spore: profile
id: polycarbonate
spore_version: 0.2
family: engineering-polymers
name: Polycarbonate (bisphenol-A)
abbreviation: PC
role: tough, transparent housing and optical polymer
category: polymers
type: polycarbonates
summary: |
  Bisphenol-A polycarbonate (PC) is a tough, transparent thermoplastic used for electronics housings, covers and optical parts. Covestro's Makrolon 2207 MAS195, a UV-stabilised injection-moulding grade, has a density of 1190 kg/m3, a Vicat softening temperature of 143 °C and a tensile modulus of 2400 MPa. SABIC's LEXAN VISUALFX FXE154 has a refractive index of 1.59 and 88 % light transmittance. In orbit, PC has flown on MISSE 2, where the passport records an atomic-oxygen erosion yield of 4.29e-24 cm3/atom, and accelerated weathering shows that UV yellowing starts at the surface.
best_for: 'Tough, transparent housings and light covers: 89 % luminous transmittance, 55 J puncture energy at 23 °C and 1190 kg/m3 density in the Covestro injection-moulding grades'
weakest_at: 'Ultraviolet light: PC yellows under UV, with an activation energy of about 21 kJ/mol for the yellowing (Pickett 2019), and atomic oxygen in low Earth orbit erodes it (MISSE 2)'
identity:
  formula: Bisphenol-A polycarbonate, a thermoplastic polymer; the repeat-unit formula is not printed in the pages read for this profile
  source: covestro-makrolon-2207
  where: Product description of Makrolon 2207 MAS195 on the Covestro Solutions page (polycarbonate for injection moulding, UV-stabilised, transparent)
tags:
  environments:
    - low-earth-orbit
  stresses:
    - atomic-oxygen
    - uv
    - vacuum-and-outgassing
  applications:
    - electronics-and-chips
    - optics-and-cameras
properties:
  - benchmark: density
    label: Density, Makrolon 2207 MAS195
    value: 1190
    unit: kg/m3
    scope: material
    conditions:
      grade: Makrolon 2207 MAS195 (Covestro)
      temperature: not stated
    method: Value printed in a manufacturer product page (ISO 1183-1)
    status: ground
    source: covestro-makrolon-2207
    where: Other properties table, row Density, printed as 1,190 kg/m³
  - benchmark: melt_volume_flow_rate
    label: Melt volume-flow rate, Makrolon 2207 MAS195
    value: 34
    unit: cm3/10 min
    scope: material
    conditions:
      grade: Makrolon 2207 MAS195 (Covestro)
      temperature: 300 °C
      load: 1.2 kg
    method: Value printed in a manufacturer product page (ISO 1133-1)
    status: ground
    source: covestro-makrolon-2207
    where: Rheological properties table, row Melt Volume-flow Rate (MVR)
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, Makrolon 2207 MAS195
    value: 144
    unit: °C
    scope: material
    conditions:
      grade: Makrolon 2207 MAS195 (Covestro)
      heating_rate: 10 °C/min
    method: Value printed in a manufacturer product page (ISO 11357-1,-2)
    status: ground
    source: covestro-makrolon-2207
    where: Thermal properties table, row Glass Transition Temperature
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, Makrolon 1260
    value: 142
    unit: °C
    scope: material
    conditions:
      grade: Makrolon 1260 (Covestro)
      heating_rate: 10 °C/min
    method: Value printed in a materials database entry for the grade (ISO 11357-1,-2)
    status: ground
    source: mdc-makrolon-1260
    where: Thermal section, row Glass transition temperature (table with ISO 11357-1/-2 standard)
  - benchmark: vicat_softening_temperature
    label: Vicat softening temperature, Makrolon 2207 MAS195
    value: 143
    unit: °C
    scope: material
    conditions:
      grade: Makrolon 2207 MAS195 (Covestro)
      load: 50 N
      heating_rate: 50 °C/h
    method: Value printed in a manufacturer product page (ISO 306)
    status: ground
    source: covestro-makrolon-2207
    where: Thermal properties table, row Vicat Softening Temperature, condition 50 N; 50 °C/h
  - benchmark: heat_deflection_temperature
    label: Heat deflection temperature at 1.80 MPa, Makrolon 2207 MAS195
    value: 123
    unit: °C
    scope: material
    conditions:
      grade: Makrolon 2207 MAS195 (Covestro)
      stress: 1.80 MPa
    method: Value printed in a manufacturer product page (ISO 75-1,-2)
    status: ground
    source: covestro-makrolon-2207
    where: Thermal properties table, row Heat Deflection Temp. (HDT) at 1.80 MPa
  - benchmark: elastic_modulus
    label: Tensile modulus, Makrolon 2207 MAS195
    value: 2400
    unit: MPa
    scope: material
    conditions:
      grade: Makrolon 2207 MAS195 (Covestro)
      temperature: 23 °C
      speed: 1 mm/min
    method: Value printed in a manufacturer product page (ISO 527-1,-2)
    status: ground
    source: covestro-makrolon-2207
    where: Mechanical properties table, row Tensile Modulus
  - benchmark: yield_strength
    label: Yield stress, Makrolon 2207 MAS195
    value: 65
    unit: MPa
    scope: material
    conditions:
      grade: Makrolon 2207 MAS195 (Covestro)
      temperature: 23 °C
      speed: 50 mm/min
    method: Value printed in a manufacturer product page (ISO 527-1,-2)
    status: ground
    source: covestro-makrolon-2207
    where: Mechanical properties table, row Yield Stress
  - benchmark: elongation
    label: Strain at break, Makrolon 2207 MAS195
    value: 120
    unit: '%'
    scope: material
    conditions:
      grade: Makrolon 2207 MAS195 (Covestro)
      temperature: 23 °C
      speed: 50 mm/min
    method: Value printed in a manufacturer product page (ISO 527-1,-2)
    status: ground
    source: covestro-makrolon-2207
    where: Mechanical properties table, row Strain at Break
  - benchmark: elastic_modulus
    label: Flexural modulus, Makrolon 2207 MAS195
    value: 2350
    unit: MPa
    scope: material
    conditions:
      grade: Makrolon 2207 MAS195 (Covestro)
      temperature: 23 °C
      speed: 2 mm/min
    method: Value printed in a manufacturer product page (ISO 178)
    status: ground
    source: covestro-makrolon-2207
    where: Mechanical properties table, row Flexural Modulus
  - benchmark: flexural_strength
    label: Flexural strength, Makrolon 3207
    value: 97
    unit: MPa
    scope: material
    conditions:
      grade: Makrolon 3207 (Covestro)
      temperature: 23 °C
    method: Value printed in a materials database entry for the grade (ISO 178)
    status: ground
    source: mdc-makrolon-3207
    where: Mechanical section, row Flexural strength
  - benchmark: impact_energy
    label: Puncture energy at 23 °C, Makrolon 2207 MAS195
    value: 55
    unit: J
    scope: material
    conditions:
      grade: Makrolon 2207 MAS195 (Covestro)
      temperature: 23 °C
      test: ISO 6603-2 puncture
    method: Value printed in a manufacturer product page (ISO 6603-2)
    status: ground
    source: covestro-makrolon-2207
    where: Mechanical properties table, row Puncture Energy, 23 °C
  - benchmark: light_transmittance
    label: Luminous transmittance, Makrolon 2656
    value: 89
    unit: '%'
    scope: material
    conditions:
      grade: Makrolon 2656 (Covestro)
      thickness: not stated
    method: Value printed in a materials database entry for the grade (ISO 13468-1,-2)
    status: ground
    source: mdc-makrolon-2656
    where: Optical section, row Luminous transmittance
  - benchmark: light_transmittance
    label: Light transmittance, LEXAN VISUALFX FXE154
    value: 88
    unit: '%'
    scope: material
    conditions:
      grade: LEXAN VISUALFX FXE154 (SABIC)
      thickness: not stated
    method: Value printed in a materials database entry for the grade (ASTM D1003)
    status: ground
    source: mdc-lexan-fxe154
    where: Optical section, row Light Transmittance
  - benchmark: refractive_index
    label: Index of refraction, LEXAN VISUALFX FXE154
    value: 1.59
    unit: dimensionless
    scope: material
    conditions:
      grade: LEXAN VISUALFX FXE154 (SABIC)
      wavelength: not stated
    method: Value printed in a materials database entry for the grade (ASTM D542)
    status: ground
    source: mdc-lexan-fxe154
    where: Optical section, row Index of Refraction
  - benchmark: water_absorption
    label: Water absorption at equilibrium, LEXAN VISUALFX FXE154
    value: 0.58
    unit: '%'
    scope: material
    conditions:
      grade: LEXAN VISUALFX FXE154 (SABIC)
      condition: equilibrium
    method: Value printed in a materials database entry for the grade (ASTM D570)
    status: ground
    source: mdc-lexan-fxe154
    where: Other section, row Water Absorption, Equilibrium
  - benchmark: relative_permittivity
    label: Relative permittivity at 100 Hz, Makrolon 2207 MAS195
    value: 3.1
    unit: dimensionless
    scope: material
    conditions:
      grade: Makrolon 2207 MAS195 (Covestro)
      frequency: 100 Hz
      humidity: 23 °C, 50 % r.h.
    method: Value printed in a manufacturer product page (IEC 60250)
    status: ground
    source: covestro-makrolon-2207
    where: Electrical properties table, row Relative Permittivity, 100 Hz
  - benchmark: oxygen_index
    label: Oxygen index, Makrolon 2207 MAS195
    value: 28
    unit: '%'
    scope: material
    conditions:
      grade: Makrolon 2207 MAS195 (Covestro)
      method: Method A
    method: Value printed in a manufacturer product page (ISO 4589-2)
    status: ground
    source: covestro-makrolon-2207
    where: Thermal properties table, row Oxygen Index, Method A
  - benchmark: activation_energy
    label: Activation energy for yellowing (delta E), polycarbonate under accelerated weathering
    value: 21
    unit: kJ/mol
    scope: material
    conditions:
      material: injection-moulded PC chips, 3.2 mm thick, 97 % PC and 3 % TiO2
      exposure: NIST SPHERE accelerated weathering, full irradiance about 150 W/m2 over 295 to 400 nm, 35 to 70 °C
    method: Fitted value printed in a paper (95 % confidence limit reported as plus or minus 2 kJ/mol)
    status: ground
    note: Plus or minus 2 kJ/mol (95 % confidence limit) as printed; the abstract gives the same value as about 20 kJ/mol.
    source: pickett2019
    where: Section 3.2, Table 3, row PC Delta E
  - benchmark: atomic_oxygen_erosion_yield
    label: Atomic oxygen erosion yield, polycarbonate, MISSE 2 PEACE
    value: 4.29e-24
    unit: cm3/atom
    scope: material
    conditions:
      exposure: ISS, MISSE 2 PEACE tray 1, 2001-08-16 to 2005-07-30 (3.95 years)
      fluence: 8.43e21 atoms/cm2
    method: Measured on MISSE 2 flight samples and listed in NASA TM-2008-215490, Table I
    status: flight
    note: Value read in Table I of NASA/TM-2008-215490 (PC, 4.29e-24 cm3/atom) in a later manual check.
    source: ntrs-tm2008
    where: Passport misse2-pc results block (cites Table I of NASA/TM-2008-215490)
corrosion:
  - environment: UV light (accelerated weathering, Earth exposure simulated)
    headline: PC yellows under UV, and the damage starts on the surface.
    effect: Pickett et al. found that most PC photodegradation happens in the top 25 µm of the surface, and that the yellowing activation energy is about 21 kJ/mol. A TiO2-pigmented PC absorbs UV below 380 nm.
    rating: moderate
    conditions:
      exposure: NIST SPHERE accelerated weathering, about 150 W/m2, 295 to 400 nm
      material: injection-moulded PC chips, 3.2 mm, 97 % PC and 3 % TiO2
    source: pickett2019
    where: Abstract, section 3 (Results), section 3.2 Table 3
risks:
  hazards:
    - text: 'Bisphenol A (CID 6623): PubChem aggregated GHS lists H317 (99.9 % of notifications), H318 (99.9 %), H335 (99.3 %), H360 (19.4 %), H361 (78 %) and H411 (12.2 %), with signal word Danger. This describes the monomer, not the polymer.'
      ghs:
        - H317
        - H318
        - H335
        - H360
        - H361
        - H411
      source: pubchem-bpa
      where: Safety and Hazards, GHS Classification (aggregated, CID 6623)
    - text: Bisphenol A is described as a xenoestrogen that mimics the effects of estrogen in the body (Wikipedia, Bisphenol A). Read as a health concern for the monomer, not a hazard statement for the polymer.
      ghs: []
      source: wikipedia-bpa
      where: Introduction
    - text: No GHS classification or SDS for the bisphenol-A polycarbonate polymer was read in this run, so the polymer is not classed from its monomer alone.
      ghs: []
      source: wikipedia-polycarbonate
      where: Production section (no hazard data printed)
  failure_risks:
    - mode: UV yellowing of PC surfaces
      trigger: Long exposure to UV light, as in an unshielded window or cover
      consequence: The surface yellows and loses light transmission over time. The paper gives the activation energy for this change, not a rate for any specific service life.
      severity: moderate
      source: pickett2019
      where: Abstract and section 3
  handling:
    - text: Use UV-stabilised grades for parts exposed to sunlight. The Covestro grade Makrolon 2207 MAS195 is described as UV-stabilised.
      source: covestro-makrolon-2207
      where: Product description on the Covestro Solutions page
uses:
  - application: electronics-and-chips
    device: Injection-moulded housings and covers
    example: Makrolon 2207 MAS195 is a low-viscosity injection-moulding grade with easy release, available transparent, translucent and opaque.
    source: covestro-makrolon-2207
    where: Product description and datasheet tables
  - application: optics-and-cameras
    device: Optical and light-transmitting parts
    example: LEXAN VISUALFX FXE154 has 88 % light transmittance and a refractive index of 1.59; Makrolon 2656 has 89 % luminous transmittance.
    source: mdc-lexan-fxe154
    where: Product description and datasheet tables
  - application: electronics-and-chips
    device: Electrical insulation
    example: Makrolon 2207 MAS195 has a relative permittivity of 3.1 at 100 Hz.
    source: covestro-makrolon-2207
    where: Product description and datasheet tables
  - application: structures
    device: Space exposure (flown test)
    example: PC was one of the polymers on the MISSE 2 PEACE tray on the ISS from 2001 to 2005; the passport records its atomic-oxygen erosion yield.
    source: ntrs-tm2008
    where: Product description and datasheet tables
supply:
  - subject: Bisphenol A (monomer for polycarbonate)
    demand: Global production was estimated at about 10 million tonnes in 2022 (Wikipedia, citing Abraham and Chakraborty 2020).
    producers: []
    critical_lists: []
    substitutes: []
    source: wikipedia-bpa
    where: Introduction and Production section
  - subject: Polycarbonate (bisphenol-A based)
    demand: About one billion kilograms of polycarbonate is produced annually (Wikipedia). No year is printed.
    producers:
      - name: Bayer
        note: Began commercial production under the Makrolon name in 1958 after a 1953 patent (history; no current volume read)
        country: Bayer
      - name: General Electric
        note: Began production under the Lexan name in 1960 (history; no current volume read)
        country: General Electric
    critical_lists: []
    substitutes: []
    source: wikipedia-polycarbonate
    where: History and Production sections
documents:
  - title: Makrolon 2207 MAS195 product page, Covestro Solutions
    type: datasheet
    url: https://solutions.covestro.com/en/products/makrolon/makrolon-2207-mas195_000000000086918005
  - title: Makrolon 2656 properties, Material Data Center (Covestro)
    type: database
    url: https://www.materialdatacenter.com/ms/en/Makrolon/Covestro+Deutschland+AG/Makrolon®+2656/1a03032f/410
  - title: Makrolon 3207 properties, Material Data Center (Covestro)
    type: database
    url: https://www.materialdatacenter.com/ms/en/Makrolon/Covestro+Deutschland+AG/Makrolon®+3207/deeb0dbc/410
  - title: Makrolon 1260 properties, Material Data Center (Covestro)
    type: database
    url: https://materialdatacenter.com/ms/en/Makrolon/Covestro+Deutschland+AG/Makrolon®+1260/58c418f1/410
  - title: LEXAN VISUALFX FXE154 properties, Material Data Center (SABIC)
    type: database
    url: https://www.materialdatacenter.com/ms/en/Lexan/SABIC+Innovative+Plastics/LEXAN%E2%84%A2+VISUALFX%E2%84%A2+Resin+FXE154/91c6c687/1122
  - title: Ge et al., Structure and Properties of Bisphenol A Polycarbonate Exposed to Ultraviolet, Applied Mechanics and Materials 377 (2013)
    type: paper
    url: https://www.scientific.net/AMM.377.255
    year: 2013
  - title: Pickett et al., Accelerated weathering parameters for some aromatic engineering thermoplastics, Polymer Degradation and Stability 166 (2019)
    type: paper
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC7539635
    year: 2019
  - 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
gaps:
  - No PC-specific atomic-oxygen erosion yield was read from the NASA table. The 4.29e-24 cm3/atom value is taken from the MISSE 2 passport and is marked cited, not verified.
  - No outgassing data (total mass loss, CVCM) for PC was found in an opened source. The NASA outgassing database did not return a PC entry in the search results.
  - The PubChem and ECHA hazard record for polycarbonate returned a verification page, so no GHS hazard classification is recorded.
  - The Pickett 2019 paper gives an activation energy and exposure conditions, not a yellowing rate, and the Ge 2013 paper's abstract gives only a depth of several micrometres with no numbers.
  - The Quickparts Makrolon 2405 PDF and the Lexan 503R PDF were not readable, so their values are not recorded.
  - No PC value for radiation dose, proton or electron damage, or cryogenic behaviour was found in an opened source.
  - No current producer volumes or country shares for bisphenol-A polycarbonate were read. The supply section gives BPA production (about 10 million tonnes, 2022) and the Bayer and GE history only. No recycling data was read.
  - CAS 25037-45-0 is not on any fetched page (PubChem name lookup for polycarbonate returned no CID; the Wikipedia infobox prints no CAS). It is not entered in identity.
  - The repeat-unit formula C16H14O3 is derived from the printed structure and the PubChem BPA formula C15H16O2; no fetched page printed it. The 254.28 g/mol molar mass is computed from NIST interval midpoints.
sources:
  covestro-makrolon-2207:
    title: Makrolon 2207 MAS195, product page, Covestro Solutions
    url: https://solutions.covestro.com/en/products/makrolon/makrolon-2207-mas195_000000000086918005
    kind: datasheet
    license: Manufacturer product page (cited, not reproduced)
  mdc-makrolon-2656:
    title: Makrolon 2656 properties, Material Data Center (Covestro grade data)
    url: https://www.materialdatacenter.com/ms/en/Makrolon/Covestro+Deutschland+AG/Makrolon®+2656/1a03032f/410
    kind: database
    license: Material Data Center page (cited, not reproduced)
  mdc-makrolon-3207:
    title: Makrolon 3207 properties, Material Data Center (Covestro grade data)
    url: https://www.materialdatacenter.com/ms/en/Makrolon/Covestro+Deutschland+AG/Makrolon®+3207/deeb0dbc/410
    kind: database
    license: Material Data Center page (cited, not reproduced)
  mdc-makrolon-1260:
    title: Makrolon 1260 properties, Material Data Center (Covestro grade data)
    url: https://materialdatacenter.com/ms/en/Makrolon/Covestro+Deutschland+AG/Makrolon®+1260/58c418f1/410
    kind: database
    license: Material Data Center page (cited, not reproduced)
  mdc-lexan-fxe154:
    title: LEXAN VISUALFX FXE154 properties, Material Data Center (SABIC grade data)
    url: https://www.materialdatacenter.com/ms/en/Lexan/SABIC+Innovative+Plastics/LEXAN%E2%84%A2+VISUALFX%E2%84%A2+Resin+FXE154/91c6c687/1122
    kind: database
    license: Material Data Center page (cited, not reproduced)
  pickett2019:
    title: Pickett et al., Accelerated weathering parameters for some aromatic engineering thermoplastics, Polymer Degradation and Stability 166 (2019)
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC7539635
    year: 2019
    kind: paper
    license: Open-access article (cited, not reproduced)
  ntrs-tm2008:
    title: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit (Banks, Backus, de Groh), NASA/TM-2008-215490
    url: https://ntrs.nasa.gov/citations/20090011780
    year: 2008
    kind: report
    license: public domain (NASA)
  pubchem-bpa:
    title: 'PubChem CID 6623, Bisphenol A: GHS Classification (aggregated)'
    url: https://pubchem.ncbi.nlm.nih.gov/compound/6623
    kind: database
    year: 2026
    license: public domain (NIH PubChem)
  wikipedia-bpa:
    title: Bisphenol A, Wikipedia (production volume, molar mass, xenoestrogen statement)
    url: https://en.wikipedia.org/wiki/Bisphenol_A
    kind: web
    year: 2026
    license: CC BY-SA 4.0
  wikipedia-polycarbonate:
    title: Polycarbonate, Wikipedia (repeat unit, production routes, volume, producers)
    url: https://en.wikipedia.org/wiki/Polycarbonate
    kind: web
    year: 2026
    license: CC BY-SA 4.0
  nist-atomic-weights:
    title: 'NIST, Atomic Weights and Isotopic Compositions for All Elements (C, H, O): C [12.0096, 12.0116], H [1.00784, 1.00811], O [15.99903, 15.99977]'
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&all=all&ascii=html
    kind: database
    year: 2026
    license: public domain (NIST)
license: CC-BY-4.0
updated: '2026-10-18'
review:
  status: draft
  method: assistant
  checked_values: 20
  unreachable: 3
  caveats: 4
  note: 'Values were read by an AI assistant on 2026-10-18 from the pages named in each entry. Unreachable or unreadable: the Quickparts Makrolon 2405 PDF (binary), the NASA full-text PDF for Table I (binary), and PubChem (verification page). The MISSE 2 erosion yield is cited from the project passport and is not verified against the NASA table. The Makrolon 2656 and 3207 values are from Material Data Center, a reseller page of Covestro data, not the Covestro PDF.'
story:
  recipe:
    line: Polycarbonate is made from bisphenol A (C15H16O2, PubChem CID 6623). The main route reacts bisphenol A with phosgene (COCl2) to give the polymer and sodium chloride (Wikipedia, Polycarbonate). An alternative melt route transesterifies bisphenol A with diphenyl carbonate and releases phenol (Wikipedia). The repeat unit is [OC(OC6H4)2CMe2]n, a carbonate linkage between bisphenol A units, and by atom count it is C16H14O3 (derived from the printed structure and the BPA formula; no fetched page printed this formula).
    parts:
      - name: Bisphenol A
        symbol: BPA
        role: Diol monomer. Its two phenol groups link through carbonate groups.
        share_note: atoms C15H16O2
      - name: Phosgene
        symbol: COCl2
        role: Carbonyl source in the interfacial route. Its byproduct is sodium chloride (Wikipedia net reaction).
        share_note: atoms CCl2O
      - name: Carbon
        symbol: C
        atoms: 16
        atomic_weight: 12.0106
        role: Backbone of the repeat unit. Atomic weight is the midpoint of the NIST interval (see source nist-atomic-weights).
      - name: Hydrogen
        symbol: H
        atoms: 14
        atomic_weight: 1.00797
        role: Methyl and aromatic hydrogens. Atomic weight is the midpoint of the NIST interval (see source nist-atomic-weights).
      - name: Oxygen
        symbol: O
        atoms: 3
        atomic_weight: 15.9994
        role: Carbonate oxygens. Atomic weight is the midpoint of the NIST interval (see source nist-atomic-weights).
    molar_mass_note: Computed from C16H14O3 with the NIST midpoints; see gaps for the value.
  risk_groups:
    - title: For people
      lead: No hazard classification for polycarbonate was verified in this run, because the PubChem and ECHA pages were not readable.
      level: 1
      verdict: Not verified
      points:
        - label: Polycarbonate as a material
          line: The Covestro and SABIC grades read here are sold for injection moulding and optics. Their data sheets give no hazard statements, and no ECHA classification was read.
    - title: If it fails
      lead: The sources describe UV yellowing and atomic-oxygen erosion. Only the erosion value comes from a flight, and it is cited from the passport.
      points:
        - label: UV yellowing
          line: Pickett et al. give an activation energy of 21 kJ/mol for yellowing of PC under accelerated weathering, with most change in the top 25 µm.
        - label: Atomic oxygen in orbit
          line: The MISSE 2 passport records an erosion yield of 4.29e-24 cm3/atom after 3.95 years on the ISS, from a cited NASA table that was not opened here.
    - title: Handling and storage
      points:
        - label: Use the right grade
          line: Choose a UV-stabilised grade such as Makrolon 2207 MAS195 for parts that see sunlight.
  why: Polycarbonate is a tough, transparent thermoplastic. The Covestro injection-moulding grade Makrolon 2207 MAS195 has a density of 1190 kg/m3, a melt volume-flow rate of 34 cm3/10 min, a Vicat softening temperature of 143 °C and a tensile modulus of 2400 MPa. SABIC's LEXAN VISUALFX FXE154 transmits 88 % of light and has a refractive index of 1.59. These numbers make PC a practical choice for housings, covers and light-transmitting parts.
  can_do:
    - label: Be tough
      value: 55 J puncture energy at 23 °C
      benchmark: impact_energy
      line: Makrolon 2207 MAS195 absorbs 55 J in the ISO 6603-2 puncture test at 23 °C.
    - label: Let light through
      value: 89 % luminous transmittance
      benchmark: light_transmittance
      line: Makrolon 2656 transmits 89 % of luminous light, and LEXAN VISUALFX FXE154 transmits 88 %.
    - label: Stay stiff
      value: 2400 MPa tensile modulus
      benchmark: elastic_modulus
      line: Makrolon 2207 MAS195 has a tensile modulus of 2400 MPa and a flexural modulus of 2350 MPa.
    - label: Stay solid when warm
      value: 123 °C HDT at 1.80 MPa
      benchmark: heat_deflection_temperature
      line: Heat deflection temperature at 1.80 MPa is 123 °C, and the Vicat softening temperature is 143 °C.
  uses:
    - where: Housings and covers
      line: Makrolon 2207 MAS195 is a UV-stabilised injection-moulding grade, available transparent, translucent and opaque.
    - where: Optics
      line: LEXAN VISUALFX FXE154 has a refractive index of 1.59 and 88 % light transmittance.
    - where: Space test
      line: PC flew on the MISSE 2 PEACE tray on the ISS from 2001 to 2005. The passport records its erosion yield, which is cited and not verified here.
  compare: Makrolon 2207 MAS195 has a density of 1190 kg/m3 and LEXAN VISUALFX FXE154 transmits 88 % of light. These are single grades from two makers, so read them as examples rather than a ranking against other polymers.
  compare_rows:
    - scope: material
      label: Density
      benchmark: density
    - scope: material
      label: Light transmittance
      benchmark: light_transmittance
    - scope: material
      label: Vicat softening
      benchmark: vicat_softening_temperature
  handling:
    - Choose a UV-stabilised grade for sunlit parts, since PC yellows under UV.
  good_for:
    - 'Tough, transparent covers: 55 J puncture energy and 89 % luminous transmittance in the Covestro grades.'
    - 'Heat-resistant housings: 143 °C Vicat softening temperature for Makrolon 2207 MAS195.'
    - 'Electrical insulation: 3.1 relative permittivity at 100 Hz for Makrolon 2207 MAS195.'
  watch_out:
    - 'UV yellowing: PC yellows in sunlight, with an activation energy of 21 kJ/mol for the change.'
    - 'Atomic oxygen: the MISSE 2 passport records an erosion yield of 4.29e-24 cm3/atom, cited and not verified here.'
    - 'Hazard data: no ECHA or PubChem classification was verified in this run.'
  verdict: Polycarbonate is a tough, transparent, heat-resistant housing and optical polymer, with 89 % transmittance, 55 J puncture energy and 143 °C Vicat softening in the Covestro grades. It yellows under UV and erodes under atomic oxygen in orbit, so it needs a UV-stabilised grade and a space test before flight use.