{
  "spore": "profile",
  "id": "im7-8552",
  "spore_version": "0.2",
  "family": "carbon-epoxy",
  "name": "Hexcel IM7/8552 carbon-epoxy prepreg",
  "abbreviation": "IM7/8552",
  "role": "unidirectional and woven aerospace structural prepreg",
  "category": "composites",
  "type": "carbon-fiber-reinforced",
  "summary": "IM7/8552 is a carbon-epoxy prepreg made from Hexcel IM7 carbon fibre and HexPly 8552, an amine-cured, toughened epoxy matrix. For the unidirectional prepreg, the Hexcel European datasheet gives a 0° tensile strength of 2724 MPa and a 0° tensile modulus of 164 GPa at 25 °C dry. The NCAMP qualification report gives a laminate glass transition of 406.43 °F dry and 321.41 °F wet by DMA, while the neat resin datasheet gives 200 °C dry and 154 °C wet; the two methods are not directly comparable.\n",
  "best_for": "Primary aerospace structures that need high 0° strength and stiffness: 2724 MPa tensile strength and 164 GPa tensile modulus at 25 °C dry for the unidirectional prepreg (Hexcel datasheet)",
  "weakest_at": "Hot-wet performance: the measured longitudinal tensile strength falls from 371.08 ksi at room temperature dry to 327.96 ksi at 250 °F wet (NCAMP lamina test), and the datasheet service envelope is 121 °C (250 °F)",
  "identity": {
    "formula": "Carbon fibre (IM7, 12K tow) reinforcement in an amine-cured, toughened epoxy matrix (HexPly 8552)",
    "designations": [],
    "source": "hexcel-eu-ds",
    "where": "Page 1 (description: amine cured, toughened epoxy supplied with unidirectional or woven carbon fibres); page 2 (IM7 filament count 12K)"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "structures"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "IM7 carbon fibre density",
      "value": 1.77,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "material": "IM7 carbon fibre as used in HexPly 8552 prepreg",
        "printed": "1.77 (0.064) g/cm3 (lb/in3)"
      },
      "method": "Value printed in the physical properties table of the unidirectional prepreg section",
      "status": "ground",
      "note": "The AS4 fibre in the same table prints 1.79 g/cm3 (0.065 lb/in3).",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Prepreg Properties (UD carbon prepregs), Physical Properties, Fibre Density row, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Resin density, HexPly 8552",
      "value": 1.3,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "material": "HexPly 8552 resin in the unidirectional prepreg",
        "printed": "1.30 (0.047) g/cm3 (lb/in3)"
      },
      "method": "Value printed in the physical properties table of the unidirectional prepreg section",
      "status": "ground",
      "note": "The typical neat resin data on page 4 print 1.301 g/cc, which agrees.",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Prepreg Properties (UD carbon prepregs), Physical Properties, Resin density row",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Nominal laminate density, unidirectional IM7/8552",
      "value": 1.57,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "cured unidirectional IM7/8552 laminate at nominal fibre volume",
        "printed": "1.57 (0.057) g/cm3 (lb/in3)"
      },
      "method": "Nominal value printed in the physical properties table",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Prepreg Properties (UD carbon prepregs), Nominal Laminate Density row, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "fibre_volume_fraction",
      "label": "Nominal fibre volume, unidirectional IM7 prepreg",
      "value": 57.7,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "basis": "nominal value for the cured UD IM7/8552 prepreg (8552/35%/134)"
      },
      "method": "Nominal value printed in the physical properties table",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Prepreg Properties (UD carbon prepregs), Nominal Fibre Volume row, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cured_ply_thickness",
      "label": "Nominal cured ply thickness, 8552/35%/134 prepreg",
      "value": 0.131,
      "bound": "exact",
      "unit": "mm",
      "scope": "material",
      "conditions": {
        "product": "IM7 unidirectional prepreg, 8552/35%/134",
        "printed": "0.131 (0.0052) mm (inch)"
      },
      "method": "Nominal value printed in the physical properties table",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Prepreg Properties (UD carbon prepregs), Nominal Cured Ply Thickness row, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Glass transition temperature, neat 8552 resin, dry",
      "value": 200,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "material": "neat (unreinforced) HexPly 8552 resin, cured",
        "condition": "dry",
        "printed": "200 °C (392 °F)"
      },
      "method": "Printed as typical neat resin data; the EU edition does not name the method (the US edition names RDS 7700 and prints 392 °F dry)",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 4, Typical Neat Resin Data, Tg dry",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Glass transition temperature, neat 8552 resin, wet",
      "value": 154,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "material": "neat (unreinforced) HexPly 8552 resin, cured",
        "condition": "wet",
        "printed": "154 °C (309 °F)"
      },
      "method": "Printed as typical neat resin data; the EU edition does not name the method (the US edition names RDS 7700 and prints 309 °F wet)",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 4, Typical Neat Resin Data, Tg wet",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Glass transition temperature, NCAMP qualification laminate, dry",
      "value": 406.43,
      "bound": "exact",
      "unit": "°F",
      "scope": "material",
      "conditions": {
        "laminate": "IM7 unidirectional 190 gsm, 35% RC, cured to NPS 81228 M cure cycle",
        "condition": "dry",
        "standard": "DMA per SACMA SRM 18-94"
      },
      "method": "Value printed in the lamina and laminate summary headers (DMA, SRM 18-94)",
      "status": "ground",
      "note": "Different specimen and method from the neat resin values above; the two sets are not interchangeable.",
      "source": "ornl-ncamp-2011",
      "where": "Section 2.1 (Lamina Level Test Summary), header, Tg(dry); the same value is repeated in Section 2.2",
      "source_detail": {
        "title": "Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report",
        "id": "NCAMP CAM-RP-2009-015 Rev A (NIAR, Wichita State University), April 22, 2011; FAA special project",
        "url": "https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf",
        "year": 2011,
        "kind": "report",
        "license": "NCAMP report hosted by ORNL (cited, not reproduced)"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "Glass transition temperature, NCAMP qualification laminate, wet",
      "value": 321.41,
      "bound": "exact",
      "unit": "°F",
      "scope": "material",
      "conditions": {
        "laminate": "IM7 unidirectional 190 gsm, 35% RC, cured to NPS 81228 M cure cycle",
        "condition": "wet",
        "standard": "DMA per SACMA SRM 18-94"
      },
      "method": "Value printed in the lamina and laminate summary headers (DMA, SRM 18-94)",
      "status": "ground",
      "note": "Different specimen and method from the neat resin values above; the two sets are not interchangeable.",
      "source": "ornl-ncamp-2011",
      "where": "Section 2.1 (Lamina Level Test Summary), header, Tg(wet); the same value is repeated in Section 2.2",
      "source_detail": {
        "title": "Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report",
        "id": "NCAMP CAM-RP-2009-015 Rev A (NIAR, Wichita State University), April 22, 2011; FAA special project",
        "url": "https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf",
        "year": 2011,
        "kind": "report",
        "license": "NCAMP report hosted by ORNL (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, neat 8552 resin",
      "value": 121,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "material": "neat HexPly 8552 resin, cured",
        "printed": "121 MPa (17.5 ksi)"
      },
      "method": "Printed as typical neat resin data; test temperature not printed",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 4, Typical Neat Resin Data, Tensile Strength",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Tensile modulus, neat 8552 resin",
      "value": 4670,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "material": "neat HexPly 8552 resin, cured",
        "printed": "4670 MPa (0.677 msi)"
      },
      "method": "Printed as typical neat resin data; test temperature not printed",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 4, Typical Neat Resin Data, Tensile Modulus",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "0° tensile strength at -55 °C, dry",
      "value": 2572,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "fibre_orientation": "0°",
        "form": "unidirectional IM7/8552 prepreg, cured",
        "temperature": "-55 °C (-67 °F)",
        "condition": "dry",
        "printed": "2572 (373) MPa (ksi)"
      },
      "method": "Value printed in the UD mechanical properties table, IM7 column",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Mechanical Properties, 0° Tensile Strength, -55 (-67) Dry, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "0° tensile strength at 25 °C, dry",
      "value": 2724,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "fibre_orientation": "0°",
        "form": "unidirectional IM7/8552 prepreg, cured",
        "temperature": "25 °C (77 °F)",
        "condition": "dry",
        "printed": "2724 (395) MPa (ksi)"
      },
      "method": "Value printed in the UD mechanical properties table, IM7 column",
      "status": "ground",
      "note": "The AS4 fibre in the same row prints 2207 MPa (320 ksi).",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Mechanical Properties, 0° Tensile Strength, 25 (77) Dry, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "0° tensile modulus at -55 °C, dry",
      "value": 163,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "fibre_orientation": "0°",
        "form": "unidirectional IM7/8552 prepreg, cured",
        "temperature": "-55 °C (-67 °F)",
        "condition": "dry",
        "printed": "163 (23.7) GPa (msi)"
      },
      "method": "Value printed in the UD mechanical properties table, IM7 column",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Mechanical Properties, 0° Tensile Modulus, -55 (-67) Dry, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "0° tensile modulus at 25 °C, dry",
      "value": 164,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "fibre_orientation": "0°",
        "form": "unidirectional IM7/8552 prepreg, cured",
        "temperature": "25 °C (77 °F)",
        "condition": "dry",
        "printed": "164 (23.8) GPa (msi)"
      },
      "method": "Value printed in the UD mechanical properties table, IM7 column",
      "status": "ground",
      "note": "The AS4 fibre in the same row prints 141 GPa (20.5 msi).",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Mechanical Properties, 0° Tensile Modulus, 25 (77) Dry, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "0° tensile elongation at 77 °F, dry",
      "value": 1.62,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "fibre_orientation": "0°",
        "form": "unidirectional IM7/8552 prepreg",
        "temperature": "77 °F (25 °C)",
        "condition": "dry"
      },
      "method": "Value printed in the mechanical properties table of the US edition, IM7 column",
      "status": "ground",
      "source": "hexcel-us-ds",
      "where": "Page 3, Mechanical Properties, 0° Tensile elongation, %, 77 Dry, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, US edition (Hexcel, copyright 2020)",
        "id": "Hexcel US product data sheet, file dated 2026-01 on hexcel.com",
        "url": "https://hexcel.com/wp-content/uploads/2026/01/HexPly_8552_us_DataSheet.pdf",
        "year": 2020,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "label": "Major Poisson's ratio in tension, dry",
      "value": 0.316,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "fibre_orientation": "0° (major Poisson's ratio, tension)",
        "temperature": "77 °F (25 °C)",
        "condition": "dry"
      },
      "method": "Value printed in the mechanical properties table of the US edition, IM7 column",
      "status": "ground",
      "note": "The NCAMP lamina test at room temperature dry also prints 0.316 for the longitudinal Poisson's ratio.",
      "source": "hexcel-us-ds",
      "where": "Page 3, Mechanical Properties, Major Poisson's Ratio, tension, 77 Dry, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, US edition (Hexcel, copyright 2020)",
        "id": "Hexcel US product data sheet, file dated 2026-01 on hexcel.com",
        "url": "https://hexcel.com/wp-content/uploads/2026/01/HexPly_8552_us_DataSheet.pdf",
        "year": 2020,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "90° tensile strength at 25 °C, dry",
      "value": 64,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "fibre_orientation": "90°",
        "form": "unidirectional IM7/8552 prepreg, cured",
        "temperature": "25 °C (77 °F)",
        "condition": "dry",
        "printed": "64 (9.3) MPa (ksi)"
      },
      "method": "Value printed in the UD mechanical properties table, IM7 column",
      "status": "ground",
      "note": "The AS4 fibre in the same row prints 81 MPa (11.7 ksi).",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Mechanical Properties, 90° Tensile Strength, 25 (77) Dry, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "90° tensile modulus at 25 °C, dry",
      "value": 12,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "fibre_orientation": "90°",
        "form": "unidirectional IM7/8552 prepreg, cured",
        "temperature": "25 °C (77 °F)",
        "condition": "dry",
        "printed": "12 (1.7) GPa (msi)"
      },
      "method": "Value printed in the UD mechanical properties table, IM7 column",
      "status": "ground",
      "note": "The AS4 fibre in the same row prints 10 GPa (1.39 msi).",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Mechanical Properties, 90° Tensile Modulus, 25 (77) Dry, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "compressive_strength_0deg",
      "label": "0° compression strength at 25 °C, dry",
      "value": 1690,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "fibre_orientation": "0°",
        "form": "unidirectional IM7/8552 prepreg, cured",
        "temperature": "25 °C (77 °F)",
        "condition": "dry",
        "printed": "1690 (245) MPa (ksi)"
      },
      "method": "Value printed in the UD mechanical properties table, IM7 column",
      "status": "ground",
      "note": "Not a canonical property name; the AS4 fibre in the same row prints 1531 MPa (222 ksi).",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Mechanical Properties, 0° Compression Strength, 25 (77) Dry, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "compressive_modulus_0deg",
      "label": "0° compression modulus at 25 °C, dry",
      "value": 150,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "fibre_orientation": "0°",
        "form": "unidirectional IM7/8552 prepreg, cured",
        "temperature": "25 °C (77 °F)",
        "condition": "dry",
        "printed": "150 (21.7) GPa (msi)"
      },
      "method": "Value printed in the UD mechanical properties table, IM7 column",
      "status": "ground",
      "note": "Not a canonical property name; the AS4 fibre in the same row prints 128 GPa (18.6 msi).",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Mechanical Properties, 0° Compression Modulus, 25 (77) Dry, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "interlaminar_shear_strength_short_beam",
      "label": "0° short-beam (interlaminar) shear strength at 25 °C, dry",
      "value": 137,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "fibre_orientation": "0°",
        "test": "short-beam shear",
        "temperature": "25 °C (77 °F)",
        "condition": "dry",
        "printed": "137 (19.9) MPa (ksi)"
      },
      "method": "Value printed in the UD mechanical properties table, IM7 column",
      "status": "ground",
      "note": "Not a canonical property name; the AS4 fibre in the same row prints 128 MPa (18.5 ksi).",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Mechanical Properties, 0° ILSS (Shortbeam shear), 25 (77) Dry, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "interlaminar_shear_strength_short_beam",
      "label": "0° short-beam (interlaminar) shear strength at 25 °C, wet",
      "value": 115,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "fibre_orientation": "0°",
        "test": "short-beam shear",
        "temperature": "25 °C (77 °F)",
        "condition": "wet",
        "printed": "115 (16.7) MPa (ksi)"
      },
      "method": "Value printed in the UD mechanical properties table, IM7 column; the datasheet labels this row as wet",
      "status": "ground",
      "note": "Dry value at the same temperature is 137 MPa (19.9 ksi).",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Mechanical Properties, 0° ILSS (Shortbeam shear), 25 (77) Wet, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "in_plane_shear_strength",
      "label": "In-plane shear strength at 25 °C, dry",
      "value": 120,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C (77 °F)",
        "condition": "dry",
        "printed": "120 (17.4) MPa (ksi)"
      },
      "method": "Value printed in the UD mechanical properties table, IM7 column",
      "status": "ground",
      "note": "Not a canonical property name; the AS4 fibre in the same row prints 114 MPa (16.6 ksi).",
      "source": "hexcel-eu-ds",
      "where": "Page 2, Mechanical Properties, In-plane Shear Strength, 25 (77) Dry, IM7 column",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Service environment the system was developed for",
      "value": 121,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "environments the system was developed to operate in",
        "printed": "121 °C (250 °F)"
      },
      "method": "Value printed in the product description; a development statement, not a qualification limit",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 1, Description",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cure_hold_temperature",
      "label": "Cure hold temperature, monolithic cure cycle",
      "value": 180,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "tolerance": "±5 °C",
        "hold": "120 minutes ±5 minutes",
        "pressure": "7 bar gauge autoclave pressure for monolithic components",
        "heating": "1 to 3 °C/min to hold temperature",
        "cooling": "2 to 5 °C/min"
      },
      "method": "Cure cycle printed in the curing conditions section (steps 6 to 8)",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 5, Curing Conditions, monolithic cure cycle, steps 6 to 8",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cure_stage1_temperature",
      "label": "Cure first hold temperature, monolithic cure cycle",
      "value": 110,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "tolerance": "±5 °C",
        "hold": "60 minutes ±5 minutes",
        "heating": "1 to 3 °C/min to first hold",
        "vacuum": "full vacuum (1 bar) applied at the start"
      },
      "method": "Cure cycle printed in the curing conditions section (steps 4 and 5)",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 5, Curing Conditions, monolithic cure cycle, steps 4 and 5",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cure_pressure",
      "label": "Autoclave pressure, monolithic components",
      "value": 7,
      "bound": "exact",
      "unit": "bar gauge",
      "scope": "material",
      "conditions": {
        "part": "monolithic components",
        "vacuum_reduction": "vacuum reduced to a safety value of 0.2 bar when autoclave pressure reaches approximately 1 bar gauge"
      },
      "method": "Cure cycle printed in the curing conditions section (step 2)",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 5, Curing Conditions, monolithic cure cycle, step 2",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cure_pressure",
      "label": "Autoclave pressure, honeycomb sandwich components",
      "value": 3.2,
      "bound": "exact",
      "unit": "bar gauge",
      "scope": "material",
      "conditions": {
        "part": "honeycomb sandwich components",
        "vacuum_reduction": "vacuum reduced to a safety value of 0.2 bar when autoclave pressure reaches approximately 1 bar gauge"
      },
      "method": "Cure cycle printed in the curing conditions section (step 2 of the honeycomb cycle)",
      "status": "ground",
      "source": "hexcel-eu-ds",
      "where": "Page 5, Curing Conditions, honeycomb sandwich cure cycle, step 2",
      "source_detail": {
        "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
        "id": "Hexcel FTA-072-MC23",
        "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "Hexcel product data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Longitudinal tensile strength, NCAMP lamina, room temperature dry (measured)",
      "value": 371.08,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "test_condition": "RTD: 70 ±10 °F, room temperature dry",
        "fibre": "IM7 unidirectional",
        "resin": "Hexcel 8552",
        "cure": "NPS 81228 M cure cycle",
        "lot_basis": "mean of lots 1 to 3"
      },
      "method": "Measured column of the lamina mechanical property summary, normalized values also reported",
      "status": "ground",
      "note": "Normalized to cured ply thickness 0.0072 inch, the same mean is 362.69 ksi.",
      "source": "ornl-ncamp-2011",
      "where": "Section 2.1 (Lamina Level Test Summary), Table 2-1, from LT row, RTD measured column",
      "source_detail": {
        "title": "Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report",
        "id": "NCAMP CAM-RP-2009-015 Rev A (NIAR, Wichita State University), April 22, 2011; FAA special project",
        "url": "https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf",
        "year": 2011,
        "kind": "report",
        "license": "NCAMP report hosted by ORNL (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Longitudinal tensile modulus, NCAMP lamina, room temperature dry (measured)",
      "value": 23.51,
      "bound": "exact",
      "unit": "Msi",
      "scope": "material",
      "conditions": {
        "test_condition": "RTD: 70 ±10 °F, room temperature dry",
        "fibre": "IM7 unidirectional",
        "resin": "Hexcel 8552",
        "cure": "NPS 81228 M cure cycle"
      },
      "method": "Measured column of the lamina mechanical property summary, normalized values also reported",
      "status": "ground",
      "note": "Normalized to cured ply thickness 0.0072 inch, the same mean is 22.99 Msi.",
      "source": "ornl-ncamp-2011",
      "where": "Section 2.1 (Lamina Level Test Summary), Table 2-1, E1 of LT row, RTD measured column",
      "source_detail": {
        "title": "Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report",
        "id": "NCAMP CAM-RP-2009-015 Rev A (NIAR, Wichita State University), April 22, 2011; FAA special project",
        "url": "https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf",
        "year": 2011,
        "kind": "report",
        "license": "NCAMP report hosted by ORNL (cited, not reproduced)"
      }
    },
    {
      "benchmark": "compressive_strength_0deg",
      "label": "Longitudinal compression strength, NCAMP lamina, room temperature dry (measured)",
      "value": 251.13,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "test_condition": "RTD: 70 ±10 °F, room temperature dry",
        "fibre": "IM7 unidirectional",
        "cure": "NPS 81228 M cure cycle",
        "test": "unnotched compression 0 (UNC0)"
      },
      "method": "Measured column of the lamina mechanical property summary, normalized values also reported",
      "status": "ground",
      "note": "Not a canonical property name; normalized to cured ply thickness 0.0072 inch, the same mean is 248.94 ksi.",
      "source": "ornl-ncamp-2011",
      "where": "Section 2.1 (Lamina Level Test Summary), Table 2-1, F1cu from UNC0 row, RTD measured column",
      "source_detail": {
        "title": "Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report",
        "id": "NCAMP CAM-RP-2009-015 Rev A (NIAR, Wichita State University), April 22, 2011; FAA special project",
        "url": "https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf",
        "year": 2011,
        "kind": "report",
        "license": "NCAMP report hosted by ORNL (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Longitudinal tensile strength, NCAMP lamina, hot-wet (measured)",
      "value": 327.96,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "test_condition": "ETW: 250 ±5 °F, wet (equilibrium moisture content)",
        "fibre": "IM7 unidirectional",
        "cure": "NPS 81228 M cure cycle"
      },
      "method": "Measured column of the lamina mechanical property summary, normalized values also reported",
      "status": "ground",
      "note": "Normalized to cured ply thickness 0.0072 inch, the same mean is 333.50 ksi.",
      "source": "ornl-ncamp-2011",
      "where": "Section 2.1 (Lamina Level Test Summary), Table 2-1, from LT row, ETW measured column",
      "source_detail": {
        "title": "Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report",
        "id": "NCAMP CAM-RP-2009-015 Rev A (NIAR, Wichita State University), April 22, 2011; FAA special project",
        "url": "https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf",
        "year": 2011,
        "kind": "report",
        "license": "NCAMP report hosted by ORNL (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Transverse tensile strength, NCAMP lamina, room temperature dry (measured)",
      "value": 9.29,
      "bound": "exact",
      "unit": "ksi",
      "scope": "material",
      "conditions": {
        "test_condition": "RTD: 70 ±10 °F, room temperature dry",
        "fibre": "IM7 unidirectional",
        "direction": "transverse (from TT)"
      },
      "method": "Measured column of the lamina mechanical property summary; transverse values are not normalized in the report",
      "status": "ground",
      "note": "Not a canonical property name for direction; the EU datasheet prints 64 MPa (9.3 ksi) at 25 °C dry for the 90° tensile strength.",
      "source": "ornl-ncamp-2011",
      "where": "Section 2.1 (Lamina Level Test Summary), Table 2-1, F2 tu (from TT) row, RTD measured column",
      "source_detail": {
        "title": "Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report",
        "id": "NCAMP CAM-RP-2009-015 Rev A (NIAR, Wichita State University), April 22, 2011; FAA special project",
        "url": "https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf",
        "year": 2011,
        "kind": "report",
        "license": "NCAMP report hosted by ORNL (cited, not reproduced)"
      }
    },
    {
      "benchmark": "fibre_volume_fraction",
      "label": "Fibre volume, NCAMP qualification material, method I",
      "value": 58.535,
      "bound": "exact",
      "unit": "%vol",
      "scope": "material",
      "conditions": {
        "method": "ASTM D3171 Method I (acid digestion)",
        "product": "IM7 unidirectional prepreg, 190 gsm and 35% RC"
      },
      "method": "Value printed in the normalization procedures section",
      "status": "ground",
      "note": "Method II gives 59.405 %vol; the report calls the two close enough.",
      "source": "ornl-ncamp-2011",
      "where": "Section 1.5.8 (Normalization Procedures), fiber volume paragraph",
      "source_detail": {
        "title": "Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report",
        "id": "NCAMP CAM-RP-2009-015 Rev A (NIAR, Wichita State University), April 22, 2011; FAA special project",
        "url": "https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf",
        "year": 2011,
        "kind": "report",
        "license": "NCAMP report hosted by ORNL (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cured_ply_thickness",
      "label": "Average cured ply thickness, NCAMP qualification material",
      "value": 0.0072,
      "bound": "exact",
      "unit": "inch",
      "scope": "material",
      "conditions": {
        "product": "IM7 unidirectional prepreg, 190 gsm and 35% RC",
        "basis": "average used as nominal for normalization"
      },
      "method": "Value printed in the normalization procedures section",
      "status": "ground",
      "note": "The datasheet 8552/35%/134 product prints 0.131 mm (0.0052 inch); the two products differ in areal weight.",
      "source": "ornl-ncamp-2011",
      "where": "Section 1.5.8 (Normalization Procedures), fiber volume paragraph",
      "source_detail": {
        "title": "Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report",
        "id": "NCAMP CAM-RP-2009-015 Rev A (NIAR, Wichita State University), April 22, 2011; FAA special project",
        "url": "https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf",
        "year": 2011,
        "kind": "report",
        "license": "NCAMP report hosted by ORNL (cited, not reproduced)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Hot and wet: 250 °F wet to equilibrium moisture content (NCAMP lamina test)",
      "headline": "Hot-wet conditioning lowers the measured longitudinal tensile strength from 371.08 ksi to 327.96 ksi.",
      "effect": "The qualification test reads the same lamina at room temperature dry and at 250 °F wet. Both are measured values; the normalized means are 362.69 ksi and 333.50 ksi.",
      "rating": "moderate",
      "conditions": {
        "dry": "RTD: 70 ±10 °F, room temperature dry",
        "wet": "ETW: 250 ±5 °F, wet (equilibrium moisture content)"
      },
      "source": "ornl-ncamp-2011",
      "where": "Section 2.1 (Lamina Level Test Summary), Table 2-1, from LT row"
    },
    {
      "environment": "Wet conditioning of the neat resin (datasheet)",
      "headline": "The neat resin glass transition falls from 200 °C dry to 154 °C wet.",
      "effect": "Typical neat resin data from the EU datasheet. The US edition prints 392 °F dry and 309 °F wet under RDS 7700, so the two editions agree on the same resin.",
      "rating": "moderate",
      "conditions": {
        "basis": "typical neat resin data; method not named in the EU edition"
      },
      "source": "hexcel-eu-ds",
      "where": "Page 4, Typical Neat Resin Data, Tg dry and Tg wet"
    },
    {
      "environment": "Wet conditioning of the qualification laminate, DMA",
      "headline": "The laminate glass transition falls from 406.43 °F dry to 321.41 °F wet.",
      "effect": "Measured by DMA under SACMA SRM 18-94 on the NCAMP qualification laminate. The neat resin values above come from a different specimen and are not interchangeable with these.",
      "rating": "moderate",
      "conditions": {
        "standard": "DMA per SACMA SRM 18-94",
        "laminate": "IM7 unidirectional 190 gsm, 35% RC"
      },
      "source": "ornl-ncamp-2011",
      "where": "Section 2.1 (Lamina Level Test Summary), header, Tg(dry) and Tg(wet)"
    },
    {
      "environment": "Wet short-beam shear at 25 °C",
      "headline": "Wet short-beam shear at 25 °C is 115 MPa, against 137 MPa dry.",
      "effect": "Both values are printed in the IM7 column at 25 °C, for the dry and wet condition rows of the datasheet's mechanical table.",
      "rating": "low",
      "conditions": {
        "temperature": "25 °C (77 °F)",
        "test": "0° short-beam shear"
      },
      "source": "hexcel-eu-ds",
      "where": "Page 2, Mechanical Properties, 0° ILSS (Shortbeam shear), 25 (77) Dry and Wet, IM7 column"
    },
    {
      "environment": "Atomic oxygen and erosion in low Earth orbit, carbon fibre composites (general)",
      "headline": "A NASA LDEF abstract reports about one ply of carbon fibre composite eroded in 70 months in low Earth orbit.",
      "effect": "The abstract covers carbon fibre composites generally, not IM7/8552, and gives no erosion yield. It says matrix erosion was more evident for a polysulfone matrix than for epoxy matrices.",
      "rating": "unknown",
      "conditions": {
        "exposure": "70 months, LDEF SAMPLE experiment",
        "material": "carbon fibre composites (general; resin not named for the eroded ply)"
      },
      "source": "nasa-ldes-ntrs",
      "where": "Abstract"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "The datasheet says the usual precautions for uncured synthetic resins and fine fibrous materials should be observed, and that a safety data sheet is available. The SDS was not retrieved, so no GHS classification is given here.",
        "ghs": [],
        "source": "hexcel-eu-ds",
        "where": "Page 6, Precautions for Use"
      },
      {
        "text": "Acrylonitrile, the monomer of the PAN precursor, is the raw material of this fibre and is not the cured composite. PubChem reports the aggregated ECHA C&L notifications with the signal word Danger and hazard statements H225, H301, H311, H315, H317, H318, H331, H335, H350 and H411, including H350: May cause cancer.",
        "ghs": [],
        "source": "pubchem-acrylonitrile",
        "where": "PubChem CID 7855, Safety and Hazards, GHS Classification (aggregated ECHA C&L Inventory notifications)"
      }
    ],
    "failure_risks": [
      {
        "mode": "Hot-wet strength loss",
        "trigger": "Conditioning at 250 °F wet to equilibrium moisture content",
        "consequence": "Longitudinal tensile strength measured 327.96 ksi, against 371.08 ksi at room temperature dry (NCAMP lamina test).",
        "severity": "moderate",
        "source": "ornl-ncamp-2011",
        "where": "Section 2.1, Table 2-1, ETW and RTD measured columns"
      },
      {
        "mode": "Use above the datasheet service envelope",
        "trigger": "Operation above 121 °C (250 °F)",
        "consequence": "The datasheet says the system was developed for environments up to 121 °C (250 °F). It gives no performance statement above that temperature.",
        "severity": "moderate",
        "source": "hexcel-eu-ds",
        "where": "Page 1, Description"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "Store the prepreg frozen at -18 °C in a sealed moisture-proof bag. Shelf life is 12 months at -18 °C from date of manufacture (maximum).",
        "source": "hexcel-eu-ds",
        "where": "Page 6, Storage Life"
      },
      {
        "text": "Tack life is 10 days at 23 °C (73 °F). Out life, the time between removal from the freezer and cure, is 30 days at 23 °C.",
        "source": "hexcel-eu-ds",
        "where": "Page 6, Storage Life"
      },
      {
        "text": "Use clean disposable inert gloves to protect the operator and avoid contaminating the material and components.",
        "source": "hexcel-eu-ds",
        "where": "Page 6, Precautions for Use"
      }
    ],
    "mitigations": [
      {
        "text": "Performance testing should accompany alternative cure cycles to ensure suitability for the particular application.",
        "source": "hexcel-eu-ds",
        "where": "Page 5, Curing Conditions, note"
      }
    ]
  },
  "uses": [
    {
      "application": "structures",
      "device": "Primary aerospace structures (unidirectional and woven prepreg)",
      "example": "Hexcel describes HexPly 8552 as a high performance tough epoxy matrix for use in primary aerospace structures.",
      "source": "hexcel-eu-ds",
      "where": "Page 1, Description"
    },
    {
      "application": "structures",
      "device": "Honeycomb sandwich components",
      "example": "The datasheet gives a separate cure cycle for honeycomb sandwich components, at 3.2 bar gauge autoclave pressure against 7 bar gauge for monolithic parts.",
      "source": "hexcel-eu-ds",
      "where": "Page 5, Curing Conditions, honeycomb sandwich cure cycle"
    },
    {
      "application": "structures",
      "device": "Space launcher and space and defence aircraft structures (typical uses)",
      "example": "The US edition lists space launchers and space and defence aircraft structures among typical uses of HexPly 8552.",
      "source": "hexcel-us-ds",
      "where": "Page 1, typical uses list, Space and Defense column"
    }
  ],
  "supply": [
    {
      "subject": "Carbon fibre precursor (polyacrylonitrile, PAN)",
      "producers": [],
      "critical_lists": [],
      "substitutes": [],
      "source": "pmc-melt-spinnable-pan",
      "where": "Section 1, Introduction: 'acrylonitrile (AN) copolymers are the most frequently used precursors for the production of carbon fibers'. The review gives no country shares."
    },
    {
      "subject": "Acrylonitrile (PAN monomer)",
      "producers": [],
      "critical_lists": [],
      "substitutes": [],
      "source": "hexcel-10k-fy2024",
      "where": "Item 1, Business, Raw Materials and Production Activities: 'The primary raw material for PAN is acrylonitrile.' No producer shares or critical-mineral listing were read for acrylonitrile."
    },
    {
      "subject": "Carbon fibre (Hexcel PAN-based fibre)",
      "producers": [],
      "critical_lists": [],
      "substitutes": [],
      "source": "hexcel-10k-fy2024",
      "where": "Item 1, Business, Raw Materials and Production Activities: 'We manufacture high performance carbon fiber from polyacrylonitrile precursor'; a new Decatur, AL line 'is expected to be qualified to produce carbon fiber for aerospace markets in 2028'. Item 1, Patents and Know-How: Salt Lake City carbon fibre and prepreg operations. No country shares are printed."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "HexPly 8552 Product Data Sheet, EU edition",
      "type": "datasheet",
      "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
      "year": 2023
    },
    {
      "title": "HexPly 8552 Product Data Sheet, US edition",
      "type": "datasheet",
      "url": "https://hexcel.com/wp-content/uploads/2026/01/HexPly_8552_us_DataSheet.pdf",
      "year": 2020
    },
    {
      "title": "Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report (NCAMP CAM-RP-2009-015 Rev A)",
      "type": "report",
      "url": "https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf",
      "year": 2011
    },
    {
      "title": "LDEF SAMPLE experiment abstract (NASA NTRS 19940007012)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/19940007012"
    },
    {
      "title": "Hexcel Corporation Form 10-K for fiscal year 2024 (SEC filing)",
      "type": "report",
      "url": "https://www.sec.gov/Archives/edgar/data/717605/000095017025014412/hxl-20241231.htm",
      "year": 2025
    },
    {
      "title": "Acrylonitrile, PubChem CID 7855 (GHS classification)",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/7855/JSON?heading=GHS+Classification"
    },
    {
      "title": "Melt-Spinnable Polyacrylonitrile, An Alternative Carbon Fiber Precursor (Polymers, 2022)",
      "type": "paper",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC9738362/",
      "year": 2022
    }
  ],
  "gaps": [
    "Supply: producer country shares, critical-mineral listings and manufacturing shares for IM7 fibre and HexPly 8552 were not found in the sources read. The Hexcel 10-K names the PAN precursor, acrylonitrile and the Decatur and Salt Lake City sites without shares, and the PMC review gives no percentage. The Hexcel contact page linked from the datasheet was not read.",
    "Moisture uptake: no equilibrium moisture content percentage was found in the sources read. The NCAMP report describes the wet condition but prints no percentage.",
    "Coefficient of thermal expansion: no value for IM7/8552 was found in the sources read.",
    "Space environment: no atomic oxygen, UV, thermal-vacuum or flight result for IM7/8552 was found. The only space-related source is a NASA LDEF abstract that covers carbon fibre composites generally.",
    "Safety data sheet: the HexPly 8552 SDS was not found by search, so hazard data for the cured or uncured prepreg are limited to a datasheet statement. The only GHS data are for acrylonitrile, the PAN monomer, from PubChem; they do not describe the composite.",
    "NMS 128 Rev D material specification: the Wichita page returned no readable text to WebFetch, so specification limits were not used. The NMS 128/2 number printed in the NCAMP report was not added as a designation because NMS is not in the designation system list.",
    "Canonical names: compressive strength, compressive modulus, short-beam shear, in-plane shear, fibre volume, cured ply thickness, cure temperature and cure pressure are not in property-canon.yaml. Short snake_case names were used; please review.",
    "Two datasheet editions: the EU edition (2023) and the US edition (2020) are both cited, each for the values it prints. Metric values are taken from the EU edition; elongation and Poisson's ratio come from the US edition, which prints no metric elongation.",
    "Two products: the NCAMP report covers IM7/8552 at 190 gsm and 35% RC, and the datasheet covers 8552/35%/134. The two differ in areal weight and are not interchangeable.",
    "Fibre volume: the NCAMP report prints 58.535 %vol (Method I) and 59.405 %vol (Method II); the datasheet nominal is 57.70 %. All three are kept with their sources.",
    "Hot-wet and long-term ageing: no data beyond 250 °F wet or beyond the single NCAMP condition were found. The datasheet gives wet ILSS only at 25 °C.",
    "Laminate-level results (open hole, filled hole, bearing, compression after impact) were not transcribed; the NCAMP report uses several layups and each would need its layup named.",
    "The NCAMP values were read from pdftotext table layout, not from the page image; the ETW and RTD column positions were checked against the column headers, but a visual check was not done."
  ],
  "story": {
    "why": "HexPly 8552 IM7 is a carbon-epoxy prepreg for primary aerospace structures. It pairs IM7 carbon fibre with a toughened epoxy matrix and cures at 180 °C under pressure. The datasheet says the matrix gives good impact resistance and damage tolerance. An NCAMP qualification report prepared for an FAA special project records lamina test data for this material, so its strength and stiffness values come with a test record.",
    "uses": [
      {
        "where": "Primary aerospace structures",
        "line": "Hexcel describes HexPly 8552 as a high performance tough epoxy matrix for use in primary aerospace structures. The US edition also lists space launchers and space and defence aircraft structures among typical uses."
      },
      {
        "where": "Honeycomb sandwich components",
        "line": "The datasheet gives a separate cure cycle for honeycomb sandwich components. It uses 3.2 bar gauge autoclave pressure, against 7 bar gauge for monolithic parts."
      }
    ],
    "can_do": [
      {
        "label": "Stiffness",
        "line": "The 0° tensile modulus of the unidirectional IM7 prepreg is 164 GPa at 25 °C dry, per the Hexcel EU datasheet. The AS4 version of the same resin prints 141 GPa.",
        "benchmark": "elastic_modulus",
        "scope": "material",
        "value": "164 GPa"
      },
      {
        "label": "Strength",
        "line": "The 0° tensile strength is 2724 MPa (395 ksi) at 25 °C dry, per the Hexcel EU datasheet.",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material",
        "value": "2724 MPa"
      },
      {
        "label": "Heat tolerance",
        "line": "The neat resin glass transition is 200 °C dry and 154 °C wet, per the Hexcel EU datasheet. The NCAMP laminate reads 406.43 °F dry and 321.41 °F wet by DMA, which is a different specimen and method.",
        "benchmark": "glass_transition_temperature",
        "scope": "material",
        "value": "200 °C dry, 154 °C wet"
      },
      {
        "label": "Service environment",
        "line": "The datasheet says the system was developed to operate in environments up to 121 °C (250 °F).",
        "benchmark": "max_service_temp",
        "scope": "material",
        "value": "121 °C (250 °F)"
      }
    ],
    "compare": "Against AS4 carbon fibre in the same HexPly 8552 matrix, IM7 gives a higher 0° tensile strength (2724 MPa against 2207 MPa at 25 °C dry) and a higher 0° tensile modulus (164 GPa against 141 GPa), per the same Hexcel EU datasheet table. The IM7 fibre is slightly less dense, at 1.77 g/cm3 against 1.79 g/cm3 for AS4. The short-beam shear strength is slightly higher for IM7 (137 MPa against 128 MPa dry at 25 °C). The table below compares the tensile strength, tensile modulus and density of IM7/8552 with the other properties in this record that a like-for-like comparison can use.",
    "compare_rows": [
      {
        "label": "0° tensile strength, 25 °C dry",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material"
      },
      {
        "label": "0° tensile modulus, 25 °C dry",
        "benchmark": "elastic_modulus",
        "scope": "material"
      },
      {
        "label": "Fibre density",
        "benchmark": "density",
        "scope": "material"
      }
    ],
    "handling": [
      "Store the prepreg frozen at -18 °C, sealed in a moisture-proof bag. Shelf life is 12 months from manufacture.",
      "Tack life is 10 days at 23 °C. Out life is 30 days at 23 °C between removal from the freezer and cure.",
      "Use clean disposable inert gloves, as the datasheet advises.",
      "Cure with the printed cycle: 7 bar gauge for monolithic parts and 3.2 bar gauge for honeycomb sandwich. Performance test any alternative cure cycle."
    ],
    "good_for": [
      "Primary aerospace structures that need high 0° strength and stiffness. The unidirectional prepreg gives 2724 MPa and 164 GPa at 25 °C dry.",
      "Parts that need a test record. The NCAMP report gives lamina data with normalization to cured ply thickness."
    ],
    "watch_out": [
      "Hot-wet strength loss. Longitudinal tensile strength falls from 371.08 ksi at room temperature dry to 327.96 ksi at 250 °F wet.",
      "Service envelope of 121 °C (250 °F). The datasheet does not give a higher operating limit.",
      "Glass transition values differ by method. The neat resin reads 200 °C dry and 154 °C wet; the laminate reads 406.43 °F dry and 321.41 °F wet.",
      "Space exposure. No IM7/8552 atomic oxygen, UV or thermal-vacuum result was found; the one NASA abstract covers carbon fibre composites generally."
    ],
    "verdict": "IM7/8552 is a well-documented aerospace prepreg: the datasheets and the NCAMP report give its 0° strength and stiffness and its hot-wet values. Its hot-wet strength and the 121 °C (250 °F) service envelope should be checked against the application.",
    "recipe": {
      "line": "HexPly 8552 is an amine-cured, toughened epoxy matrix supplied with carbon fibre. The unidirectional IM7 prepreg uses IM7 carbon fibre in a 12K tow at a nominal fibre volume of 57.70 %, with the rest of the laminate volume taken by the resin. Carbon fibre is made from a precursor polymer such as polyacrylonitrile (PAN), spun into filaments and carbonized (Wikipedia). The composite is cured in an autoclave under vacuum and pressure, following the cure cycle in the properties.",
      "parts": [
        {
          "name": "IM7 carbon fibre",
          "role": "Carries most of the load along the fibre direction. The datasheet describes good translation of fibre properties into the laminate."
        },
        {
          "name": "HexPly 8552 epoxy matrix",
          "role": "Amine-cured, toughened epoxy that binds the fibres, transfers load between them and sets the controlled flow and service envelope described in the datasheet."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The Hexcel datasheet points to a separate safety data sheet for this product, which was not retrieved. Hazard information here is limited to the datasheet precautions.",
        "points": [
          {
            "label": "Uncured prepreg",
            "line": "The datasheet says the usual precautions for uncured synthetic resins and fine fibrous materials apply, and recommends clean disposable inert gloves."
          },
          {
            "label": "Cured composite",
            "line": "The sources read give no toxicology or dust data for the cured composite. That gap is listed under gaps."
          }
        ],
        "level": 0,
        "verdict": "No GHS hazard classification found in the sources read"
      },
      {
        "title": "Hot and wet",
        "lead": "Moisture and heat lower the glass transition and the strength measured in the qualification tests.",
        "points": [
          {
            "label": "Strength",
            "line": "Longitudinal tensile strength fell from 371.08 ksi at room temperature dry to 327.96 ksi at 250 °F wet, measured in NCAMP lamina tests."
          },
          {
            "label": "Short-beam shear",
            "line": "The datasheet prints 137 MPa dry and 115 MPa wet at 25 °C."
          },
          {
            "label": "Glass transition",
            "line": "The laminate glass transition is 406.43 °F dry and 321.41 °F wet by DMA. The neat resin is 200 °C dry and 154 °C wet in the datasheet. The two sets use different specimens and are not directly comparable."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Freezer storage",
            "line": "The prepreg is stored frozen at -18 °C, with a maximum shelf life of 12 months from manufacture, in a sealed moisture-proof bag."
          },
          {
            "label": "Working time",
            "line": "Tack life is 10 days at 23 °C. Out life, the time between removal from the freezer and cure, is 30 days at 23 °C."
          }
        ]
      }
    ]
  },
  "updated": "2026-11-01",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 36,
    "unreachable": 0,
    "caveats": 0,
    "note": "Values read in this run from the text of the two Hexcel datasheets and the NCAMP report (pdftotext for PDFs); not re-read from page images. Supply and feedstock rows and the acrylonitrile hazard entry were read in this run from the Hexcel FY2024 10-K, the PubChem acrylonitrile record and a 2022 Polymers review."
  },
  "sources": {
    "hexcel-eu-ds": {
      "title": "HexPly 8552 Product Data Sheet, EU edition (Hexcel, copyright 2023)",
      "id": "Hexcel FTA-072-MC23",
      "url": "https://www.hexcel.com/wp-content/uploads/2025/12/HexPly_8552_eu_DataSheet1.pdf",
      "year": 2023,
      "kind": "datasheet",
      "license": "Hexcel product data sheet (cited, not reproduced)"
    },
    "hexcel-us-ds": {
      "title": "HexPly 8552 Product Data Sheet, US edition (Hexcel, copyright 2020)",
      "id": "Hexcel US product data sheet, file dated 2026-01 on hexcel.com",
      "url": "https://hexcel.com/wp-content/uploads/2026/01/HexPly_8552_us_DataSheet.pdf",
      "year": 2020,
      "kind": "datasheet",
      "license": "Hexcel product data sheet (cited, not reproduced)"
    },
    "ornl-ncamp-2011": {
      "title": "Hexcel 8552 IM7 Unidirectional Prepreg 190 gsm and 35% RC: Qualification Material Property Data Report",
      "id": "NCAMP CAM-RP-2009-015 Rev A (NIAR, Wichita State University), April 22, 2011; FAA special project",
      "url": "https://thyme.ornl.gov/CFCrush/materials/uou/CAM-RP-2009-015_Rev_A_April_22_2011_Hexcel_8552_IM7_Uni_Data_Report.pdf",
      "year": 2011,
      "kind": "report",
      "license": "NCAMP report hosted by ORNL (cited, not reproduced)"
    },
    "wiki-cfrp": {
      "title": "Carbon fiber reinforced polymer (Wikipedia; used for composition and history only)",
      "id": "Wikipedia, accessed 2026-11-01",
      "url": "https://en.wikipedia.org/wiki/Carbon_fiber_reinforced_polymer",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0"
    },
    "nasa-ldes-ntrs": {
      "title": "LDEF SAMPLE experiment: carbon fibre composite erosion in low Earth orbit (NASA NTRS abstract)",
      "id": "NTRS 19940007012",
      "url": "https://ntrs.nasa.gov/citations/19940007012",
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "hexcel-10k-fy2024": {
      "title": "Hexcel Corporation Form 10-K for fiscal year 2024 (SEC filing)",
      "id": "SEC EDGAR filing for CIK 717605, accession 0000950170-25-014412",
      "url": "https://www.sec.gov/Archives/edgar/data/717605/000095017025014412/hxl-20241231.htm",
      "year": 2025,
      "kind": "report",
      "license": "public SEC filing"
    },
    "pubchem-acrylonitrile": {
      "title": "Acrylonitrile, PubChem CID 7855: GHS classification (aggregated ECHA C&L Inventory notifications)",
      "id": "PubChem CID 7855",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/7855/JSON?heading=GHS+Classification",
      "kind": "database",
      "license": "PubChem public database (NCBI)"
    },
    "pmc-melt-spinnable-pan": {
      "title": "Melt-Spinnable Polyacrylonitrile: An Alternative Carbon Fiber Precursor (Polymers, 2022)",
      "id": "PMC9738362",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC9738362/",
      "year": 2022,
      "kind": "paper",
      "license": "open access (PMC)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/im7-8552/"
}