Poly(allyl diglycol carbonate), a crosslinked thermoset of the monomer diethylene glycol bis(allyl carbonate), C12H18O7 (monomer)
  cas: 25656-90-0 for the polymer (Wikipedia infobox); 142-22-3 for the monomer (Wikipedia infobox)
  source: nasa-tm2008
  where: Table IV, row ADC (CR-39), repeat unit C12H18O7 and molar mass 274.2700
tags:
  environments:
    - low-earth-orbit
  stresses:
    - atomic-oxygen
    - uv
  applications:
    - optics-and-cameras
    - radiation-shielding
properties:
  - benchmark: density
    label: Density, cured polymer (MISSE 2 study table)
    value: 1.3173
    unit: g/cm3
    scope: material
    conditions:
      state: cured polymer
      temperature: not printed
    method: Value printed in the NASA erosion study, Table II, column g/cm3
    status: ground
    source: nasa-tm2008
    where: Table II, row Allyl diglycol carbonate, ADC (CR-39)
  - benchmark: density
    label: Specific gravity, CR-39 comparative example
    value: 1.32
    unit: specific gravity (unitless)
    scope: material
    conditions:
      state: cured polymer
      temperature: not printed
    method: Printed in a patent comparative example table (specific gravity, no unit printed)
    status: ground
    source: patent-us5350822
    where: Table 1 and Table 3, CR-39 column (labelled Comparative Example 2)
  - benchmark: density
    label: Density, liquid monomer ADC
    value: 1.143
    unit: g/cm3
    scope: material
    conditions:
      state: liquid monomer, allyl diglycol carbonate
      temperature: not printed
    method: Value printed in the Wikipedia infobox for diallyl diglycol carbonate
    status: ground
    source: wikipedia-adc
    where: Infobox, Diallyl diglycol carbonate (ADC monomer)
  - benchmark: refractive_index
    label: Refractive index, cured CR-39
    value: 1.498
    unit: unitless
    scope: material
    conditions:
      wavelength: not printed
      state: cured polymer
    method: Printed as n_D in a patent comparative example and in Wikipedia
    status: ground
    source: patent-us5350822
    where: Table 1, CR-39 column; also Wikipedia CR-39 lead section
  - benchmark: refractive_index
    label: Refractive index, monomer ADC
    value: 1.45
    unit: unitless
    scope: material
    conditions:
      state: liquid monomer
      temperature: not printed
    method: Printed as nD in the Wikipedia infobox for the monomer
    status: ground
    source: wikipedia-adc
    where: Infobox, Diallyl diglycol carbonate (ADC monomer)
  - benchmark: light_transmittance
    label: Light transmittance, CR-39 comparative example
    value: 91
    unit: '%'
    scope: material
    conditions:
      thickness: not printed
      state: cured polymer
    method: Printed as "Transparence" in a patent comparative example table
    status: ground
    source: patent-us5350822
    where: Table 1, CR-39 column (labelled Comparative Example 2)
  - benchmark: light_transmittance
    label: Light transmittance, commercial ADC plates
    value: 92
    unit: '%'
    scope: material
    conditions:
      thickness: 2 mm plates
      state: commercial cured ADC
    method: Printed in a patent table for commercial ADC plates
    status: ground
    source: patent-us6417273
    where: Table 4, Comparative Example 1 (ADC, commercial 2 mm plates), light transmittance row
  - benchmark: glass_transition_temperature
    label: Heat resistance, equal to the glass transition per the source
    value: 91
    unit: °C
    scope: material
    conditions:
      basis: temperature of maximum tan delta, which the source calls the glass transition
      sample: commercial ADC 2 mm plate
    method: Printed as heat resistance in a patent table; the text defines it as the temperature of maximum tan delta, which the patent calls Tg
    status: ground
    source: patent-us6417273
    where: Table 4, Comparative Example 1, heat resistance row
  - benchmark: max_service_temp
    label: Continuous use temperature
    value: 100
    unit: °C
    scope: material
    conditions:
      duration: continuous
      basis: optical use in eyeglasses
    method: Printed in the Wikipedia article for CR-39 (citation needed on the short-term figure)
    status: ground
    source: wikipedia-cr39
    where: Applications, Optics section
  - benchmark: cte
    label: Linear expansion coefficient, CR-39 comparative example
    value: 117
    unit: µm/m/°C
    scope: material
    conditions:
      temperature_range: not printed
      state: cured polymer
    method: Printed in a patent comparative example table as linear expansion coefficient
    status: ground
    source: patent-us5350822
    where: Table 3, CR-39 row (Comparative Example 2)
  - benchmark: moisture_absorption
    label: Water absorption, CR-39 comparative example
    value: 0.2
    unit: '%'
    scope: material
    conditions:
      duration: not printed
      state: cured polymer
    method: Printed as water absorption rate in a patent comparative example table
    status: ground
    source: patent-us5350822
    where: Table 1, CR-39 column (Comparative Example 2)
  - benchmark: atomic_oxygen_erosion_yield
    label: Atomic oxygen erosion yield, MISSE 2 (lower bound)
    value: 6.8e-24
    unit: cm3/atom
    bound: lower
    scope: material
    conditions:
      bound: lower bound; the printed value is greater than 6.80e-24 because the sample eroded through
      exposure: MISSE 2 PEACE tray on the ISS
    method: Flight measurement reported in the NASA predictive-tool report
    status: flight
    source: nasa-tm2008
    where: Table I, row Allyl diglycol carbonate, ADC (CR-39), MISSE 2 erosion yield column
  - benchmark: atomic_oxygen_erosion_yield
    label: Atomic oxygen erosion yield, predicted
    value: 6.3e-24
    unit: cm3/atom
    scope: material
    conditions:
      exposure: low Earth orbit atomic oxygen (predictive tool)
    method: Predicted value from the NASA predictive tool, compared with MISSE 2 in Table VII
    status: calculated
    source: nasa-tm2008
    where: Table VII, row Allyl diglycol carbonate, predicted erosion yield column
  - benchmark: molar_mass
    label: Molar mass, repeat unit C12H18O7
    value: 274.27
    unit: g/mol
    scope: material
    conditions:
      basis: repeat unit as tabulated by NASA
    method: Printed in the NASA erosion study Table IV
    status: ground
    source: nasa-tm2008
    where: Table IV, row Allyl diglycol carbonate, ADC (CR-39), molar mass column
  - benchmark: melting_point
    label: Melting point, monomer ADC
    value: -4
    unit: °C
    scope: material
    conditions:
      state: liquid monomer
    method: Printed in the Wikipedia infobox for the monomer
    status: ground
    source: wikipedia-adc
    where: Infobox, Diallyl diglycol carbonate (ADC monomer)
  - benchmark: optical_absorption_coefficient
    label: Optical absorption coefficient, UV-C band (215-242 nm)
    value: 54
    unit: cm-1
    scope: material
    conditions:
      wavelength: 215-242 nm
      exposure: UV-exposed CR-39
    method: Maximum value computed from UV-Vis spectra in the cited study
    status: ground
    source: inoe-uv-padc
    where: Section 2 (Eq. 5 discussion), sentence on maximum optical absorption coefficient
  - benchmark: optical_absorption_coefficient
    label: Optical absorption coefficient, UV-A band (315-400 nm)
    value: 1
    unit: cm-1
    scope: material
    conditions:
      wavelength: 315-400 nm
      exposure: UV-exposed CR-39
    method: Value computed from UV-Vis spectra in the cited study
    status: ground
    source: inoe-uv-padc
    where: Section 2 (Eq. 5 discussion), same sentence as the 215-242 nm value
  - benchmark: energy_resolution
    label: Energy resolution, 2.9 MeV protons
    value: 3
    unit: '%'
    scope: material
    conditions:
      particle: protons, 2.9 MeV
      detector: 1 mm slotted CR-39 plate
    method: Printed in the track-detector study, energy resolution section
    status: ground
    source: pmc-tasl-cr39
    where: Energy resolution section, sentence on 2.9 MeV and 3.15 MeV protons
  - benchmark: polymerization_time
    label: Polymerization time, CR-39 comparative example
    value: 18
    unit: hours
    scope: material
    conditions:
      temperature: not printed
      initiator: not printed
    method: Printed in a patent comparative example table
    status: ground
    source: patent-us5350822
    where: Table 1, CR-39 column, polymerization time row
corrosion:
  - environment: UV light (wavelength 254 nm and 365 nm, laboratory lamp)
    headline: UV at 254 nm changes CR-39 optical absorption and its etch rate; UV at 365 nm did not change them in the cited study.
    effect: At 254 nm the UV-Vis spectrum shows blue and red shifts and the band gap decreases with exposure time. At 365 nm there was no significant change in bulk etch rate or UV-Vis spectrum, even after 80 hours. The study also found that the bulk etch rate is modified by a factor that depends on the UV dose.
    rating: moderate
    conditions:
      exposure: UV lamp 254 nm and 365 nm, 4 watt, samples 4 cm2
      etchant: 6.25N NaOH at 70 °C
    source: inoe-uv-padc
    where: Abstract; Section 3.1 (effect of UV on the bulk etch rate)
  - environment: Atomic oxygen in low Earth orbit (MISSE 2, ISS, 3.95 years)
    headline: The erosion yield is above 6.80e-24 cm3/atom, so the sample eroded through before the end of the exposure.
    effect: The lower-bound erosion yield exceeds the predicted value of 6.30e-24 cm3/atom, so the true yield is at least as high as the measured lower bound.
    rating: severe
    conditions:
      exposure: MISSE 2 PEACE tray, ISS, outside the Quest airlock, 2001 to 2005
    source: nasa-tm2008
    where: Table I and Table VII
risks:
  hazards:
    - text: 'Diallyl diglycol carbonate, the liquid monomer (CAS 142-22-3): GHS hazard statements H302, H315 and H410 with signal word Warning, pictograms GHS07 and GHS09.'
      ghs:
        - H302
        - H315
        - H410
      source: wikipedia-adc
      where: Infobox, Hazards (GHS)
    - text: No GHS classification for the cured polymer was read in this run. The hazard statements above describe the uncured monomer.
      ghs: []
      source: wikipedia-cr39
      where: Infobox and lead section (no hazard data printed for the polymer)
  failure_risks:
    - mode: UV-induced change in optical absorption and etch behaviour
      trigger: Exposure to short-wavelength UV (254 nm in the cited study)
      consequence: Optical absorption rises and etch behaviour changes, so calibration of the track detector can drift. Changes at 365 nm were not measurable in the study.
      severity: moderate
      source: inoe-uv-padc
      where: Abstract; Section 3.1
    - mode: Atomic oxygen erosion in low Earth orbit
      trigger: Long exposure to atomic oxygen on the ISS, MISSE 2 PEACE tray
      consequence: The sample eroded through in the MISSE 2 flight, so its erosion yield is only a lower bound.
      severity: critical
      source: nasa-tm2008
      where: Table I
  handling:
    - text: Keep continuous use at or below 100 °C, since the Wikipedia article gives 130 °C only for up to one hour and marks it as citation needed.
      source: wikipedia-cr39
      where: Applications, Optics section
    - text: Handle the liquid monomer with the GHS precautions printed for it (H302, H315, H410); the cured polymer was not classified in the pages read.
      source: wikipedia-adc
      where: Infobox, Hazards (GHS)
uses:
  - application: optics-and-cameras
    device: Eyeglass and sunglass lenses
    example: CR-39 lenses weigh about half as much as glass, and the first CR-39 lenses were made in 1947 by the Armorlite Lens Company.
    source: wikipedia-cr39
    where: Applications, Optics section, and History
  - application: radiation-shielding
    device: Solid-state nuclear track detector (dosimetry, not shielding)
    example: CR-39 records tracks from alpha particles, neutrons, protons and radon, and is etched in concentrated sodium hydroxide to reveal them.
    source: pmc-tasl-cr39
    where: Introduction and Experimental set-up, sections 1 and 2
  - application: structures
    device: Space exposure test sample (MISSE 2, flight)
    example: ADC (CR-39) flew on the MISSE 2 PEACE tray on the ISS from 2001 to 2005, and its erosion yield is recorded in Table I.
    source: nasa-tm2008
    where: Table I and Section 2.1 (exposure)
supply:
  - subject: Diethylene glycol bis(allyl carbonate) monomer (ADC)
    demand: Not read in this run. The monomer is used for cast optical lenses and track detectors (Wikipedia).
    producers:
      - name: PPG Industries
        note: Named as trademark owner of CR-39 on the Wikipedia page (no volume or share read)
        country: United States
    critical_lists: []
    substitutes: []
    source: wikipedia-cr39
    where: History and trademark sections
  - subject: CR-39 track detectors (sold to researchers)
    demand: Track Analysis Systems Ltd (UK) has served researchers in over 80 countries since 2013 (Wikipedia). No volume was read.
    producers:
      - name: Track Analysis Systems Ltd
        note: Radiation track detector supplier, UK (Wikipedia, radiation detection section)
        country: United Kingdom
      - name: BlankSlate Innovation
        note: Custom CR-39 and automated analysis services, US (Wikipedia)
        country: United States
      - name: Nagase Landauer
        note: CR-39 for personal radiation dosimetry, Japan (Wikipedia)
        country: Japan
    critical_lists: []
    substitutes: []
    source: wikipedia-adc
    where: Suppliers (radiation detection section)
documents:
  - title: 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: US patent 5350822, High refractive index plastic lens composition (Comparative Example 2 for CR-39)
    type: paper
    url: https://patents.google.com/patent/US5350822
    year: 1994
  - title: US patent 6417273, Monomer composition for optical plastic material (Comparative Example 1, commercial ADC)
    type: paper
    url: https://patents.google.com/patent/US6417273B1/en
    year: 2002
  - title: Track Analysis Systems CR-39 detector study, PMC open-access article
    type: paper
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC5438376/
    year: 2017
  - title: UV-Vis spectroscopic and chemical etching studies of CR-39 (PADC) exposed to ultraviolet radiation, Optoelectronics and Advanced Materials
    type: paper
    url: https://oam-rc.inoe.ro/articles/uv-vis-spectroscopic-and-chemical-etching-studies-of-cr-39-padc-exposed-to-ultraviolet-radiation/fulltext
    year: 2011
gaps:
  - No glass transition temperature from differential scanning calorimetry was found for the cured polymer. The only Tg value is the heat-resistance figure from a patent table (91 °C), which the patent identifies as the temperature of maximum tan delta.
  - No outgassing data (total mass loss, CVCM) for CR-39 was found in an opened source.
  - No ECHA or PubChem classification was read for the cured polymer. PubChem returned a verification page, so the monomer hazard statements come from Wikipedia only.
  - No current producer volumes or country shares for ADC or CR-39 were read. The supply section names suppliers and trademark owner only.
  - No radiation dose or proton/electron damage value for CR-39 was read in an opened source.
  - The cured polymer's repeat-unit formula was not printed in a fetched page; the formula given is the monomer's, C12H18O7.
  - The NASA erosion yield for MISSE 2 is a lower bound (sample eroded through), so no full-flight yield is recorded.
  - 'Non-canonical property names used: abbe_number, shrinkage (polymerization shrinkage, 13.6 %, is not in this file; see note), atomic_oxygen_erosion_yield, optical_absorption_coefficient, energy_resolution, polymerization_time, molar_mass, light_transmittance.'
  - Polymerisation shrinkage of 13.6 % (patent Table 1) and the Abbe number 58 (patent Table 1, Wikipedia) were read but are not entered as properties because their names are not in the canonical list; they are in the patent source for reference.
  - The Track Analysis Systems TASTRAK datasheet was not reached; its etch rates and thickness options are not recorded.
sources:
  nasa-tm2008:
    title: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit, NASA/TM-2008-215490 (Banks, Backus, de Groh)
    url: https://ntrs.nasa.gov/citations/20090011780
    kind: report
    year: 2008
    license: public domain (NASA)
  wikipedia-cr39:
    title: CR-39, Wikipedia (density, refractive index, Abbe number, heat limits, optics and detector use, history)
    url: https://en.wikipedia.org/wiki/CR-39
    kind: web
    year: 2026
    license: CC BY-SA 4.0
  wikipedia-adc:
    title: Diallyl diglycol carbonate (ADC monomer), Wikipedia (monomer properties, GHS hazards, suppliers)
    url: https://en.wikipedia.org/wiki/Allyl_diglycol_carbonate
    kind: web
    year: 2026
    license: CC BY-SA 4.0
  wikipedia-ssntd:
    title: Solid-state nuclear track detector, Wikipedia (CR-39 as a track detector)
    url: https://en.wikipedia.org/wiki/Solid-state_nuclear_track_detector
    kind: web
    year: 2026
    license: CC BY-SA 4.0
  patent-us5350822:
    title: US5350822, High refractive index plastic lens composition (Table 1 and Table 3, CR-39 comparative example)
    url: https://patents.google.com/patent/US5350822
    kind: paper
    year: 1994
    license: patent document (cited, not reproduced)
  patent-us6417273:
    title: US6417273, Monomer composition for optical plastic material (Table 4, commercial ADC plates)
    url: https://patents.google.com/patent/US6417273B1/en
    kind: paper
    year: 2002
    license: patent document (cited, not reproduced)
  pmc-tasl-cr39:
    title: CR-39 track detector for multi-MeV ion spectroscopy, PMC open-access article
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC5438376/
    kind: paper
    year: 2017
    license: open-access article (cited, not reproduced)
  inoe-uv-padc:
    title: UV-Vis spectroscopic and chemical etching studies of CR-39 (PADC) exposed to ultraviolet radiation, Optoelectronics and Advanced Materials
    url: https://oam-rc.inoe.ro/articles/uv-vis-spectroscopic-and-chemical-etching-studies-of-cr-39-padc-exposed-to-ultraviolet-radiation/fulltext
    kind: paper
    year: 2011
    license: open-access article (cited, not reproduced)
license: CC-BY-4.0
updated: '2026-10-20'
review:
  status: draft
  method: assistant
  checked_values: 19
  unreachable: 2
  caveats: 4
  note: 'Values read by an AI assistant on 2026-10-20 from the pages named in each entry. Unreachable: PubChem (reCAPTCHA page), ECHA (HTTP 403). The US patent 6417273 scanned PDF was image-only; its HTML page was read instead. The NASA erosion value is a lower bound.'
story:
  recipe:
    line: Poly(allyl diglycol carbonate) is made by polymerising the liquid monomer diethylene glycol bis(allyl carbonate), C12H18O7 (NASA Table IV; Wikipedia). The monomer is cured with a peroxide initiator, diisopropyl peroxydicarbonate, over about 18 hours (patent Table 1). The allyl groups crosslink, which makes the polymer a thermoset with no melting point.
    parts:
      - name: Diethylene glycol bis(allyl carbonate), allyl diglycol carbonate
        symbol: ADC
        role: Monomer. Its allyl groups crosslink on polymerisation.
        share_note: Molar mass 274.2700 g/mol (NASA Table IV)
      - name: Diisopropyl peroxydicarbonate
        symbol: IPP
        role: Initiator for the radical cure. Benzoyl peroxide is an alternative that gives a higher yellowness index (Wikipedia).
        share_note: Share not read
  risk_groups:
    - title: For people
      lead: The monomer carries H302, H315 and H410 hazard statements. The cured polymer was not classified in the pages read.
      level: 1
      verdict: Monomer hazardous, polymer not classified
      points:
        - label: Liquid monomer
          line: Diallyl diglycol carbonate has GHS statements H302, H315 and H410 with signal word Warning (Wikipedia).
    - title: If it fails
      lead: UV and atomic oxygen both change the material, and the MISSE 2 sample eroded through.
      points:
        - label: UV at 254 nm
          line: UV at 254 nm raises optical absorption to 54 cm-1 in the 215-242 nm band, while UV-A at 315-400 nm gives only 1 cm-1 (Section 2).
        - label: Atomic oxygen in orbit
          line: The MISSE 2 erosion yield is greater than 6.80e-24 cm3/atom after 3.95 years on the ISS, so the true yield is at least that.
    - title: Handling and storage
      points:
        - label: Keep under the heat limit
          line: Continuous use is up to 100 °C for optics (Wikipedia).
  why: 'CR-39 is a clear, light plastic: its refractive index is 1.498, its specific gravity is 1.32 and it transmits 91 % of light in the patent comparison. Its heat resistance is 91 °C, and it weighs about half as much as glass. It is also a reliable track detector, with energy resolution of 3 % for 2.9 MeV protons.'
  can_do:
    - label: Let light through
      value: 91 % light transmittance
      benchmark: light_transmittance
      line: The CR-39 comparative example in the patent transmits 91 % of light, and a commercial 2 mm ADC plate transmits 92 %.
    - label: Bend light well
      value: 1.498 refractive index
      benchmark: refractive_index
      line: The cured plastic has a refractive index of 1.498, close to the value for crown glass, per Wikipedia.
    - label: Detect particles
      value: 3 % energy resolution for 2.9 MeV protons
      benchmark: energy_resolution
      line: The track-detector study reports 3 % energy resolution for 2.9 MeV protons and 4 % for 3.15 MeV.
    - label: Stay clear in heat
      value: 100 °C continuous use
      benchmark: max_service_temp
      line: CR-39 is rated for continuous use up to 100 °C, and up to one hour at 130 °C per Wikipedia (citation needed).
  uses:
    - where: Eyeglass lenses
      line: CR-39 lenses weigh about half as much as glass, and the first were made in 1947.
    - where: Track detectors
      line: CR-39 records alpha particles, neutrons, protons and radon, and is etched in sodium hydroxide to reveal tracks.
    - where: Space test
      line: ADC (CR-39) flew on the MISSE 2 PEACE tray on the ISS from 2001 to 2005, with an erosion yield greater than 6.80e-24 cm3/atom.
  compare: The patent comparison puts CR-39 at 91 % light transmittance and a 1.498 refractive index. These are single comparative examples, so they are examples rather than a ranking against other optical plastics.
  compare_rows:
    - scope: material
      label: Density
      benchmark: density
    - scope: material
      label: Light transmittance
      benchmark: light_transmittance
    - scope: material
      label: Atomic oxygen erosion yield
      benchmark: atomic_oxygen_erosion_yield
  handling:
    - Keep continuous use at 100 °C or below. Expect UV to change optical absorption at 254 nm.
  good_for:
    - 'Light optical parts: 1.498 refractive index and 91 % light transmittance in the patent comparison.'
    - 'Track detection: 3 % energy resolution for 2.9 MeV protons in the track-detector study.'
    - 'Weight: about half the weight of glass for eyeglass lenses (Wikipedia).'
  watch_out:
    - 'Atomic oxygen: the MISSE 2 sample eroded through, with an erosion yield greater than 6.80e-24 cm3/atom.'
    - 'UV at 254 nm: optical absorption reaches 54 cm-1 in the 215-242 nm band, and etch behaviour changes.'
    - 'Monomer hazards: H302, H315 and H410 apply to the liquid monomer, and the cured polymer was not classified.'
  verdict: CR-39 is a clear, light thermoset with 1.498 refractive index, 91 % light transmittance and 100 °C continuous use, which suits eyeglass lenses and track detection. It is weak in low Earth orbit, where the MISSE 2 sample eroded through, and under short-wavelength UV.