{
  "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)",
    "designations": [],
    "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,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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",
        "year": 2008,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "density",
      "label": "Specific gravity, CR-39 comparative example",
      "value": 1.32,
      "bound": "exact",
      "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)",
      "source_detail": {
        "title": "US5350822, High refractive index plastic lens composition (Table 1 and Table 3, CR-39 comparative example)",
        "url": "https://patents.google.com/patent/US5350822",
        "year": 1994,
        "kind": "paper",
        "license": "patent document (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, liquid monomer ADC",
      "value": 1.143,
      "bound": "exact",
      "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)",
      "source_detail": {
        "title": "Diallyl diglycol carbonate (ADC monomer), Wikipedia (monomer properties, GHS hazards, suppliers)",
        "url": "https://en.wikipedia.org/wiki/Allyl_diglycol_carbonate",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index, cured CR-39",
      "value": 1.498,
      "bound": "exact",
      "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",
      "source_detail": {
        "title": "US5350822, High refractive index plastic lens composition (Table 1 and Table 3, CR-39 comparative example)",
        "url": "https://patents.google.com/patent/US5350822",
        "year": 1994,
        "kind": "paper",
        "license": "patent document (cited, not reproduced)"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index, monomer ADC",
      "value": 1.45,
      "bound": "exact",
      "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)",
      "source_detail": {
        "title": "Diallyl diglycol carbonate (ADC monomer), Wikipedia (monomer properties, GHS hazards, suppliers)",
        "url": "https://en.wikipedia.org/wiki/Allyl_diglycol_carbonate",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0"
      }
    },
    {
      "benchmark": "light_transmittance",
      "label": "Light transmittance, CR-39 comparative example",
      "value": 91,
      "bound": "exact",
      "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)",
      "source_detail": {
        "title": "US5350822, High refractive index plastic lens composition (Table 1 and Table 3, CR-39 comparative example)",
        "url": "https://patents.google.com/patent/US5350822",
        "year": 1994,
        "kind": "paper",
        "license": "patent document (cited, not reproduced)"
      }
    },
    {
      "benchmark": "light_transmittance",
      "label": "Light transmittance, commercial ADC plates",
      "value": 92,
      "bound": "exact",
      "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",
      "source_detail": {
        "title": "US6417273, Monomer composition for optical plastic material (Table 4, commercial ADC plates)",
        "url": "https://patents.google.com/patent/US6417273B1/en",
        "year": 2002,
        "kind": "paper",
        "license": "patent document (cited, not reproduced)"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Heat resistance, equal to the glass transition per the source",
      "value": 91,
      "bound": "exact",
      "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",
      "source_detail": {
        "title": "US6417273, Monomer composition for optical plastic material (Table 4, commercial ADC plates)",
        "url": "https://patents.google.com/patent/US6417273B1/en",
        "year": 2002,
        "kind": "paper",
        "license": "patent document (cited, not reproduced)"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Continuous use temperature",
      "value": 100,
      "bound": "exact",
      "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",
      "source_detail": {
        "title": "CR-39, Wikipedia (density, refractive index, Abbe number, heat limits, optics and detector use, history)",
        "url": "https://en.wikipedia.org/wiki/CR-39",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0"
      }
    },
    {
      "benchmark": "cte",
      "label": "Linear expansion coefficient, CR-39 comparative example",
      "value": 117,
      "bound": "exact",
      "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)",
      "source_detail": {
        "title": "US5350822, High refractive index plastic lens composition (Table 1 and Table 3, CR-39 comparative example)",
        "url": "https://patents.google.com/patent/US5350822",
        "year": 1994,
        "kind": "paper",
        "license": "patent document (cited, not reproduced)"
      }
    },
    {
      "benchmark": "moisture_absorption",
      "label": "Water absorption, CR-39 comparative example",
      "value": 0.2,
      "bound": "exact",
      "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)",
      "source_detail": {
        "title": "US5350822, High refractive index plastic lens composition (Table 1 and Table 3, CR-39 comparative example)",
        "url": "https://patents.google.com/patent/US5350822",
        "year": 1994,
        "kind": "paper",
        "license": "patent document (cited, not reproduced)"
      }
    },
    {
      "benchmark": "atomic_oxygen_erosion_yield",
      "label": "Atomic oxygen erosion yield, MISSE 2 (lower bound)",
      "value": 6.8e-24,
      "bound": "lower",
      "unit": "cm3/atom",
      "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",
      "source_detail": {
        "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",
        "year": 2008,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "atomic_oxygen_erosion_yield",
      "label": "Atomic oxygen erosion yield, predicted",
      "value": 6.3e-24,
      "bound": "exact",
      "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",
      "source_detail": {
        "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",
        "year": 2008,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "molar_mass",
      "label": "Molar mass, repeat unit C12H18O7",
      "value": 274.27,
      "bound": "exact",
      "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",
      "source_detail": {
        "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",
        "year": 2008,
        "kind": "report",
        "license": "public domain (NASA)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, monomer ADC",
      "value": -4,
      "bound": "exact",
      "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)",
      "source_detail": {
        "title": "Diallyl diglycol carbonate (ADC monomer), Wikipedia (monomer properties, GHS hazards, suppliers)",
        "url": "https://en.wikipedia.org/wiki/Allyl_diglycol_carbonate",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0"
      }
    },
    {
      "benchmark": "optical_absorption_coefficient",
      "label": "Optical absorption coefficient, UV-C band (215-242 nm)",
      "value": 54,
      "bound": "exact",
      "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",
      "source_detail": {
        "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",
        "year": 2011,
        "kind": "paper",
        "license": "open-access article (cited, not reproduced)"
      }
    },
    {
      "benchmark": "optical_absorption_coefficient",
      "label": "Optical absorption coefficient, UV-A band (315-400 nm)",
      "value": 1,
      "bound": "exact",
      "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",
      "source_detail": {
        "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",
        "year": 2011,
        "kind": "paper",
        "license": "open-access article (cited, not reproduced)"
      }
    },
    {
      "benchmark": "energy_resolution",
      "label": "Energy resolution, 2.9 MeV protons",
      "value": 3,
      "bound": "exact",
      "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",
      "source_detail": {
        "title": "CR-39 track detector for multi-MeV ion spectroscopy, PMC open-access article",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC5438376/",
        "year": 2017,
        "kind": "paper",
        "license": "open-access article (cited, not reproduced)"
      }
    },
    {
      "benchmark": "polymerization_time",
      "label": "Polymerization time, CR-39 comparative example",
      "value": 18,
      "bound": "exact",
      "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",
      "source_detail": {
        "title": "US5350822, High refractive index plastic lens composition (Table 1 and Table 3, CR-39 comparative example)",
        "url": "https://patents.google.com/patent/US5350822",
        "year": 1994,
        "kind": "paper",
        "license": "patent document (cited, not reproduced)"
      }
    }
  ],
  "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"
      }
    ],
    "side_effects": [],
    "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)"
      }
    ],
    "mitigations": []
  },
  "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)",
      "producers": [
        {
          "country": "United States"
        }
      ],
      "critical_lists": [],
      "substitutes": [],
      "source": "wikipedia-cr39",
      "where": "History and trademark sections"
    },
    {
      "subject": "CR-39 track detectors (sold to researchers)",
      "producers": [
        {
          "country": "United Kingdom"
        },
        {
          "country": "United States"
        },
        {
          "country": "Japan"
        }
      ],
      "critical_lists": [],
      "substitutes": [],
      "source": "wikipedia-adc",
      "where": "Suppliers (radiation detection section)"
    }
  ],
  "media": [],
  "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."
  ],
  "story": {
    "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.",
    "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."
      }
    ],
    "can_do": [
      {
        "label": "Let light through",
        "line": "The CR-39 comparative example in the patent transmits 91 % of light, and a commercial 2 mm ADC plate transmits 92 %.",
        "benchmark": "light_transmittance",
        "scope": "material",
        "value": "91 % light transmittance"
      },
      {
        "label": "Bend light well",
        "line": "The cured plastic has a refractive index of 1.498, close to the value for crown glass, per Wikipedia.",
        "benchmark": "refractive_index",
        "scope": "material",
        "value": "1.498 refractive index"
      },
      {
        "label": "Detect particles",
        "line": "The track-detector study reports 3 % energy resolution for 2.9 MeV protons and 4 % for 3.15 MeV.",
        "benchmark": "energy_resolution",
        "scope": "material",
        "value": "3 % energy resolution for 2.9 MeV protons"
      },
      {
        "label": "Stay clear in heat",
        "line": "CR-39 is rated for continuous use up to 100 °C, and up to one hour at 130 °C per Wikipedia (citation needed).",
        "benchmark": "max_service_temp",
        "scope": "material",
        "value": "100 °C continuous use"
      }
    ],
    "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": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Light transmittance",
        "benchmark": "light_transmittance",
        "scope": "material"
      },
      {
        "label": "Atomic oxygen erosion yield",
        "benchmark": "atomic_oxygen_erosion_yield",
        "scope": "material"
      }
    ],
    "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.",
    "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.",
        "points": [
          {
            "label": "Liquid monomer",
            "line": "Diallyl diglycol carbonate has GHS statements H302, H315 and H410 with signal word Warning (Wikipedia)."
          }
        ],
        "level": 1,
        "verdict": "Monomer hazardous, polymer not classified"
      },
      {
        "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)."
          }
        ]
      }
    ]
  },
  "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."
  },
  "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",
      "year": 2008,
      "kind": "report",
      "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",
      "year": 2026,
      "kind": "web",
      "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",
      "year": 2026,
      "kind": "web",
      "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",
      "year": 2026,
      "kind": "web",
      "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",
      "year": 1994,
      "kind": "paper",
      "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",
      "year": 2002,
      "kind": "paper",
      "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/",
      "year": 2017,
      "kind": "paper",
      "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",
      "year": 2011,
      "kind": "paper",
      "license": "open-access article (cited, not reproduced)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/adc-cr-39/"
}