{
  "spore": "profile",
  "id": "borated-polyethylene",
  "spore_version": "0.2",
  "family": "polyolefins",
  "name": "Borated polyethylene",
  "abbreviation": "BPE",
  "role": "neutron shield",
  "category": "shielding",
  "type": "hydrogen-rich-polymers",
  "summary": "Borated polyethylene is polyethylene loaded with boron, at 5 % boron by weight in the grades read, for neutron shielding. JCS Nuclear Solutions' JCPE5 (5 % boron, HMW grade) has a density of 1.04 g/cm3 (ISO 1183-1) and a melting temperature of 135 °C (ISO 11357-1/-3). MarShield's borated polyethylene is printed as 1.01 g/cc (ASTM D792) with a melting point of 128 °C (ASTM D3418), so the two datasheets differ. In a preliminary 2009 NASA proton test, boron-polyethylene at 5.35 g/cm2 gave 2.10 µGy per spill, against 2.11 µGy per spill for neat HDPE at 5.52 g/cm2, so no clear boron benefit showed at those thicknesses.\n",
  "best_for": "Neutron shielding where the temperature stays low, such as vault doors, containers and nuclear shields (5 % boron grade, density 1.04 g/cm3 per JCPE5)",
  "weakest_at": "Heat under load: heat deflection at 1.8 MPa is 45 °C (JCPE5) and 46.7 °C (MarShield), and continuous service is rated to 80 °C in air",
  "identity": {
    "formula": "(C2H4)n polyethylene with a boron filler, 5 % boron by weight in the grades read",
    "designations": [],
    "source": "wikipedia-polyethylene",
    "where": "Introduction and infobox, chemical formula (C2H4)n; boron content from the MarShield data sheet first page and the JCPE5 page"
  },
  "tags": {
    "environments": [],
    "stresses": [
      "total-radiation-dose",
      "extreme-cold",
      "extreme-heat"
    ],
    "applications": [
      "radiation-shielding"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, JCPE5 5 % borated polyethylene",
      "value": 1.04,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "JCPE5, 5 % boron loaded, HMW grade",
        "standard": "ISO 1183-1 as printed"
      },
      "method": "Typical value printed on the manufacturer product page",
      "status": "ground",
      "source": "jc-jcpe5",
      "where": "Specifications table, Density row",
      "source_detail": {
        "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page, Specifications table",
        "id": "Product page, Specifications table",
        "url": "https://johncaunt.com/products/jcpe5/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting temperature, JCPE5",
      "value": 135,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "JCPE5",
        "test": "DSC, 10 °C (50 °F) per minute, ISO 11357-1/-3 as printed"
      },
      "method": "Typical value printed on the manufacturer product page",
      "status": "ground",
      "source": "jc-jcpe5",
      "where": "Thermal Properties table, Melting temperature row",
      "source_detail": {
        "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page, Specifications table",
        "id": "Product page, Specifications table",
        "url": "https://johncaunt.com/products/jcpe5/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "heat_deflection_temperature",
      "label": "Heat deflection temperature, JCPE5",
      "value": 45,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "load": "1.8 MPa (264 PSI), method A",
        "standard": "ISO 75-1/-2 as printed"
      },
      "method": "Typical value printed on the manufacturer product page",
      "status": "ground",
      "source": "jc-jcpe5",
      "where": "Thermal Properties table, Heat Deflection Temperature method A row",
      "source_detail": {
        "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page, Specifications table",
        "id": "Product page, Specifications table",
        "url": "https://johncaunt.com/products/jcpe5/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Continuous allowable service temperature in air, JCPE5",
      "value": 80,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "duration": "20,000 h in air, as printed (20.000 hrs)"
      },
      "method": "Rating printed on the manufacturer product page",
      "status": "ground",
      "source": "jc-jcpe5",
      "where": "Thermal Properties table, Continuous allowable service temperature in air row",
      "source_detail": {
        "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page, Specifications table",
        "id": "Product page, Specifications table",
        "url": "https://johncaunt.com/products/jcpe5/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "min_service_temp",
      "label": "Minimum service temperature, JCPE5",
      "value": -20,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "minimum service temperature as printed, no test printed"
      },
      "method": "Rating printed on the manufacturer product page",
      "status": "ground",
      "source": "jc-jcpe5",
      "where": "Thermal Properties table, Min. service temperature row",
      "source_detail": {
        "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page, Specifications table",
        "id": "Product page, Specifications table",
        "url": "https://johncaunt.com/products/jcpe5/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, JCPE5",
      "value": 0.38,
      "bound": "exact",
      "unit": "W/(K.m)",
      "scope": "material",
      "conditions": {
        "temperature": "23 °C (73 °F)",
        "bound": "printed as ≥ 0.38, so this is a minimum"
      },
      "method": "Typical value printed on the manufacturer product page; no test standard printed",
      "status": "ground",
      "source": "jc-jcpe5",
      "where": "Thermal Properties table, Thermal conductivity at 23 °C row",
      "source_detail": {
        "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page, Specifications table",
        "id": "Product page, Specifications table",
        "url": "https://johncaunt.com/products/jcpe5/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of linear thermal expansion, JCPE5",
      "value": 135,
      "bound": "exact",
      "unit": "µm/(m.K)",
      "scope": "material",
      "conditions": {
        "temperature_range": "23 to 100 °C (73 °F to 210 °F)"
      },
      "method": "Value printed on the manufacturer product page; no test standard printed",
      "status": "ground",
      "source": "jc-jcpe5",
      "where": "Thermal Properties table, CTE 23 to 100 °C row",
      "source_detail": {
        "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page, Specifications table",
        "id": "Product page, Specifications table",
        "url": "https://johncaunt.com/products/jcpe5/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, JCPE5",
      "value": 21,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "standard": "ISO 527-1/-2 as printed",
        "specimen": "not printed"
      },
      "method": "Typical value printed on the manufacturer product page",
      "status": "ground",
      "source": "jc-jcpe5",
      "where": "Mechanical Properties table, Tensile strength row",
      "source_detail": {
        "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page, Specifications table",
        "id": "Product page, Specifications table",
        "url": "https://johncaunt.com/products/jcpe5/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Tensile strain at break, JCPE5",
      "value": 7,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "standard": "ISO 527-1/-2 as printed",
        "type": "at break, as printed (the page also prints 7 % at yield)"
      },
      "method": "Typical value printed on the manufacturer product page",
      "status": "ground",
      "source": "jc-jcpe5",
      "where": "Mechanical Properties table, Tensile strain (elongation) at break row",
      "source_detail": {
        "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page, Specifications table",
        "id": "Product page, Specifications table",
        "url": "https://johncaunt.com/products/jcpe5/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Tensile modulus of elasticity, JCPE5",
      "value": 1600,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "standard": "ISO 527-1/-2 as printed"
      },
      "method": "Typical value printed on the manufacturer product page",
      "status": "ground",
      "source": "jc-jcpe5",
      "where": "Mechanical Properties table, Tensile modulus of elasticity row",
      "source_detail": {
        "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page, Specifications table",
        "id": "Product page, Specifications table",
        "url": "https://johncaunt.com/products/jcpe5/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "moisture_absorption",
      "label": "Water absorption after 24 h immersion, JCPE5",
      "value": 0.1,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "duration": "24 h immersion",
        "temperature": "23 °C (73 °F)",
        "bound": "printed as < 0.1, so this is an upper limit",
        "standard": "ISO 62 as printed"
      },
      "method": "Value printed on the manufacturer product page",
      "status": "ground",
      "source": "jc-jcpe5",
      "where": "Miscellaneous table, Water absorption after 24h immersion row",
      "source_detail": {
        "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page, Specifications table",
        "id": "Product page, Specifications table",
        "url": "https://johncaunt.com/products/jcpe5/",
        "year": 2026,
        "kind": "datasheet",
        "license": "manufacturer web page, linked not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Specific gravity, MarShield borated polyethylene",
      "value": 1.01,
      "bound": "exact",
      "unit": "g/cc",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D792 as printed",
        "grade": "Borated polyethylene, MarShield data sheet N-BP-0616, 5 % boron by weight (brochure page)"
      },
      "method": "Typical value printed on the manufacturer data sheet",
      "status": "ground",
      "source": "marshield-bpe",
      "where": "Physical Properties table, Specific Gravity row",
      "source_detail": {
        "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
        "id": "N-BP-0616, physical, mechanical, thermal, electrical and chemical resistance tables",
        "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, linked not reproduced"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, MarShield borated polyethylene",
      "value": 16.6,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D638 as printed",
        "grade": "MarShield borated polyethylene"
      },
      "method": "Value printed on the manufacturer data sheet",
      "status": "ground",
      "source": "marshield-bpe",
      "where": "Mechanical Properties table, Tensile Strength row",
      "source_detail": {
        "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
        "id": "N-BP-0616, physical, mechanical, thermal, electrical and chemical resistance tables",
        "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, linked not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Tensile modulus, MarShield borated polyethylene",
      "value": 0.7667,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D638 as printed",
        "grade": "MarShield borated polyethylene"
      },
      "method": "Value printed on the manufacturer data sheet",
      "status": "ground",
      "source": "marshield-bpe",
      "where": "Mechanical Properties table, Tensile Modulas row (printed spelling)",
      "source_detail": {
        "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
        "id": "N-BP-0616, physical, mechanical, thermal, electrical and chemical resistance tables",
        "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, linked not reproduced"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Flexural yield strength, MarShield borated polyethylene",
      "value": 29.1,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D790 as printed",
        "grade": "MarShield borated polyethylene"
      },
      "method": "Value printed on the manufacturer data sheet",
      "status": "ground",
      "source": "marshield-bpe",
      "where": "Mechanical Properties table, Flexural Yield Strength row",
      "source_detail": {
        "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
        "id": "N-BP-0616, physical, mechanical, thermal, electrical and chemical resistance tables",
        "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, linked not reproduced"
      }
    },
    {
      "benchmark": "flexural_modulus",
      "label": "Flexural modulus, MarShield borated polyethylene",
      "value": 0.8729,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D790 as printed",
        "grade": "MarShield borated polyethylene"
      },
      "method": "Value printed on the manufacturer data sheet",
      "status": "ground",
      "source": "marshield-bpe",
      "where": "Mechanical Properties table, Flexural Modulas row (printed spelling)",
      "source_detail": {
        "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
        "id": "N-BP-0616, physical, mechanical, thermal, electrical and chemical resistance tables",
        "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, linked not reproduced"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break, MarShield borated polyethylene",
      "value": 4,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D638 as printed",
        "grade": "MarShield borated polyethylene"
      },
      "method": "Value printed on the manufacturer data sheet",
      "status": "ground",
      "source": "marshield-bpe",
      "where": "Mechanical Properties table, Elongation at Break row",
      "source_detail": {
        "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
        "id": "N-BP-0616, physical, mechanical, thermal, electrical and chemical resistance tables",
        "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, linked not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Linear CTE, MarShield borated polyethylene",
      "value": 198,
      "bound": "exact",
      "unit": "µm/m-°C",
      "scope": "material",
      "conditions": {
        "temperature_range": "-40 to 150 °C as printed (-40 to 302 °F)",
        "standard": "ASTM E831 as printed"
      },
      "method": "Value printed on the manufacturer data sheet",
      "status": "ground",
      "source": "marshield-bpe",
      "where": "Thermal Properties table, CTE linear row",
      "source_detail": {
        "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
        "id": "N-BP-0616, physical, mechanical, thermal, electrical and chemical resistance tables",
        "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, linked not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, MarShield borated polyethylene",
      "value": 128,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D3418 as printed",
        "grade": "MarShield borated polyethylene"
      },
      "method": "Printed on the data sheet as 128C °C; the value is recorded as 128 °C",
      "status": "ground",
      "source": "marshield-bpe",
      "where": "Thermal Properties table, Melting Point row",
      "source_detail": {
        "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
        "id": "N-BP-0616, physical, mechanical, thermal, electrical and chemical resistance tables",
        "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, linked not reproduced"
      }
    },
    {
      "benchmark": "heat_deflection_temperature",
      "label": "Heat deflection temperature, MarShield borated polyethylene",
      "value": 46.7,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "load": "1.8 MPa (264 psi)",
        "standard": "ASTM D648 as printed"
      },
      "method": "Value printed on the manufacturer data sheet",
      "status": "ground",
      "source": "marshield-bpe",
      "where": "Thermal Properties table, Deflection Temperature at 1.8 MPa row",
      "source_detail": {
        "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
        "id": "N-BP-0616, physical, mechanical, thermal, electrical and chemical resistance tables",
        "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, linked not reproduced"
      }
    },
    {
      "benchmark": "izod_impact_notched",
      "label": "Izod impact, notched, MarShield borated polyethylene",
      "value": 0.481,
      "bound": "exact",
      "unit": "J/cm",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D256 as printed",
        "specimen": "notched"
      },
      "method": "Value printed on the manufacturer data sheet, which also prints 0.900 ft-lb/in",
      "status": "ground",
      "source": "marshield-bpe",
      "where": "Mechanical Properties table, Izod Impact Notched row",
      "source_detail": {
        "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
        "id": "N-BP-0616, physical, mechanical, thermal, electrical and chemical resistance tables",
        "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, linked not reproduced"
      }
    },
    {
      "benchmark": "hardness_shore_d",
      "label": "Hardness, Shore D, MarShield borated polyethylene",
      "value": 71,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "standard": "ASTM D2240 as printed",
        "scale": "Shore D"
      },
      "method": "Value printed on the manufacturer data sheet",
      "status": "ground",
      "source": "marshield-bpe",
      "where": "Mechanical Properties table, Hardness Shore D row",
      "source_detail": {
        "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
        "id": "N-BP-0616, physical, mechanical, thermal, electrical and chemical resistance tables",
        "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf",
        "kind": "datasheet",
        "license": "manufacturer data sheet, linked not reproduced"
      }
    },
    {
      "benchmark": "absorbed_dose_per_spill",
      "label": "Absorbed dose per spill, boron-polyethylene at 5.35 g/cm2 (preliminary)",
      "value": 2.1,
      "bound": "exact",
      "unit": "µGy/Spill",
      "scope": "material",
      "conditions": {
        "beam": "190 MeV protons, Loma Linda University Medical Center proton synchrotron",
        "areal_density": "5.35 g/cm2",
        "sample": "boron-doped polyethylene as described in the Figure 7 caption (94.5 % polyethylene, 5.5 % boron)"
      },
      "method": "Tissue equivalent proportional counter measurement, preliminary; instrument error about 8 % as printed",
      "status": "ground",
      "source": "rojdev-2009-nasa",
      "where": "Table 1, row Boron -Poly 5.35",
      "source_detail": {
        "title": "Evaluation of Multi-Functional Materials for Deep Space Radiation Shielding",
        "id": "Rojdev, Atwell, Wilkins, Gersey and Badavi; NTRS 20090020691; 2009 NSMMS",
        "url": "https://ntrs.nasa.gov/api/citations/20090020691/downloads/20090020691.pdf",
        "year": 2009,
        "kind": "report",
        "license": "NASA public document"
      }
    },
    {
      "benchmark": "absorbed_dose_per_spill",
      "label": "Absorbed dose per spill, neat HDPE at 5.52 g/cm2 (comparison)",
      "value": 2.11,
      "bound": "exact",
      "unit": "µGy/Spill",
      "scope": "material",
      "conditions": {
        "beam": "190 MeV protons, Loma Linda University Medical Center proton synchrotron",
        "areal_density": "5.52 g/cm2"
      },
      "method": "Tissue equivalent proportional counter measurement, preliminary",
      "status": "ground",
      "source": "rojdev-2009-nasa",
      "where": "Table 1, row HDPE 5.52",
      "source_detail": {
        "title": "Evaluation of Multi-Functional Materials for Deep Space Radiation Shielding",
        "id": "Rojdev, Atwell, Wilkins, Gersey and Badavi; NTRS 20090020691; 2009 NSMMS",
        "url": "https://ntrs.nasa.gov/api/citations/20090020691/downloads/20090020691.pdf",
        "year": 2009,
        "kind": "report",
        "license": "NASA public document"
      }
    },
    {
      "benchmark": "dose_equivalent_per_spill",
      "label": "Dose equivalent per spill, boron-polyethylene at 5.35 g/cm2 (preliminary)",
      "value": 3.31,
      "bound": "exact",
      "unit": "µSv/Spill",
      "scope": "material",
      "conditions": {
        "beam": "190 MeV protons, Loma Linda University Medical Center proton synchrotron",
        "areal_density": "5.35 g/cm2"
      },
      "method": "Tissue equivalent proportional counter measurement, preliminary",
      "status": "ground",
      "source": "rojdev-2009-nasa",
      "where": "Table 1, row Boron -Poly 5.35, Dose Equivalent column",
      "source_detail": {
        "title": "Evaluation of Multi-Functional Materials for Deep Space Radiation Shielding",
        "id": "Rojdev, Atwell, Wilkins, Gersey and Badavi; NTRS 20090020691; 2009 NSMMS",
        "url": "https://ntrs.nasa.gov/api/citations/20090020691/downloads/20090020691.pdf",
        "year": 2009,
        "kind": "report",
        "license": "NASA public document"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Continuous sunlight",
      "headline": "MarShield rates continuous sunlight as Limited for its borated polyethylene.",
      "effect": "The chemical resistance table gives continuous sunlight as Limited. The table prints no UV exposure time, dose or retention figure.",
      "rating": "unknown",
      "conditions": {
        "basis": "qualitative rating in the chemical resistance table; no test method printed"
      },
      "source": "marshield-bpe",
      "where": "Chemical Resistance Properties table, Continuous Sunlight row"
    },
    {
      "environment": "Hot water or steam",
      "headline": "MarShield rates hot water and steam as Limited for borated polyethylene.",
      "effect": "The chemical resistance table gives hot water and steam as Limited, with no temperature or time printed.",
      "rating": "unknown",
      "conditions": {
        "basis": "qualitative rating; no test method printed"
      },
      "source": "marshield-bpe",
      "where": "Chemical Resistance Properties table, Hot Water / Steam row"
    },
    {
      "environment": "Chlorinated solvents, aliphatic and aromatic hydrocarbons, ketones and esters",
      "headline": "MarShield rates chlorinated solvents, hydrocarbons, ketones and esters as Unacceptable.",
      "effect": "The same table rates strong and weak acids, strong and weak alkalies, alcohols and inorganic salt solutions as Acceptable. Chlorinated solvents, aliphatic and aromatic hydrocarbons, and ketones and esters are rated Unacceptable.",
      "rating": "unknown",
      "conditions": {
        "basis": "qualitative rating; no concentration or temperature printed"
      },
      "source": "marshield-bpe",
      "where": "Chemical Resistance Properties table, rows Chlorinated Solvents, Hydrocarbons and Ketones, Esters"
    },
    {
      "environment": "Heat in service",
      "headline": "JCPE5 is rated to 80 °C continuous in air for 20,000 hours.",
      "effect": "Under a 1.8 MPa load the material softens at 45 °C (JCPE5) or 46.7 °C (MarShield), so the continuous rating is well below the melting point of 128 to 135 °C.",
      "rating": "unknown",
      "conditions": {
        "basis": "manufacturer rating in air; the load case is the heat deflection test at 1.8 MPa"
      },
      "source": "jc-jcpe5",
      "where": "Thermal Properties table, Continuous allowable service temperature in air row and Heat Deflection Temperature row"
    },
    {
      "environment": "Cold",
      "headline": "JCPE5 gives -20 °C as its minimum service temperature.",
      "effect": "No low-temperature impact or brittleness test for borated polyethylene was read in these sources, so the -20 °C rating is the manufacturer's only cold figure.",
      "rating": "unknown",
      "conditions": {
        "basis": "manufacturer rating; no test printed"
      },
      "source": "jc-jcpe5",
      "where": "Thermal Properties table, Min. service temperature row"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "Boron filler: the Materion SDS for elemental boron (boron pieces, CAS 7440-42-8, 100 %) says the substance does not meet GHS classification criteria, and that dust may irritate the respiratory tract, skin and eyes. That SDS covers pure boron, not the borated polyethylene.",
        "ghs": [],
        "source": "materion-boron-sds",
        "where": "Sections 2 (hazards identification), 3 (composition) and the toxicological section"
      },
      {
        "text": "Base polyethylene: the Borouge Borcoat HE3450 safety information sheet gives the product as not hazardous under SS 586: Part 2: 2022 (GHS, Singapore adaptation), with pictograms, signal word and hazard statements all printed as Nil. It notes that dust can irritate the respiratory tract and, mixed with air in critical proportions, can form a dust explosion risk.",
        "ghs": [],
        "source": "borouge-he3450-sds",
        "where": "Section 2 (hazards identification) and the fire-fighting text"
      }
    ],
    "failure_risks": [
      {
        "mode": "Softening under sustained load",
        "trigger": "A load-bearing shield held above about 45 °C under sustained load",
        "consequence": "Deformation at 1.8 MPa is the only load case in the sources read; no creep or long-term load test was read, so the consequence is not quantified.",
        "severity": "moderate",
        "source": "jc-jcpe5",
        "where": "Thermal Properties table, Heat Deflection Temperature row"
      },
      {
        "mode": "Lower dose benefit than expected from the boron",
        "trigger": "Preliminary proton-beam test at 190 MeV on boron-polyethylene samples at 5.35 g/cm2",
        "consequence": "The boron sample gave 2.10 µGy per spill against 2.11 µGy per spill for neat HDPE at 5.52 g/cm2. NASA reports similar performance to neat polyethylene and aluminium at comparable thickness, and says ground data were not final.",
        "severity": "moderate",
        "source": "rojdev-2009-nasa",
        "where": "Table 1 and Preliminary Results text"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "MarShield says the standard 48 x 96 x 1 inch sheet can be cut with standard woodworking tools; no handling hazard is printed on that data sheet.",
        "source": "marshield-bpe"
      },
      {
        "text": "Keep dust down when machining. The boron SDS advises minimising dust generation and using exhaust ventilation where dust forms.",
        "source": "materion-boron-sds"
      },
      {
        "text": "Dust from the base polyethylene can irritate the respiratory tract, and the Borouge sheet notes a dust explosion risk in air at critical proportions.",
        "source": "borouge-he3450-sds"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "radiation-shielding",
      "device": "Neutron shield sheets, vault doors and storage containers",
      "example": "MarShield lists medical vaults and doors, particle accelerators, hot cells, nuclear storage and transport containers, and nuclear detection systems as uses of its borated polyethylene.",
      "source": "marshield-bpe",
      "where": "Opening text, first page of the borated polyethylene data sheet"
    },
    {
      "application": "radiation-shielding",
      "device": "Neutron shield in nuclear installations (JCPE5)",
      "example": "JCS Nuclear Solutions describes JCPE5 as a 5 % boron loaded polyethylene neutron shield, developed for nuclear installations where low and intermediate neutron flux is expected and elevated temperatures are not.",
      "source": "jc-jcpe5",
      "where": "Product description text"
    },
    {
      "application": "radiation-shielding",
      "device": "Space radiation shield, preliminary study",
      "example": "NASA's 2009 study tested boron-polyethylene in a 190 MeV proton beam and modelled thicker samples. In simulation, the 5 % borated grade was a better mitigator than the 0.86 % and 30 % grades, but the ground data were preliminary.",
      "source": "rojdev-2009-nasa",
      "where": "Figure 1 text and Summary"
    }
  ],
  "supply": [
    {
      "subject": "Boron (filler element and borate feedstock)",
      "abundance": "USGS reserves printed in thousand metric tons: Turkey 950,000; Chile 35,000; Russia 40,000; China 9,100; Peru 4,000; United States 48,000.",
      "producers": [],
      "critical_lists": [
        {
          "list": "USGS 2025 critical minerals list, boron added (USGS Mineral Commodity Summaries 2026)",
          "listed": true
        }
      ],
      "substitutes": [],
      "source": "usgs-mcs2026-boron",
      "where": "World Production and Reserves table, 2025 column; Events, Trends and Issues; Import Sources line"
    },
    {
      "subject": "Boron (US import sources)",
      "producers": [],
      "critical_lists": [],
      "substitutes": [],
      "source": "usgs-mcs2026-boron",
      "where": "Imports for consumption, Import Sources line"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page",
      "type": "datasheet",
      "url": "https://johncaunt.com/products/jcpe5/",
      "year": 2026
    },
    {
      "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
      "type": "datasheet",
      "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf"
    },
    {
      "title": "Evaluation of Multi-Functional Materials for Deep Space Radiation Shielding (Rojdev, Atwell, Wilkins, Gersey, Badavi), NTRS 20090020691",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/20090020691/downloads/20090020691.pdf",
      "year": 2009
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Boron",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-boron.pdf",
      "year": 2026
    },
    {
      "title": "Materion Safety Data Sheet, Boron pieces (SDS B-MSDS0071, revision 07-14-2015)",
      "type": "sds",
      "url": "https://www.physics.purdue.edu/primelab/safety/MSDS/SDS/boron%20%20-%20Materion..pdf",
      "year": 2015
    },
    {
      "title": "Borouge Borcoat HE3450 safety information sheet (polyethylene)",
      "type": "sds",
      "url": "https://www.borouge.com/en/e-service/DataSheets/Borcoat%20HE3450/HE3450_SIS.pdf"
    },
    {
      "title": "NIST Atomic Weights and Isotopic Compositions for All Elements",
      "type": "database",
      "url": "https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=B&all=all&ascii=html"
    }
  ],
  "gaps": [
    "No safety data sheet for the 5 % borated polyethylene product was read. The hazard entries use an elemental boron SDS (Materion) and a base polyethylene SDS (Borouge), which are different products.",
    "No neutron capture cross-section, neutron attenuation coefficient or half-value thickness for any borated grade was found. NASA gives proton dose only.",
    "No source read names the boron compound in the commercial grades. JCPE5 says only the added boron compound absorbs the neutrons.",
    "Radiation ageing of borated polyethylene (gamma, neutron, or long UV exposure) was not found. The only sunlight rating is MarShield's Limited, with no test figure.",
    "Environment tags (lunar-day, deep-space) are left empty. The NASA paper discusses lunar surface and deep-space cases but gives no test condition tied to the product.",
    "Production and producers of the base polyethylene were not found in a source read for this profile.",
    "JCPE5 Charpy impact values are printed unclearly (15,0 and 5C) and are left out. Izod, flexural strength and flexural modulus are printed as dashes on the JCPE5 page.",
    "MarShield's chemical resistance is qualitative (Acceptable, Limited, Unacceptable). No numeric exposure test was printed.",
    "Notched Izod impact, Shore D hardness, and absorbed dose or dose equivalent per spill use snake_case names that are not in the property canon.",
    "The NASA dose values are preliminary: one 190 MeV proton beam, TEPC error about 8 %, the Li-polyethylene target corrupted, and the boron coupons were 5.5 % boron per the Figure 7 caption, not the 5 % commercial grade.",
    "JCPE5 (1.04 g/cm3, 135 °C) and MarShield (1.01 g/cc, 128 °C) differ on density and melting point. Both values are recorded and not averaged.",
    "No low-temperature brittleness, outgassing or atomic oxygen erosion value for borated polyethylene was found.",
    "Volume resistivity of JCPE5 (printed 10E13) and surface resistivity of MarShield (printed >= 1.0e+12 ohm) are left out because the printed form could not be matched to a plain number in the source check."
  ],
  "story": {
    "why": "Borated polyethylene combines a hydrogen-rich polymer with boron, which captures neutrons. JCPE5 is a 5 % boron grade with a density of 1.04 g/cm3 and a melting temperature of 135 °C, both per the manufacturer's page. MarShield's borated polyethylene is printed as 1.01 g/cc with a melting point of 128 °C, so the two datasheets disagree slightly and both values are shown.",
    "uses": [
      {
        "where": "Nuclear facilities",
        "line": "MarShield lists vault doors, particle accelerators, hot cells and nuclear storage and transport containers as uses. JCS Nuclear Solutions sells JCPE5 as a neutron shield for nuclear installations."
      },
      {
        "where": "Space radiation research",
        "line": "NASA tested boron-polyethylene in a 190 MeV proton beam in 2009. The results were preliminary, and the study says ground data were still to come."
      }
    ],
    "can_do": [
      {
        "label": "Shield neutrons",
        "line": "JCPE5 is loaded with 5 % boron. The page says the hydrogen slows fast neutrons and the boron absorbs the slowed neutrons.",
        "scope": "material",
        "value": "5 % boron"
      },
      {
        "label": "Stay stiff at room temperature",
        "line": "JCPE5 prints a tensile modulus of 1600 MPa (ISO 527). MarShield prints 0.7667 GPa (ASTM D638) for its product, so the two sheets are shown side by side.",
        "benchmark": "elastic_modulus",
        "scope": "material",
        "value": "1600 MPa"
      },
      {
        "label": "Take continuous heat",
        "line": "JCPE5 gives 80 °C as the continuous allowable service temperature in air for 20,000 hours.",
        "benchmark": "max_service_temp",
        "scope": "material",
        "value": "80 °C"
      }
    ],
    "compare": "Borated polyethylene is a polymer shield with a density of 1.04 g/cm3 on one datasheet and 1.01 g/cc on the other. The sources read give no density or dose comparison with a metal or concrete alternative, so no ranking is made. NASA's preliminary Table 1 puts the boron grade close to neat HDPE at similar thickness, and it does not show a clear advantage at 5.35 g/cm2.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Heat deflection temperature",
        "benchmark": "heat_deflection_temperature",
        "scope": "material"
      },
      {
        "label": "Absorbed dose per spill at about 5 g/cm2",
        "benchmark": "absorbed_dose_per_spill",
        "scope": "material"
      }
    ],
    "handling": [
      "Specify the grade and boron content, since the sources print 5 % by weight and the two datasheets differ in property values.",
      "Check the current supplier SDS for the grade you buy. No SDS for the 5 % borated product was read.",
      "Keep dust down when cutting, since the boron and polyethylene sheets both mention dust hazards.",
      "Keep the material below about 45 °C under sustained load."
    ],
    "good_for": [
      "Neutron shielding at low to moderate temperature: JCPE5 states it suits low and intermediate neutron flux where elevated temperatures are not expected.",
      "Shielding around vaults, doors and containers in nuclear and medical facilities, as MarShield describes.",
      "Low-cost shielding: MarShield describes its sheet as a lightweight, cost-effective shielding solution."
    ],
    "watch_out": [
      "Heat under load: deflection starts at 45 °C (JCPE5) and 46.7 °C (MarShield) at 1.8 MPa.",
      "Dose benefit: the 2009 NASA preliminary test found no clear advantage over neat HDPE at similar thickness.",
      "Solvents and sunlight: MarShield rates continuous sunlight as Limited, and chlorinated solvents, hydrocarbons, ketones and esters as Unacceptable."
    ],
    "verdict": "Borated polyethylene is a low-cost neutron shield at 5 % boron by weight, with densities of 1.04 and 1.01 printed by the two datasheets and a heat limit near 45 °C under load. The one space test read was preliminary and showed no clear benefit over neat polyethylene at similar thickness, so ground data are the next check.",
    "recipe": {
      "line": "Borated polyethylene is polyethylene, (C2H4)n, made from ethylene, with a boron filler. The grades read carry 5 % boron by weight (MarShield and JCPE5). The sources do not name the boron compound, so the recipe lists boron as an element.",
      "parts": [
        {
          "name": "Carbon",
          "symbol": "C",
          "role": "Two carbons per ethylene repeat unit, forming the polymer backbone."
        },
        {
          "name": "Hydrogen",
          "symbol": "H",
          "role": "Four hydrogens per repeat unit. JCPE5 says the high hydrogen content slows fast neutrons."
        },
        {
          "name": "Boron",
          "symbol": "B",
          "role": "Neutron absorber. JCPE5 says the added boron compound absorbs the slowed neutrons."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "Base polyethylene and elemental boron are both described as not classified under GHS in the sheets read. No safety data sheet for the 5 % borated product was read, so its own classification is not verified.",
        "points": [
          {
            "label": "Base polymer",
            "line": "The Borouge polyethylene sheet prints no pictogram, signal word or hazard statement under SS 586: Part 2: 2022."
          },
          {
            "label": "Boron filler",
            "line": "The Materion boron sheet says the substance does not meet GHS criteria, and that dust may irritate the respiratory tract, skin and eyes."
          },
          {
            "label": "Dust",
            "line": "Keep machining dust down and ventilated, as the boron sheet advises."
          }
        ],
        "level": 1,
        "verdict": "Not classified in the sheets read; product sheet not found"
      },
      {
        "title": "If it fails",
        "lead": "Two failure routes come from the sources: heat under load, and a weaker boron benefit than expected in one preliminary test.",
        "points": [
          {
            "label": "Heat",
            "line": "The heat deflection temperature is 45 °C (JCPE5) or 46.7 °C (MarShield) at 1.8 MPa, well below the melting point of 128 to 135 °C."
          },
          {
            "label": "Shielding",
            "line": "A preliminary 190 MeV proton test gave 2.10 µGy per spill for boron-polyethylene at 5.35 g/cm2 against 2.11 µGy per spill for neat HDPE at 5.52 g/cm2."
          }
        ]
      }
    ]
  },
  "updated": "2026-11-01",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 25,
    "unreachable": 0,
    "caveats": 6,
    "note": "Values read by an AI assistant on 2026-11-01 from the pages named in each entry. The Marshield and NASA PDFs were read as text with pdftotext. JCPE5 values were confirmed in the page HTML. Caveats: JCPE5 and MarShield differ on density, melting point, tensile strength and HDT; the NASA dose values are preliminary and from a 5.5 % boron coupon; the Marshield data sheet prints no grade name; no SDS for the 5 % borated product was read; the JCPE5 volume resistivity and MarShield surface resistivity were dropped after the value check."
  },
  "sources": {
    "jc-jcpe5": {
      "title": "5% Borated Polyethylene (JCPE5), JCS Nuclear Solutions product page, Specifications table",
      "id": "Product page, Specifications table",
      "url": "https://johncaunt.com/products/jcpe5/",
      "year": 2026,
      "kind": "datasheet",
      "license": "manufacturer web page, linked not reproduced"
    },
    "marshield-bpe": {
      "title": "Borated Polyethylene, Neutron Shielding, MarShield data sheet N-BP-0616",
      "id": "N-BP-0616, physical, mechanical, thermal, electrical and chemical resistance tables",
      "url": "https://marshield.com/publications/Nuclear_BoratedPolyethylene.pdf",
      "kind": "datasheet",
      "license": "manufacturer data sheet, linked not reproduced"
    },
    "rojdev-2009-nasa": {
      "title": "Evaluation of Multi-Functional Materials for Deep Space Radiation Shielding",
      "id": "Rojdev, Atwell, Wilkins, Gersey and Badavi; NTRS 20090020691; 2009 NSMMS",
      "url": "https://ntrs.nasa.gov/api/citations/20090020691/downloads/20090020691.pdf",
      "year": 2009,
      "kind": "report",
      "license": "NASA public document"
    },
    "usgs-mcs2026-boron": {
      "title": "Mineral Commodity Summaries 2026: Boron (U.S. Geological Survey)",
      "id": "mcs2026-boron, World Production and Reserves table, Events, Trends and Issues",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-boron.pdf",
      "year": 2026,
      "kind": "report",
      "license": "US government publication"
    },
    "materion-boron-sds": {
      "title": "Safety Data Sheet, Boron pieces, Materion Advanced Chemicals",
      "id": "SDS B-MSDS0071, version 02, revision 07-14-2015",
      "url": "https://www.physics.purdue.edu/primelab/safety/MSDS/SDS/boron%20%20-%20Materion..pdf",
      "year": 2015,
      "kind": "datasheet",
      "license": "supplier SDS, linked not reproduced"
    },
    "borouge-he3450-sds": {
      "title": "Borcoat HE3450 safety information sheet, Borouge (polyethylene)",
      "id": "SIS, polyethylene; GHS classification under SS 586 Part 2 (2022) as printed",
      "url": "https://www.borouge.com/en/e-service/DataSheets/Borcoat%20HE3450/HE3450_SIS.pdf",
      "kind": "datasheet",
      "license": "supplier SDS, linked not reproduced"
    },
    "nist-atomic-weights": {
      "title": "NIST Atomic Weights and Isotopic Compositions for All Elements (H, B and C rows)",
      "id": "Standard atomic weight intervals as printed: H [1.007 84, 1.008 11]; B [10.806, 10.821]; C [12.0096, 12.0116]",
      "url": "https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=B&all=all&ascii=html",
      "kind": "database",
      "license": "US government data"
    },
    "wikipedia-polyethylene": {
      "title": "Polyethylene, Wikipedia",
      "id": "Introduction and infobox: chemical formula (C2H4)n; Manufacturing process, monomer ethylene C2H4",
      "url": "https://en.wikipedia.org/wiki/Polyethylene",
      "kind": "web",
      "license": "CC BY-SA 4.0, linked not reproduced"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/borated-polyethylene/"
}