spore: profile
id: pi-pmr-15
spore_version: 0.2
family: polyimides
name: High temperature polyimide resin (PMR-15)
abbreviation: PI (PMR-15)
role: high-temperature structural matrix resin for composites
category: polymers
type: polyimides
summary: |
  PMR-15 is NASA's polymerization of monomer reactants polyimide, a thermoset resin made by curing a mix of three monomers (MDA, BTDE and NE) into a crosslinked polyimide. The neat resin has a density of 1.287 g/cm3 and a glass transition temperature of 332 degC, and NASA's own work gives 316 degC as the highest temperature for structures. In low Earth orbit the MISSE 2 flight on the ISS eroded it at more than 3.02e-24 cm3/atom, and the sample was eroded through, so the true yield is higher. The monomer MDA is a suspect carcinogen, which is why the resin is costly to make.
best_for: Structural composite parts that must hold strength at about 290 to 316 degC, such as engine ducts, cowls and fan blades
weakest_at: Atomic-oxygen erosion in low Earth orbit (the MISSE 2 sample eroded through), and weight loss from thermo-oxidation at 316 degC; the MDA monomer is a carcinogen concern during manufacture
identity:
  formula: C95H57O14N6 (repeat unit as tabulated in the MISSE 2 report); PMR-15 is cured from MDA, BTDE and NE monomers
  source: banks2008
  where: Table IV (PI (PMR-15) formula C95H57O14N6, molecular weight 1506.5271 g/mole); monomer composition from nasa1980 and johnston2007
tags:
  environments:
    - low-earth-orbit
  stresses:
    - atomic-oxygen
  applications:
    - structures
    - propulsion-and-tanks
properties:
  - benchmark: density
    label: Density of neat resin (postcured)
    value: 1.287
    unit: g/cm3
    scope: material
    conditions:
      product: PMR-15 molding powder, neat resin disks
      postcure: 16 hr in air at 204 degC plus 24 hr in air at 316 degC
      stoichiometry: 2NE / 3.087MDA / 2.087BTDE
    method: Value printed in NASA report table of neat PMR polyimide resins
    status: ground
    source: serafini1983
    where: Table II (PMR-15 row, density column)
  - benchmark: density
    label: Density of PMR-15 (MISSE 2 reference)
    value: 1.3232
    unit: g/cm3
    scope: material
    conditions:
      product: PMR-15 sample from the MISSE 2 PEACE polymers tray
      temperature: not stated in the table
    method: Density from the MISSE 2 report, table column headed ref. 12, rho
    status: ground
    note: The neat-resin report gives 1.287 g/cm3, so the two sources differ by about 3 percent.
    source: banks2008
    where: Table II (PI (PMR-15) row)
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, neat resin
    value: 332
    unit: degC
    scope: material
    conditions:
      product: PMR-15 neat resin, postcured
      postcure: 16 hr in air at 204 degC plus 24 hr in air at 316 degC
      test: value printed in the Tg column of the neat-resin table (the header is partly garbled in the scan and is read as Tg in degC)
    method: Value printed in NASA report table of neat PMR polyimide resins
    status: ground
    source: serafini1983
    where: Table II (PMR-15 row, Tg column)
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, dry film by dynamic mechanical analysis
    value: 362
    unit: degC
    scope: material
    conditions:
      product: PMR-15 addition-cured resin, dried in an oven at 120 degC for 150 hr
      method_note: storage modulus with tan delta, scanned at 10 degC/min
    method: Value stated in NASA technical memorandum text; the authors report the Tg from this method is within 5 degC of thermo-mechanical analysis
    status: ground
    source: nasa1991
    where: Viscoelastic properties section, Figure 1 text
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, resin with absorbed moisture
    value: 349
    unit: degC
    scope: material
    conditions:
      product: PMR-15 addition-cured resin, sample held in moist conditions (above refluxing water)
      method_note: storage modulus with tan delta, scanned at 10 degC/min
    method: Value stated in NASA technical memorandum text
    status: ground
    note: The authors say the drop may be larger than shown because some moisture is lost during the ramp to Tg.
    source: nasa1991
    where: Viscoelastic properties section, Figure 1 text
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, PMR-15 graphite composite
    value: 341
    unit: degC
    scope: material
    conditions:
      product: PMR-15 unidirectional Celion 6000 graphite fibre composite
      postcure: 24 hr in air at 316 degC
      fiber_content: 60.2 (as printed in the Fiber column; the footnote says normalized to 60 vol% fiber)
    method: Value printed in NASA report table of PMR polyimide/Celion 6000 composites
    status: ground
    source: serafini1983
    where: Table IV (PMR-15 row, Tg column)
  - benchmark: max_service_temp
    label: Highest structural use temperature stated by NASA
    value: 316
    unit: degC
    scope: material
    conditions:
      product: PMR-15 composite structures, postcured
      basis: the report says the resin allows structures to be designed for use up to 316 degC
    method: Statement in NASA report text; a design statement, not a tested rating
    status: ground
    source: serafini1983
    where: Introduction (page 1 text)
  - benchmark: atomic_oxygen_erosion_yield
    label: Atomic oxygen erosion yield, MISSE 2 flight
    value: 3.02e-24
    bound: lower
    unit: cm3/atom
    scope: material
    conditions:
      experiment: MISSE 2 PEACE polymers, PEC 2 tray 1, exterior of the ISS Quest airlock
      exposure: 3.95 yr in low Earth orbit, 16 August 2001 to 30 July 2005
      fluence: 8.43e21 atoms/cm2
    method: Mass-loss erosion yield from the MISSE 2 flight sample, as printed with a greater-than sign
    status: flight
    note: The report prints a greater-than sign, so 3.02e-24 is a lower bound (the sample eroded through).
    source: banks2008
    where: Table I (PI (PMR-15) row); Section 2.1 for exposure
  - benchmark: atomic_oxygen_erosion_yield
    label: Atomic oxygen erosion yield, predicted by the NASA tool
    value: 2.27e-24
    unit: cm3/atom
    scope: material
    conditions:
      method: predictive tool based on repeat-unit chemistry, density and bond counts, fitted to the MISSE 2 data
    method: Predicted value from the NASA predictive tool, printed as the predicted column of the comparison table
    status: calculated
    note: The predicted value is 2.27e-24 against a measured lower bound of more than 3.02e-24, so the tool underpredicts this resin.
    source: banks2008
    where: Table VII (PMR-15 row, predicted column)
  - benchmark: thermo_oxidative_weight_loss
    label: Weight loss of neat resin in air at 316 degC
    value: 16.3
    unit: '%'
    scope: material
    conditions:
      product: PMR-15 neat resin, postcured
      exposure: 151 hr in air at 316 degC
    method: Value printed in NASA report table of neat PMR polyimide resins, footnote b
    status: ground
    note: This is a non-canonical benchmark name (thermo_oxidative_weight_loss). It has no entry in the canonical list.
    source: serafini1983
    where: Table II (PMR-15 row, weight loss column; footnote b)
  - benchmark: thermo_oxidative_weight_loss
    label: Weight loss of PMR-15 graphite composite in air at 316 degC
    value: 7.4
    unit: '%'
    scope: material
    conditions:
      product: PMR-15 unidirectional Celion 6000 graphite fibre composite
      exposure: 1512 hr in air at 316 degC
    method: Value printed in NASA report table of PMR polyimide/Celion 6000 composites, footnote c
    status: ground
    note: Non-canonical benchmark name (thermo_oxidative_weight_loss).
    source: serafini1983
    where: Table IV (PMR-15 row, weight loss column; footnote c)
  - benchmark: flexural_strength
    label: Flexural strength of PMR-15 graphite composite at 316 degC
    value: 896
    unit: MPa
    scope: material
    conditions:
      product: PMR-15 unidirectional Celion 6000 graphite fibre composite, normalized to 60 vol% fiber
      temperature: 316 degC (header reads as 316 degC; the scan is partly garbled, read as 316)
      postcure: 24 hr in air at 316 degC
    method: Value printed in NASA report table of PMR polyimide/Celion 6000 composites (footnote b, normalized to 60 vol% fiber)
    status: ground
    source: serafini1983
    where: Table IV (PMR-15 row, flexural strength column)
  - benchmark: flexural_modulus
    label: Flexural modulus of PMR-15 graphite composite at 316 degC
    value: 112
    unit: GPa
    scope: material
    conditions:
      product: PMR-15 unidirectional Celion 6000 graphite fibre composite, normalized to 60 vol% fiber
      temperature: 316 degC (header reads as 316 degC; the scan is partly garbled, read as 316)
      postcure: 24 hr in air at 316 degC
    method: Value printed in NASA report table of PMR polyimide/Celion 6000 composites (footnote b, normalized to 60 vol% fiber)
    status: ground
    source: serafini1983
    where: Table IV (PMR-15 row, flexural modulus column)
  - benchmark: interlaminar_shear_strength
    label: Interlaminar shear strength of PMR-15 graphite composite at 316 degC
    value: 50.7
    unit: MPa
    scope: material
    conditions:
      product: PMR-15 unidirectional Celion 6000 graphite fibre composite
      temperature: 316 degC (header reads as 316 degC; the scan is partly garbled, read as 316)
      postcure: 24 hr in air at 316 degC
    method: Value printed in NASA report table of PMR polyimide/Celion 6000 composites
    status: ground
    source: serafini1983
    where: Table IV (PMR-15 row, interlaminar shear strength column)
corrosion:
  - environment: Atomic oxygen in low Earth orbit
    headline: Atomic oxygen erodes PMR-15 at more than 3.02e-24 cm3 per atom, so exposed resin wears away.
    effect: On MISSE 2 (3.95 years on the ISS, fluence 8.43e21 atoms/cm2), the PMR-15 sample eroded through, so the printed erosion yield of more than 3.02e-24 cm3/atom is a lower bound. Its predicted value is 2.27e-24 cm3/atom, lower than the measurement.
    rating: severe
    conditions:
      flight: MISSE 2, PEC 2 tray 1, 3.95 yr, fluence 8.43e21 atoms/cm2
    source: banks2008
    where: Table I; Table VII; Section 2.1
  - environment: Air at 316 degC (thermo-oxidative ageing)
    headline: At 316 degC in air the neat resin lost 16.3 percent of its weight after 151 hours.
    effect: The neat PMR-15 resin lost 16.3 percent weight after 151 hours in air at 316 degC. A PMR-15 graphite composite lost 7.4 percent after 1512 hours in air at 316 degC. The authors compared the composite with its own PMR-NV variants, which are not PMR-15.
    rating: moderate
    conditions:
      neat_resin: 151 hr in air at 316 degC
      composite: 1512 hr in air at 316 degC, Celion 6000 graphite fibre
    source: serafini1983
    where: Table II (footnote b); Table IV (footnote c)
risks:
  hazards:
    - text: MDA, the aromatic diamine used to make PMR-15, is listed under GHS with H350 (may cause cancer), H341 (suspected of causing genetic defects), H317 (may cause an allergic skin reaction), H370 (causes damage to organs), H373 (may cause damage to organs after repeated exposure) and H411 (toxic to aquatic life with long lasting effects), signal word Danger. The cured resin is not classified by this source.
      ghs:
        - H317
        - H341
        - H350
        - H370
        - H373
        - H411
      source: wiki-mda
      where: Infobox (hazard statements and signal word)
    - text: NASA Glenn describes MDA as a mutagen and suspect carcinogen, and says that the health and safety issues it raises add to the manufacturing cost of PMR-15 even though the raw material itself is inexpensive.
      ghs: []
      source: johnston2007
      where: Abstract (page 1)
  failure_risks:
    - mode: Erosion by atomic oxygen
      trigger: Exposed PMR-15 in low Earth orbit (MISSE 2, 8.43e21 atoms/cm2 over 3.95 years)
      consequence: The sample eroded through, so a thin unprotected resin skin would not last.
      severity: high
      source: banks2008
      where: Table I; Section 2.1
    - mode: Blistering from residual endcap and volatiles
      trigger: Placing a cured neat resin suddenly into a 316 degC oven without a stepwise postcure
      consequence: Warping and blistering occurred in several instances; the report says residual unreacted norbornene endcaps can release volatiles at 316 degC.
      severity: moderate
      source: serafini1983
      where: Text on the postcure schedule (page 3)
    - mode: Loss of resin mass at the top use temperature
      trigger: Long exposure to air at 316 degC
      consequence: The neat resin loses 16.3 percent of its weight in 151 hours, and the composite loses 7.4 percent in 1512 hours.
      severity: moderate
      source: serafini1983
      where: Table II; Table IV
  side_effects:
    - text: Erosion products from the polymer are volatile and add to the gas around the spacecraft, which can matter for nearby optics.
      affects: Nearby optics and infrared instruments
      source: banks2008
      where: Section 2.1 context (MISSE 2 erosion data)
  handling:
    - text: Use the monomers in a controlled workplace. MDA is a suspected carcinogen, and the report says health and safety issues raise manufacturing costs.
      source: johnston2007
      where: Abstract (page 1)
    - text: Postcure in steps. Final cure is at 288 to 316 degC, and sudden exposure of a cured resin to 316 degC causes blisters.
      source: serafini1983
      where: Experimental and text sections on cure and postcure
uses:
  - application: propulsion-and-tanks
    device: QCSEE inner cowl for an experimental turbofan engine
    example: The QCSEE (Quiet Clean Short Haul Experimental Engine) inner cowl, a part of an experimental GE turbofan with a maximum diameter of about 90 cm, was made from PMR-15 composite and was undergoing ground-engine tests when the report was written.
    source: nasa1979
    where: Section 1, Applications (page 1)
  - application: propulsion-and-tanks
    device: Oil tank bracket and augmentor duct for F100 engines
    example: PMR-15 parts listed in the report include an oil tank bracket for the F100 engine (chopped graphite molding compound by Pratt and Whitney/TRW) and an augmentor duct for the F100 engine (Composites Horizons, Air Force).
    source: nasa1979
    where: Section 1, Applications, Table III
  - application: structures
    device: Shuttle orbiter aft body flap
    example: The report lists a shuttle orbiter aft body flap being developed by Boeing, about 2 m wide by 6.5 m long, as a PMR-15 structure.
    source: nasa1979
    where: Section 1, Applications (page 1)
documents:
  - title: 'NASA/TM-2008-215490: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit'
    type: report
    url: https://ntrs.nasa.gov/citations/20090011780
    year: 2008
  - title: NASA TM 79039, PMR-15 applications report (presented at a 1979 conference, Honolulu)
    type: report
    url: https://ntrs.nasa.gov/api/citations/19790003979/downloads/19790003979.pdf
    year: 1979
  - title: NASA technical report on PMR polyimide neat resins and Celion 6000 composites (NTRS 19830001848)
    type: report
    url: https://ntrs.nasa.gov/api/citations/19830001848/downloads/19830001848.pdf
    year: 1983
  - title: 'NASA Technical Memorandum 103768: Viscoelastic Properties of Addition-Cured Polyimide PMR-15 (NTRS 19910013064)'
    type: report
    url: https://ntrs.nasa.gov/api/citations/19910013064/downloads/19910013064.pdf
    year: 1991
  - title: Johnston and Kuczmarski, NASA Glenn, N-15 NMR study of imidization rates of diamines (NTRS 20070023557)
    type: report
    url: https://ntrs.nasa.gov/api/citations/20070023557/downloads/20070023557.pdf
    year: 2007
  - title: NASA report on PMR-15 monomers and MDA (NTRS 20020024447)
    type: report
    url: https://ntrs.nasa.gov/api/citations/20020024447/downloads/20020024447.pdf
    year: 2002
  - title: NASA report on PMR-15 composite fabrication and monomer chemistry (NTRS 19800020932)
    type: report
    url: https://ntrs.nasa.gov/api/citations/19800020932/downloads/19800020932.pdf
    year: 1980
  - title: Wikipedia, 4,4'-Methylenedianiline (infobox)
    type: report
    url: https://en.wikipedia.org/wiki/4,4%27-Methylenedianiline
    year: 2026
gaps:
  - 'Supply: no source was read for PMR-15 resin or its monomers (MDA, BTDE, NE) for producers, country shares, or critical-mineral lists, so there is no supply section.'
  - Moisture uptake, hygroscopic swelling and thermal cycling for PMR-15 were not found in pages read here.
  - Room-temperature mechanical properties (tensile, flexural, compressive) of neat PMR-15 were not entered; only the 316 degC composite values from Table IV were.
  - Total ionizing dose and UV tolerance for PMR-15 were not found in a source read in this run.
  - Current commercial prepreg suppliers and the state of AMB-21 or other MDA replacements were not checked in a fetched source; the search snippet on AMB-21 was not used.
  - The MISSE 2 erosion value is a lower bound (the sample eroded through), so no measured yield is available.
  - The monomer molar masses and CAS number for BTDE and NE were not read, so the recipe lists the stoichiometry only.
  - Two non-canonical benchmark names were used (thermo_oxidative_weight_loss); no canonical name exists for them in spores/property-canon.yaml.
  - The Table IV Tg and flexural columns in the NASA scan are partly garbled, so the test temperature was read from the header as 316 degC.
sources:
  banks2008:
    title: Atomic Oxygen Erosion Yield Predictive Tool for Spacecraft Polymers in Low Earth Orbit
    id: NASA/TM-2008-215490, NTRS 20090011780 (Banks, Backus and de Groh, December 2008)
    url: https://ntrs.nasa.gov/citations/20090011780
    year: 2008
    kind: report
    license: public domain (NASA)
  serafini1983:
    title: NASA report on PMR polyimide neat resins and Celion 6000 graphite composites (NTRS 19830001848)
    id: NTRS 19830001848 (1983)
    url: https://ntrs.nasa.gov/api/citations/19830001848/downloads/19830001848.pdf
    year: 1983
    kind: report
    license: NASA NTRS document, linked not reproduced
    note: Table II gives PMR-15 stoichiometry 2NE/3.087MDA/2.087BTDE. Table IV gives composite Tg 341, flexural strength 896 MPa, flexural modulus 112 GPa, interlaminar shear 50.7 MPa, weight loss 7.4 percent after 1512 hr at 316 degC. Text gives use up to 316 degC.
  nasa1991:
    title: Viscoelastic Properties of Addition-Cured Polyimide PMR-15, NASA Technical Memorandum 103768
    id: NTRS 19910013064 (1991)
    url: https://ntrs.nasa.gov/api/citations/19910013064/downloads/19910013064.pdf
    year: 1991
    kind: report
    license: NASA NTRS document, linked not reproduced
    note: Tg dry 362 degC and 349 degC with moisture, by dynamic mechanical analysis, within 5 degC of TMA.
  johnston2007:
    title: N-15 NMR spectroscopy as a method for comparing the rates of imidization of several diamines (Johnston and Kuczmarski, NASA Glenn)
    id: NTRS 20070023557 (2007)
    url: https://ntrs.nasa.gov/api/citations/20070023557/downloads/20070023557.pdf
    year: 2007
    kind: report
    license: NASA NTRS document, linked not reproduced
    note: PMR-15 is made from MDA, BTDE and NE monomers; oligomer molecular weight 1500 g/mole; MDA is a mutagen and suspect carcinogen.
  ntrs2002:
    title: NASA report on PMR-15 monomers and MDA replacement diamines (NTRS 20020024447)
    id: NTRS 20020024447 (2002)
    url: https://ntrs.nasa.gov/api/citations/20020024447/downloads/20020024447.pdf
    year: 2002
    kind: report
    license: NASA NTRS document, linked not reproduced
    note: States that MDA is a mutagen and suspected carcinogen used in PMR-15 polyimide.
  nasa1979:
    title: NASA Technical Memorandum 79039, PMR-15 applications (presented at a 1979 conference, Honolulu)
    id: NTRS 19790003979 (1979)
    url: https://ntrs.nasa.gov/api/citations/19790003979/downloads/19790003979.pdf
    year: 1979
    kind: report
    license: NASA NTRS document, linked not reproduced
    note: Lists QCSEE inner cowl, F100 engine oil tank bracket and augmentor duct, shuttle orbiter aft body flap, and max cure of 316 degC (600 degF).
  nasa1980:
    title: NASA report on PMR-15 composite fabrication, monomers and glass transition (NTRS 19800020932)
    id: NTRS 19800020932 (1980)
    url: https://ntrs.nasa.gov/api/citations/19800020932/downloads/19800020932.pdf
    year: 1980
    kind: report
    license: NASA NTRS document, linked not reproduced
    note: Describes the PMR-15 system as NE, BTDA-derived dimethyl ester and MDA, with formulated molecular weight 1500 (n = 2.087).
  wiki-mda:
    title: Wikipedia, 4,4'-Methylenedianiline (infobox)
    url: https://en.wikipedia.org/wiki/4,4%27-Methylenedianiline
    kind: web
    license: CC BY-SA (Wikipedia)
    note: CAS 101-77-9; molar mass 198.269 g/mol; hazard statements H317, H341, H350, H370, H373, H411; signal word Danger; IARC Group 2B.
license: CC-BY-4.0
updated: '2026-10-20'
review:
  status: draft
  method: assistant
  checked_values: 14
  unreachable: 0
  caveats: 4
  note: 'Written by an AI assistant on 2026-10-20. Values were read from text and tables of NASA NTRS PDFs downloaded in this run (MISSE 2 report, 1979, 1980, 1983, 1991 and 2002 reports, and the 2007 NMR paper) and from the Wikipedia MDA infobox. Caveats: the MISSE 2 erosion yield is a lower bound; the composite table header is partly garbled; the density differs between sources; supply is absent.'
story:
  recipe:
    line: PMR-15 is made by mixing three monomers in methanol, then curing them into a crosslinked polyimide. NASA's stoichiometry is 2 NE to 3.087 MDA to 2.087 BTDE, for a formulated molecular weight of 1500 g/mole. The NE endcap limits chain growth so the melt flows and volatiles can escape.
    parts:
      - name: MDA (4,4'-methylenedianiline)
        symbol: MDA
        share: 3.087 mol per formulation
        role: The diamine. It reacts with the anhydride ester to build the polyimide chain. Molar mass 198.269 g/mol (Wikipedia infobox).
      - name: BTDE (dialkyl ester of benzophenone tetracarboxylic acid)
        symbol: BTDE
        share: 2.087 mol per formulation
        role: The dianhydride component, supplied as the dialkyl ester in solution. It forms the imide rings on cure.
      - name: NE (monoalkyl ester of 5-norbornene-2,3-dicarboxylic acid)
        symbol: NE
        share: 2 mol per formulation
        role: The endcap. It limits the chain length so the oligomer stays low in melt viscosity, then crosslinks at high temperature.
  risk_groups:
    - title: For people
      level: 1
      verdict: The cured resin is not classified here; the MDA monomer is…
      lead: The main hazard is in making the resin, not in the finished part. MDA is a suspected carcinogen and mutagen.
      points:
        - label: MDA monomer
          line: MDA carries H350 (may cause cancer), H341 (suspected of causing genetic defects) and H370 (organ damage), signal word Danger, according to the Wikipedia infobox. NASA Glenn calls it a mutagen and suspect carcinogen.
        - label: Cost
          line: NASA Glenn says the monomer is inexpensive, but the health and safety handling adds to the manufacturing cost of PMR-15.
    - title: If it fails
      lead: These results come from flight exposure and laboratory ageing, not from failures of flight hardware.
      points:
        - label: Atomic oxygen
          line: On MISSE 2 the sample eroded through, so the erosion yield is more than 3.02e-24 cm3/atom. Exposed resin does not last in low Earth orbit.
        - label: Heat in air
          line: Neat resin lost 16.3 percent of its weight in 151 hours at 316 degC in air.
        - label: Sudden heat
          line: Cured parts placed suddenly into 316 degC blistered, because residual endcap volatiles escape.
  why: PMR-15 is the workhorse of high-temperature polyimide composites. It cures into a crosslinked resin that keeps useful flexural strength at 316 degC, which is why NASA and its partners used it for engine and airframe parts in the reports collected here.
  uses:
    - where: Use
      line: NASA's QCSEE experimental turbofan inner cowl, a PMR-15 composite about 90 cm across, was in ground-engine tests in 1979.
    - where: Use
      line: The report lists PMR-15 parts for the F100 engine, including an oil tank bracket and an augmentor duct.
    - where: Use
      line: A shuttle orbiter aft body flap, about 2 m wide by 6.5 m long, was in development as a PMR-15 structure.
  can_do:
    - label: Strength
      line: Hold a flexural strength of 896 MPa at 316 degC in a graphite composite, normalised to 60 vol% fiber.
    - label: Strength
      line: Keep a glass transition of 332 degC in the neat resin and 341 degC in the composite.
    - label: Strength
      line: Be used for structures up to 316 degC, with a stepwise postcure.
  compare: PMR-15 is a high-temperature thermoset, so its strength is kept at 316 degC by the crosslinked network, and its density (1.287 g/cm3) is typical of aromatic polyimides. Its erosion in low Earth orbit is high, so it needs a protective cover there. The table compares it with its two nearest benchmarks in the collection.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Glass transition
      benchmark: glass_transition_temperature
    - label: Atomic oxygen erosion
      benchmark: atomic_oxygen_erosion_yield
  handling:
    - 'Treat MDA as a carcinogen during resin making: control the workplace and limit exposure.'
    - Postcure in steps, up to 316 degC, so volatiles escape before the final heat.
    - Protect exposed resin in low Earth orbit, because it erodes.
  good_for:
    - Structural composites at 290 to 316 degC, such as engine ducts and cowls.
    - Parts that must hold flexural strength at 316 degC for many hours in air (7.4 percent composite weight loss after 1512 hr).
  watch_out:
    - MDA is a suspected carcinogen and mutagen, which raises manufacturing cost and handling needs.
    - Atomic oxygen erodes PMR-15 in orbit; the MISSE 2 sample eroded through.
    - Neat resin loses 16.3 percent of its weight in 151 hours at 316 degC in air.
  verdict: PMR-15 is the proven high-temperature composite resin in this collection. It keeps strength at 316 degC, but it needs careful handling in making and protection from atomic oxygen in orbit.