{
  "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.\n",
  "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",
    "designations": [],
    "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,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "density",
      "label": "Density of PMR-15 (MISSE 2 reference)",
      "value": 1.3232,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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)"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Glass transition temperature, neat resin",
      "value": 332,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Glass transition temperature, dry film by dynamic mechanical analysis",
      "value": 362,
      "bound": "exact",
      "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",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Glass transition temperature, resin with absorbed moisture",
      "value": 349,
      "bound": "exact",
      "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",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Glass transition temperature, PMR-15 graphite composite",
      "value": 341,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Highest structural use temperature stated by NASA",
      "value": 316,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "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",
      "source_detail": {
        "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)"
      }
    },
    {
      "benchmark": "atomic_oxygen_erosion_yield",
      "label": "Atomic oxygen erosion yield, predicted by the NASA tool",
      "value": 2.27e-24,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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)"
      }
    },
    {
      "benchmark": "thermo_oxidative_weight_loss",
      "label": "Weight loss of neat resin in air at 316 degC",
      "value": 16.3,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "thermo_oxidative_weight_loss",
      "label": "Weight loss of PMR-15 graphite composite in air at 316 degC",
      "value": 7.4,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Flexural strength of PMR-15 graphite composite at 316 degC",
      "value": 896,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "flexural_modulus",
      "label": "Flexural modulus of PMR-15 graphite composite at 316 degC",
      "value": 112,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    },
    {
      "benchmark": "interlaminar_shear_strength",
      "label": "Interlaminar shear strength of PMR-15 graphite composite at 316 degC",
      "value": 50.7,
      "bound": "exact",
      "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)",
      "source_detail": {
        "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"
      }
    }
  ],
  "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"
      }
    ],
    "mitigations": []
  },
  "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)"
    }
  ],
  "supply": [],
  "media": [],
  "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."
  ],
  "story": {
    "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.",
        "scope": "material"
      },
      {
        "label": "Strength",
        "line": "Keep a glass transition of 332 degC in the neat resin and 341 degC in the composite.",
        "scope": "material"
      },
      {
        "label": "Strength",
        "line": "Be used for structures up to 316 degC, with a stepwise postcure.",
        "scope": "material"
      }
    ],
    "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",
        "scope": "material"
      },
      {
        "label": "Glass transition",
        "benchmark": "glass_transition_temperature",
        "scope": "material"
      },
      {
        "label": "Atomic oxygen erosion",
        "benchmark": "atomic_oxygen_erosion_yield",
        "scope": "material"
      }
    ],
    "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.",
    "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",
          "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",
          "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",
          "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",
        "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."
          }
        ],
        "level": 1,
        "verdict": "The cured resin is not classified here; the MDA monomer is…"
      },
      {
        "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."
          }
        ]
      }
    ]
  },
  "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."
  },
  "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"
    },
    "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"
    },
    "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"
    },
    "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"
    },
    "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"
    },
    "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"
    },
    "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)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/pi-pmr-15/"
}