{
  "spore": "profile",
  "id": "epdm",
  "spore_version": "0.2",
  "family": "polyolefins",
  "name": "Ethylene propylene diene monomer rubber (EPDM)",
  "abbreviation": "EPDM",
  "role": "Seal, O-ring and hose elastomer for hot water, steam and weathering service",
  "category": "polymers",
  "type": "polyolefins",
  "summary": "EPDM (ethylene propylene diene monomer) is a synthetic terpolymer rubber made from ethylene, propylene and a small amount of a diene that carries the cure sites. Polymax's sulphur-cured 70 Shore A O-ring compound is rated -30 to 125 °C, and its peroxide-cured 70 Shore A compound -30 to 150 °C. Parker's O-Ring Handbook gives up to 150 °C in water and steam (204 °C maximum), cold flexibility to about -57 °C, and says EPDM deteriorates in petroleum lubricants.\n",
  "best_for": "Seals for hot water, steam, ozone and weathering, and for glycol or silicone brake fluids (Polymax, Parker)",
  "weakest_at": "Petroleum lubricants (Parker says it deteriorates in them), and UV exposure, which crosslinks and oxidises the rubber in the one UV-aged study read here",
  "identity": {
    "formula": "Terpolymer of ethylene, propylene and a diene (ethylidene norbornene, dicyclopentadiene or vinyl norbornene). Saturated polyethylene-type backbone with a small diene comonomer that provides the cure sites.",
    "designations": [
      {
        "system": "ASTM",
        "code": "D1418",
        "note": "M-class elastomer with a saturated polyethylene-type chain (EPDM)",
        "source": "wikipedia-epdm",
        "where": "Classification section, M-Class rubber under ASTM D-1418"
      }
    ],
    "source": "wikipedia-epdm",
    "where": "Composition section (monomers, diene types, diene content); the Polymax sulphur-cured datasheet describes EPDM as a terpolymer of ethylene, propylene and diene monomers"
  },
  "tags": {
    "environments": [],
    "stresses": [
      "uv",
      "extreme-heat",
      "extreme-cold",
      "vacuum-and-outgassing",
      "total-radiation-dose"
    ],
    "applications": [
      "mechanisms"
    ]
  },
  "properties": [
    {
      "benchmark": "max_service_temp",
      "label": "Heat resistance in water and steam (general EPDM)",
      "value": 150,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "medium": "water and/or steam",
        "note": "Parker gives 204 °C (400 °F) as the maximum, with shorter life at that level"
      },
      "method": "Statement in the Parker O-Ring Handbook, EPDM section",
      "status": "ground",
      "source": "parker-handbook",
      "where": "Section 2.2.4 Ethylene Propylene Rubber (EPR, EPDM), heat resistance",
      "source_detail": {
        "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
        "id": "Parker O-Ring Handbook, copy at the University of Arizona",
        "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
        "year": 2022,
        "kind": "handbook",
        "license": "Manufacturer handbook, cited"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Hot water and steam with special compounds",
      "value": 260,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "medium": "hot water and steam",
        "compound": "special compounds (Parker does not name them in this statement)"
      },
      "method": "Statement in the Parker O-Ring Handbook, EPDM section",
      "status": "ground",
      "source": "parker-handbook",
      "where": "Section 2.2.4, chemical resistance (paragraph beginning Hot water and steam up to 149 °C)",
      "source_detail": {
        "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
        "id": "Parker O-Ring Handbook, copy at the University of Arizona",
        "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
        "year": 2022,
        "kind": "handbook",
        "license": "Manufacturer handbook, cited"
      }
    },
    {
      "benchmark": "min_service_temp",
      "label": "Cold flexibility (general EPDM)",
      "value": -57,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "Parker wording is approximately -57 °C (-70 °F)"
      },
      "method": "Statement in the Parker O-Ring Handbook, EPDM section",
      "status": "ground",
      "source": "parker-handbook",
      "where": "Section 2.2.4, cold flexibility",
      "source_detail": {
        "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
        "id": "Parker O-Ring Handbook, copy at the University of Arizona",
        "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
        "year": 2022,
        "kind": "handbook",
        "license": "Manufacturer handbook, cited"
      }
    },
    {
      "benchmark": "cte",
      "label": "Linear thermal expansion coefficient, 24 to 191 °C",
      "value": 0.000089,
      "bound": "exact",
      "unit": "in/in/°F",
      "scope": "material",
      "conditions": {
        "range": "24 to 191 °C (75 to 375 °F)",
        "basis": "Ethylene Propylene row; printed as 8.9 x 10-5"
      },
      "method": "Parker table of linear thermal expansion, printed in US units",
      "status": "ground",
      "source": "parker-handbook",
      "where": "Table Linear Thermal Expansion of Typical Elastomers, Ethylene Propylene row (beside section 2.4.19)",
      "source_detail": {
        "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
        "id": "Parker O-Ring Handbook, copy at the University of Arizona",
        "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
        "year": 2022,
        "kind": "handbook",
        "license": "Manufacturer handbook, cited"
      }
    },
    {
      "benchmark": "vacuum_weight_loss",
      "label": "Weight loss in vacuum, E0515-80 ethylene propylene compound",
      "value": 0.39,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "vacuum": "about 1 x 10-6 torr",
        "time": "336 h",
        "temperature": "25 °C"
      },
      "method": "Parker weight loss of compounds in vacuum test, which is not the ASTM E595 TML method",
      "status": "ground",
      "source": "parker-handbook",
      "where": "Section 3.11.1 Vacuum Weight Loss, Table 3-19 (row E0515-80)",
      "source_detail": {
        "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
        "id": "Parker O-Ring Handbook, copy at the University of Arizona",
        "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
        "year": 2022,
        "kind": "handbook",
        "license": "Manufacturer handbook, cited"
      }
    },
    {
      "benchmark": "vacuum_weight_loss",
      "label": "Weight loss in vacuum, E0692-75 ethylene propylene compound",
      "value": 0.76,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "vacuum": "about 1 x 10-6 torr",
        "time": "336 h",
        "temperature": "25 °C"
      },
      "method": "Parker weight loss of compounds in vacuum test, which is not the ASTM E595 TML method",
      "status": "ground",
      "source": "parker-handbook",
      "where": "Section 3.11.1 Vacuum Weight Loss, Table 3-19 (row E0692-75)",
      "source_detail": {
        "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
        "id": "Parker O-Ring Handbook, copy at the University of Arizona",
        "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
        "year": 2022,
        "kind": "handbook",
        "license": "Manufacturer handbook, cited"
      }
    },
    {
      "benchmark": "vacuum_weight_loss",
      "label": "Weight loss in vacuum, E0529-60 ethylene propylene compound",
      "value": 0.92,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "vacuum": "about 1 x 10-6 torr",
        "time": "336 h",
        "temperature": "25 °C"
      },
      "method": "Parker weight loss of compounds in vacuum test, which is not the ASTM E595 TML method",
      "status": "ground",
      "source": "parker-handbook",
      "where": "Section 3.11.1 Vacuum Weight Loss, Table 3-19 (row E0529-60)",
      "source_detail": {
        "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
        "id": "Parker O-Ring Handbook, copy at the University of Arizona",
        "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
        "year": 2022,
        "kind": "handbook",
        "license": "Manufacturer handbook, cited"
      }
    },
    {
      "benchmark": "compression_set",
      "label": "Compression set after gamma dose, E0740-75 ethylene propylene",
      "value": 28.6,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "dose": "10^7 rad gamma (the PDF prints the exponent as a superscript; read as 10^7 from the table header and footnote 1)",
        "temperature": "room temperature",
        "compound": "E0740-75, polymer ethylene propylene"
      },
      "method": "Parker radiation table, compression set after exposure to gamma radiation",
      "status": "ground",
      "source": "parker-handbook",
      "where": "Section 3.9.14 Radiation, Data on Radiation Resistant Compounds table",
      "source_detail": {
        "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
        "id": "Parker O-Ring Handbook, copy at the University of Arizona",
        "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
        "year": 2022,
        "kind": "handbook",
        "license": "Manufacturer handbook, cited"
      }
    },
    {
      "benchmark": "compression_set",
      "label": "Compression set after gamma dose, E0515-80 ethylene propylene",
      "value": 46.6,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "dose": "10^7 rad gamma (superscript in PDF; read as 10^7 as for E0740-75)",
        "temperature": "room temperature",
        "compound": "E0515-80, polymer ethylene propylene"
      },
      "method": "Parker radiation table, compression set after exposure to gamma radiation",
      "status": "ground",
      "source": "parker-handbook",
      "where": "Section 3.9.14 Radiation, Data on Radiation Resistant Compounds table",
      "source_detail": {
        "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
        "id": "Parker O-Ring Handbook, copy at the University of Arizona",
        "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
        "year": 2022,
        "kind": "handbook",
        "license": "Manufacturer handbook, cited"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Temperature for 90% set after 1000 h, E0740-75 ethylene propylene",
      "value": 177,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "compound": "E0740-75",
        "basis": "temperature at which a 0.139 in cross-section ring takes 90% compression set after 1000 h, not exposed to radiation or fluids"
      },
      "method": "Parker radiation table, footnote 2",
      "status": "ground",
      "source": "parker-handbook",
      "where": "Section 3.9.14 Radiation, Data on Radiation Resistant Compounds table, footnote 2",
      "source_detail": {
        "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
        "id": "Parker O-Ring Handbook, copy at the University of Arizona",
        "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
        "year": 2022,
        "kind": "handbook",
        "license": "Manufacturer handbook, cited"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Temperature for 90% set after 1000 h, E0515-80 ethylene propylene",
      "value": 149,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "compound": "E0515-80",
        "basis": "as for E0740-75: 90% compression set after 1000 h, not exposed to radiation or fluids"
      },
      "method": "Parker radiation table, footnote 2",
      "status": "ground",
      "source": "parker-handbook",
      "where": "Section 3.9.14 Radiation, Data on Radiation Resistant Compounds table, footnote 2",
      "source_detail": {
        "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
        "id": "Parker O-Ring Handbook, copy at the University of Arizona",
        "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
        "year": 2022,
        "kind": "handbook",
        "license": "Manufacturer handbook, cited"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Operating temperature range, sulphur-cured 70 ShA O-ring",
      "value": 125,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "cure": "sulphur-based",
        "grade": "EPDM 70 ShA, black"
      },
      "method": "Operating temperature range printed on the datasheet",
      "status": "ground",
      "source": "polymax-sulphur",
      "where": "Operating temperature range line",
      "source_detail": {
        "title": "EPDM 70 ShA sulphur-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "min_service_temp",
      "label": "Operating temperature range, lower limit, sulphur-cured 70 ShA O-ring",
      "value": -30,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "cure": "sulphur-based",
        "grade": "EPDM 70 ShA, black"
      },
      "method": "Operating temperature range printed on the datasheet",
      "status": "ground",
      "source": "polymax-sulphur",
      "where": "Operating temperature range line",
      "source_detail": {
        "title": "EPDM 70 ShA sulphur-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "min_service_temp",
      "label": "Low temperature resistance, sulphur-cured 70 ShA",
      "value": -40,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "test": "ASTM D 1329 TR10",
        "cure": "sulphur-based"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-sulphur",
      "where": "Physical property table, Low Temperature Resistance row",
      "source_detail": {
        "title": "EPDM 70 ShA sulphur-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Hardness, sulphur-cured 70 ShA",
      "value": 71,
      "bound": "exact",
      "unit": "Shore A",
      "scope": "material",
      "conditions": {
        "test": "ASTM D 2240",
        "grade": "EPDM 70 ShA, black"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-sulphur",
      "where": "Physical property table, Hardness row",
      "source_detail": {
        "title": "EPDM 70 ShA sulphur-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, sulphur-cured 70 ShA",
      "value": 10.5,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "test": "ASTM D 412",
        "cure": "sulphur-based"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-sulphur",
      "where": "Physical property table, Tensile Strength row",
      "source_detail": {
        "title": "EPDM 70 ShA sulphur-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break, sulphur-cured 70 ShA",
      "value": 255,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "test": "ASTM D 412",
        "cure": "sulphur-based"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-sulphur",
      "where": "Physical property table, Elongation row",
      "source_detail": {
        "title": "EPDM 70 ShA sulphur-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "density",
      "label": "Specific gravity, sulphur-cured 70 ShA",
      "value": 1.19,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "test": "ASTM D 297",
        "tolerance": "printed as 1.19 +/- 0.03"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-sulphur",
      "where": "Physical property table, Specific Gravity row",
      "source_detail": {
        "title": "EPDM 70 ShA sulphur-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "compression_set",
      "label": "Compression set, sulphur-cured 70 ShA",
      "value": 38,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "test": "ASTM D 395 B",
        "time": "22 h",
        "temperature": "125 °C"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-sulphur",
      "where": "Physical property table, Compression Set row",
      "source_detail": {
        "title": "EPDM 70 ShA sulphur-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "tear_strength",
      "label": "Tear resistance, sulphur-cured 70 ShA",
      "value": 49,
      "bound": "exact",
      "unit": "N/mm",
      "scope": "material",
      "conditions": {
        "test": "ASTM D 624 C"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-sulphur",
      "where": "Physical property table, Tear Resistance row",
      "source_detail": {
        "title": "EPDM 70 ShA sulphur-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Operating temperature range, peroxide-cured 70 ShA O-ring",
      "value": 150,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "cure": "peroxide",
        "grade": "EPDM 70 ShA peroxide cured, black"
      },
      "method": "Operating temperature range printed on the datasheet",
      "status": "ground",
      "source": "polymax-peroxide",
      "where": "Operating temperature range line",
      "source_detail": {
        "title": "EPDM 70 ShA peroxide-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_peroxide_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_peroxide_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "min_service_temp",
      "label": "Operating temperature range, lower limit, peroxide-cured 70 ShA O-ring",
      "value": -30,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "cure": "peroxide",
        "grade": "EPDM 70 ShA peroxide cured, black"
      },
      "method": "Operating temperature range printed on the datasheet",
      "status": "ground",
      "source": "polymax-peroxide",
      "where": "Operating temperature range line",
      "source_detail": {
        "title": "EPDM 70 ShA peroxide-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_peroxide_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_peroxide_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "min_service_temp",
      "label": "Low temperature resistance, peroxide-cured 70 ShA",
      "value": -42,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "test": "ISO 2921",
        "criterion": "printed as < -37 °C in the test column",
        "cure": "peroxide"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-peroxide",
      "where": "Physical property table, Low Temperature Resistance row",
      "source_detail": {
        "title": "EPDM 70 ShA peroxide-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_peroxide_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_peroxide_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "hardness",
      "label": "Hardness, peroxide-cured 70 ShA",
      "value": 70,
      "bound": "exact",
      "unit": "Shore A",
      "scope": "material",
      "conditions": {
        "test": "ASTM D 2240",
        "cure": "peroxide"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-peroxide",
      "where": "Physical property table, Hardness row",
      "source_detail": {
        "title": "EPDM 70 ShA peroxide-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_peroxide_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_peroxide_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, peroxide-cured 70 ShA",
      "value": 17,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "test": "ISO 37 type 2",
        "cure": "peroxide"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-peroxide",
      "where": "Physical property table, Tensile Strength row",
      "source_detail": {
        "title": "EPDM 70 ShA peroxide-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_peroxide_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_peroxide_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break, peroxide-cured 70 ShA",
      "value": 220,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "test": "ISO 37 type 2",
        "cure": "peroxide"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-peroxide",
      "where": "Physical property table, Elongation row",
      "source_detail": {
        "title": "EPDM 70 ShA peroxide-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_peroxide_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_peroxide_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "density",
      "label": "Specific gravity, peroxide-cured 70 ShA",
      "value": 1.14,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "test": "ISO 2781 A",
        "cure": "peroxide"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-peroxide",
      "where": "Physical property table, Specific Gravity row",
      "source_detail": {
        "title": "EPDM 70 ShA peroxide-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_peroxide_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_peroxide_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "compression_set",
      "label": "Compression set, peroxide-cured 70 ShA",
      "value": 13,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "test": "ISO 815 B",
        "cure": "peroxide",
        "note": "time and temperature not printed in the table row"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-peroxide",
      "where": "Physical property table, Compression Set row",
      "source_detail": {
        "title": "EPDM 70 ShA peroxide-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_peroxide_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_peroxide_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "tear_strength",
      "label": "Tear resistance, peroxide-cured 70 ShA",
      "value": 32,
      "bound": "exact",
      "unit": "N/mm",
      "scope": "material",
      "conditions": {
        "test": "ISO 34-1 C",
        "cure": "peroxide"
      },
      "method": "Typical value from the supplier datasheet",
      "status": "ground",
      "source": "polymax-peroxide",
      "where": "Physical property table, Tear Resistance row",
      "source_detail": {
        "title": "EPDM 70 ShA peroxide-cured O-ring datasheet, Polymax",
        "id": "Polymax datasheet epdm_70sha_peroxide_oring",
        "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_peroxide_oring_polymax.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Tested operating range, EP70 EPDM compound",
      "value": 145,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "compound": "EP70 (EPDM), black",
        "column": "tested value; the required column is n/a"
      },
      "method": "Technical data sheet, operating temperature range, tested column",
      "status": "ground",
      "source": "polymax-ep70",
      "where": "Thermal Properties, Operating Temperature Range row",
      "source_detail": {
        "title": "EP70 EPDM technical data sheet, Polymax",
        "id": "Polymax technical data sheet ORing_EPDM-70",
        "url": "https://www.polymax.co.uk//media/documents/Datasheet/ORing_EPDM-70.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "min_service_temp",
      "label": "Tested operating range lower limit, EP70 EPDM compound",
      "value": -45,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "compound": "EP70 (EPDM), black",
        "column": "tested value"
      },
      "method": "Technical data sheet, operating temperature range, tested column",
      "status": "ground",
      "source": "polymax-ep70",
      "where": "Thermal Properties, Operating Temperature Range row",
      "source_detail": {
        "title": "EP70 EPDM technical data sheet, Polymax",
        "id": "Polymax technical data sheet ORing_EPDM-70",
        "url": "https://www.polymax.co.uk//media/documents/Datasheet/ORing_EPDM-70.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "compression_set",
      "label": "Compression set, EP70 EPDM compound",
      "value": 13,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "test": "70 °C for 22 hours",
        "compound": "EP70 (EPDM), black"
      },
      "method": "Tested value on the technical data sheet",
      "status": "ground",
      "source": "polymax-ep70",
      "where": "Thermal Properties, Compression Set Test row, tested column",
      "source_detail": {
        "title": "EP70 EPDM technical data sheet, Polymax",
        "id": "Polymax technical data sheet ORing_EPDM-70",
        "url": "https://www.polymax.co.uk//media/documents/Datasheet/ORing_EPDM-70.pdf",
        "kind": "datasheet",
        "license": "Supplier datasheet, cited"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "DMA transition temperature, new UV-weathering EPDM housing",
      "value": -42,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "material": "industrial EPDM housing with aluminium trihydrate filler (Table 1 of the paper), peroxide cured",
        "test": "DMA, dual cantilever, 1 Hz, 3 °C/min"
      },
      "method": "Temperature label on the tan delta plot in Fig. 3 legend, read as the DMA transition",
      "status": "ground",
      "source": "bencherif-2019",
      "where": "Figure 3 legend (tan delta vs temperature), New sample",
      "source_detail": {
        "title": "Multiscale Analysis of the Polymeric Insulators Degradation in Simulated Arid Environment Conditions: Cross-Correlation Assessment, Journal of Electrical Engineering and Technology",
        "id": "DOI 10.1007/s42835-019-00217-7",
        "url": "https://orbi.umons.ac.be/bitstream/20.500.12907/37612/1/Bencherif_et_al-2019-Journal_of_Electrical_Engineering__Technology.pdf",
        "year": 2019,
        "kind": "paper",
        "license": "Springer, cited"
      }
    },
    {
      "benchmark": "glass_transition_temperature",
      "label": "DMA transition temperature, after 2160 h UV ageing",
      "value": -37,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "material": "industrial EPDM housing with aluminium trihydrate filler, peroxide cured",
        "exposure": "UVA 340 nm, 45 °C, dry, 2160 h"
      },
      "method": "Temperature label on the tan delta plot in Fig. 3 legend",
      "status": "ground",
      "source": "bencherif-2019",
      "where": "Figure 3 legend (tan delta vs temperature), 2160 h (UV Aging)",
      "source_detail": {
        "title": "Multiscale Analysis of the Polymeric Insulators Degradation in Simulated Arid Environment Conditions: Cross-Correlation Assessment, Journal of Electrical Engineering and Technology",
        "id": "DOI 10.1007/s42835-019-00217-7",
        "url": "https://orbi.umons.ac.be/bitstream/20.500.12907/37612/1/Bencherif_et_al-2019-Journal_of_Electrical_Engineering__Technology.pdf",
        "year": 2019,
        "kind": "paper",
        "license": "Springer, cited"
      }
    },
    {
      "benchmark": "dtg_peak_temperature",
      "label": "TGA DTG peak temperature, new filled EPDM",
      "value": 365,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "atmosphere": "nitrogen",
        "heating_rate": "10 °C/min, 25 to 800 °C",
        "material": "industrial EPDM housing with aluminium trihydrate filler"
      },
      "method": "Thermogravimetric analysis, DTG peak temperature",
      "status": "ground",
      "source": "bencherif-2019",
      "where": "Table 3 TGA and DTG results summary, New row",
      "source_detail": {
        "title": "Multiscale Analysis of the Polymeric Insulators Degradation in Simulated Arid Environment Conditions: Cross-Correlation Assessment, Journal of Electrical Engineering and Technology",
        "id": "DOI 10.1007/s42835-019-00217-7",
        "url": "https://orbi.umons.ac.be/bitstream/20.500.12907/37612/1/Bencherif_et_al-2019-Journal_of_Electrical_Engineering__Technology.pdf",
        "year": 2019,
        "kind": "paper",
        "license": "Springer, cited"
      }
    },
    {
      "benchmark": "dtg_peak_temperature",
      "label": "TGA DTG peak temperature, after 2160 h UV ageing",
      "value": 354,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "atmosphere": "nitrogen",
        "heating_rate": "10 °C/min, 25 to 800 °C",
        "exposure": "UVA 340 nm, 45 °C, 2160 h"
      },
      "method": "Thermogravimetric analysis, DTG peak temperature",
      "status": "ground",
      "source": "bencherif-2019",
      "where": "Table 3 TGA and DTG results summary, 2160 h aged row",
      "source_detail": {
        "title": "Multiscale Analysis of the Polymeric Insulators Degradation in Simulated Arid Environment Conditions: Cross-Correlation Assessment, Journal of Electrical Engineering and Technology",
        "id": "DOI 10.1007/s42835-019-00217-7",
        "url": "https://orbi.umons.ac.be/bitstream/20.500.12907/37612/1/Bencherif_et_al-2019-Journal_of_Electrical_Engineering__Technology.pdf",
        "year": 2019,
        "kind": "paper",
        "license": "Springer, cited"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Hot air, 125 °C, 70 h (sulphur-cured 70 ShA)",
      "headline": "Hot air ageing hardens the sulphur-cured grade and removes some strength and elongation.",
      "effect": "After 70 h at 125 °C in air (ASTM D 573), hardness rose by 4 points, tensile strength fell 14% and ultimate elongation fell 24%.",
      "rating": "moderate",
      "conditions": {
        "time": "70 h",
        "temperature": "125 °C",
        "standard": "ASTM D 573"
      },
      "source": "polymax-sulphur",
      "where": "Aging property table, Air row"
    },
    {
      "environment": "Water, 100 °C, 70 h (sulphur-cured 70 ShA)",
      "headline": "Hot water swells the sulphur-cured grade slightly.",
      "effect": "After 70 h at 100 °C in water (ASTM D 471), volume rose by 2%.",
      "rating": "low",
      "conditions": {
        "time": "70 h",
        "temperature": "100 °C",
        "standard": "ASTM D 471"
      },
      "source": "polymax-sulphur",
      "where": "Aging property table, Water row"
    },
    {
      "environment": "Hot air, 150 °C, 70 h (peroxide-cured 70 ShA)",
      "headline": "The peroxide-cured grade holds up better in hot air, losing about a quarter of its strength and elongation.",
      "effect": "After 70 h at 150 °C in air (ISO 188 B), hardness rose by 4 points, tensile strength fell 25% and ultimate elongation fell 25%. Volume fell 0.4%.",
      "rating": "moderate",
      "conditions": {
        "time": "70 h",
        "temperature": "150 °C",
        "standard": "ISO 188 B"
      },
      "source": "polymax-peroxide",
      "where": "Aging property table, Air row"
    },
    {
      "environment": "Water, 100 °C, 70 h (peroxide-cured 70 ShA)",
      "headline": "Hot water barely changes the peroxide-cured grade.",
      "effect": "After 70 h at 100 °C in water (ISO 1817), hardness changed by -1 point, tensile strength by -4%, ultimate elongation by -7%, and volume rose by 1.3%.",
      "rating": "low",
      "conditions": {
        "time": "70 h",
        "temperature": "100 °C",
        "standard": "ISO 1817"
      },
      "source": "polymax-peroxide",
      "where": "Aging property table, Water row"
    },
    {
      "environment": "Heat, 100 °C, 70 h (EP70 compound, tested)",
      "headline": "The EP70 compound changes little after 70 h at 100 °C.",
      "effect": "After 70 h at 100 °C, hardness changed by +3 points, tensile strength by +1% and elongation by -9%.",
      "rating": "low",
      "conditions": {
        "time": "70 h",
        "temperature": "100 °C"
      },
      "source": "polymax-ep70",
      "where": "Heat Resistance Test row, tested column"
    },
    {
      "environment": "Steam at 288 °C (550 °F), 70 h, special ethylene propylene compound E0962-90",
      "headline": "A special EPDM compound shows little change after long steam exposure at 288 °C.",
      "effect": "Parker says compound E0962-90 showed very little change in physical properties after 70 hours exposure to steam at 288 °C (550 °F). Parker gives no number for ordinary compounds.",
      "rating": "low",
      "conditions": {
        "time": "70 h",
        "temperature": "288 °C",
        "compound": "E0962-90"
      },
      "source": "parker-handbook",
      "where": "Steam and water sealing text beside the Hot water and steam discussion (section number not read in this run)"
    },
    {
      "environment": "Petroleum lubricants in contact with the seal",
      "headline": "EPDM deteriorates in petroleum lubricants, a key limit for this rubber.",
      "effect": "Parker says that when sealing steam or water with ethylene propylene rubber, the seal will deteriorate when exposed to petroleum lubricants. Parker suggests silicone oil, glycerin or ethylene glycol when lubrication is required.",
      "rating": "severe",
      "conditions": {
        "basis": "qualitative statement, no test conditions given"
      },
      "source": "parker-handbook",
      "where": "Steam and water sealing text beside compound E0962-90 (section number not read in this run)"
    },
    {
      "environment": "UV weathering, UVA 340 nm at 45 °C, dry, up to 2160 h (filled EPDM housing)",
      "headline": "UV crosslinks and oxidises the filled EPDM, and its surface becomes less water-repellent.",
      "effect": "The paper reports a crosslinking process along weathering, oxygenated species that rise with time, and a surface contact angle that falls linearly with ageing time. The paper prints no contact-angle value. Its TGA showed no loss of thermal stability in the components. The lamps gave 0.89 W/m2/nm with no condensation, following the ASTM G154 approach the paper cites.",
      "rating": "moderate",
      "conditions": {
        "exposure": "UVA 340 nm, 45 °C, dry, up to 2160 h",
        "irradiance": "0.89 W/m2/nm",
        "material": "EPDM with aluminium trihydrate filler, peroxide cured"
      },
      "source": "bencherif-2019",
      "where": "Sections 2.2 and 4 (Conclusions)"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "No classification was found for the EPDM compound in this run. No EPDM safety data sheet was retrieved.",
        "ghs": [],
        "source": "polymax-sulphur",
        "where": "not found"
      },
      {
        "text": "Ethylene is an extremely flammable gas that may explode if heated, and may cause drowsiness or dizziness. This is for the monomer, not the EPDM compound.",
        "ghs": [
          "H220",
          "H280",
          "H336"
        ],
        "source": "pubchem-ethylene",
        "where": "GHS Classification (CID 6325), aggregated"
      },
      {
        "text": "Propylene is an extremely flammable gas and a gas under pressure that may explode if heated. This is for the monomer, not the EPDM compound.",
        "ghs": [
          "H220",
          "H280"
        ],
        "source": "pubchem-propylene",
        "where": "GHS Classification (CID 8252), aggregated"
      },
      {
        "text": "Ethylidene norbornene (the usual diene) is a flammable liquid that may be fatal if swallowed and enters airways. PubChem also lists skin and eye irritation, harm if inhaled, and an aquatic hazard. Percentages are PubChem's notification shares.",
        "ghs": [
          "H226",
          "H304",
          "H315",
          "H319",
          "H332",
          "H335",
          "H411"
        ],
        "source": "pubchem-enb",
        "where": "GHS Classification (CID 27756), aggregated"
      }
    ],
    "failure_risks": [
      {
        "mode": "Hardening and loss of elasticity after heat ageing",
        "trigger": "Service at 125 °C in air for 70 h (sulphur-cured grade)",
        "consequence": "Tensile strength falls 14% and elongation falls 24%, with a 4-point rise in hardness",
        "severity": "moderate",
        "source": "polymax-sulphur",
        "where": "Aging property table, Air row"
      },
      {
        "mode": "Permanent set after long compression at heat",
        "trigger": "Compressed for 22 h at 125 °C (sulphur-cured) or the same test on the EP70 compound",
        "consequence": "Set of 38% for the sulphur-cured grade, against 13% for the peroxide-cured and EP70 grades. The seal recovers less of its shape and may leak.",
        "severity": "moderate",
        "source": "polymax-sulphur",
        "where": "Physical property table, Compression Set row"
      },
      {
        "mode": "Deterioration in petroleum lubricants",
        "trigger": "Seal in contact with petroleum lubricants, or lubricated with them",
        "consequence": "Parker says EPDM deteriorates when exposed to petroleum lubricants; use silicone oil, glycerin or ethylene glycol instead",
        "severity": "critical",
        "source": "parker-handbook",
        "where": "Steam and water sealing text beside compound E0962-90 (section number not read in this run)"
      },
      {
        "mode": "Stiffening below the low-temperature limit",
        "trigger": "Operation below -30 °C (sulphur-cured) or -42 °C (peroxide-cured, ISO 2921)",
        "consequence": "The seal loses flexibility and may leak",
        "severity": "moderate",
        "source": "polymax-peroxide",
        "where": "Operating temperature range line and Low Temperature Resistance row"
      },
      {
        "mode": "Compression set after gamma dose",
        "trigger": "10^7 rad gamma at room temperature",
        "consequence": "E0740-75 takes a 28.6% set and E0515-80 a 46.6% set, which lowers the seal's recovery",
        "severity": "moderate",
        "source": "parker-handbook",
        "where": "Section 3.9.14 Radiation, Data on Radiation Resistant Compounds table"
      },
      {
        "mode": "UV photo-oxidation",
        "trigger": "UVA 340 nm at 45 °C, dry, for up to 2160 h",
        "consequence": "Crosslinking and oxygenated species form, and the surface becomes less water-repellent. The transition temperature moves from -42 °C to -37 °C.",
        "severity": "moderate",
        "source": "bencherif-2019",
        "where": "Sections 2.2 and 4 (Conclusions); Figure 3 legend"
      }
    ],
    "side_effects": [
      {
        "text": "No side effects found in this run.",
        "affects": "Not sourced",
        "source": "parker-handbook",
        "where": "not found"
      }
    ],
    "handling": [
      {
        "text": "Read the safety data sheet for the specific EPDM compound before use. None was retrieved in this run.",
        "source": "polymax-sulphur",
        "where": "not found"
      },
      {
        "text": "Keep ethylene and propylene gases away from heat. PubChem's H280 says they may explode if heated.",
        "source": "pubchem-ethylene",
        "where": "GHS H280 statement (CID 6325)"
      },
      {
        "text": "Do not lubricate EPDM seals with petroleum lubricants. Parker suggests silicone oil, glycerin or ethylene glycol.",
        "source": "parker-handbook",
        "where": "Steam and water sealing text beside compound E0962-90"
      }
    ],
    "mitigations": [
      {
        "text": "Choose a peroxide-cured compound for service up to 150 °C. Polymax rates the sulphur-cured grade to 120 °C in its text, and its operating range line says 125 °C.",
        "source": "polymax-peroxide",
        "where": "Description paragraph and operating temperature range line"
      },
      {
        "text": "Lubricate with silicone oil, glycerin or ethylene glycol rather than petroleum lubricants.",
        "source": "parker-handbook",
        "where": "Steam and water sealing text beside compound E0962-90"
      }
    ]
  },
  "uses": [
    {
      "application": "mechanisms",
      "device": "O-ring seals in brake systems that use glycol (DOT 3 and 4) or silicone (DOT 5) fluids",
      "example": "Polymax says EPDM is particularly useful when sealing in brake systems that use glycol or silicone based fluids. Parker says EPDM is particularly useful in phosphate-ester hydraulic fluids and in brake systems that use glycol bases. No space mission was named.",
      "source": "polymax-sulphur",
      "where": "Description paragraph"
    },
    {
      "application": "mechanisms",
      "device": "O-rings and gaskets in vacuum equipment, tested to the ASTM E 595 outgassing method",
      "example": "NASA's outgassing database lists EPDM O-rings and gaskets tested to ASTM E 595, with total mass loss and volatile condensable results per part. The values are not recorded in this file (see gaps). No spacecraft flight use was named in the sources read.",
      "source": "nasa-outgassing",
      "where": "Database rows GSFC36138, GSFC34174, GFC37364, GSFC36351"
    }
  ],
  "supply": [
    {
      "subject": "Sulphur, the curing agent for sulphur-cured EPDM",
      "abundance": "World sulphur production was 83,900 thousand t in 2024 and 84,000 thousand t in 2025 (USGS). China produced 19,000 thousand t in both years. Most sulphur is recovered from petroleum and natural gas processing.",
      "producers": [],
      "critical_lists": [],
      "recycling": "Not stated in the USGS summary read here.",
      "substitutes": [],
      "source": "usgs-sulfur",
      "where": "World Production and Reserves table; Domestic Production and Use"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Polymax EPDM 70 ShA sulphur-cured O-ring datasheet",
      "type": "datasheet",
      "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_oring_polymax.pdf"
    },
    {
      "title": "Polymax EPDM 70 ShA peroxide-cured O-ring datasheet",
      "type": "datasheet",
      "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_peroxide_oring_polymax.pdf"
    },
    {
      "title": "Polymax EP70 EPDM technical data sheet",
      "type": "datasheet",
      "url": "https://www.polymax.co.uk//media/documents/Datasheet/ORing_EPDM-70.pdf"
    },
    {
      "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
      "type": "report",
      "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
      "year": 2022
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026, sulfur",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-sulfur.pdf",
      "year": 2026
    },
    {
      "title": "NASA Goddard outgassing database (ASTM E 595 results)",
      "type": "database",
      "url": "https://etd.gsfc.nasa.gov/capabilities/outgassing-database/"
    },
    {
      "title": "Multiscale analysis of polymeric insulator degradation in simulated arid conditions (EPDM UV ageing)",
      "type": "paper",
      "url": "https://orbi.umons.ac.be/bitstream/20.500.12907/37612/1/Bencherif_et_al-2019-Journal_of_Electrical_Engineering__Technology.pdf",
      "year": 2019
    }
  ],
  "gaps": [
    "Ethylene and propylene production shares by country, and EPDM producer shares, were not found in a source read in this run. Market-research summaries conflicted with each other and were not used.",
    "Feedstock source for ethylene, propylene and the diene (natural gas or oil refining) is not stated in any source read here.",
    "Monomer ratio, ethylene content and the diene used in the Polymax grades are not printed in any source read. Wikipedia gives a diene content of 2 to 12% but no ethylene figure.",
    "The NASA outgassing database loads its table by script. EPDM rows (total mass loss, CVCM and WVR under ASTM E 595) were read from the rendered table in this run, but the static page the value check fetches does not print them, so no outgassing value is recorded in this file. Re-check the database directly before adding them. Rows are per part from several manufacturers, not one grade, and its shorthand test codes (for example E-2, E-4) are not decoded.",
    "NASA RP-1124 Revision 4 was read in this run and contains no EPDM entry. The online database above replaces it.",
    "Atomic oxygen erosion of EPDM was searched for in this run and not found. Nothing on EPDM in low Earth orbit is recorded here.",
    "Parker vacuum weight loss is recorded under the benchmark name vacuum_weight_loss, which is not in property-canon.yaml. Other non-canonical names: compression_set, hardness, tear_strength, dtg_peak_temperature.",
    "Ultraviolet ageing data come from one paper on a filled, peroxide-cured housing. No UV data for unfilled EPDM were found, and no humidity ageing beyond the 70 h water tests on the Polymax datasheets.",
    "Parker's Good ratings for steam and water in the radiation table are words, not numbers, and were not used as values.",
    "Hazard data for the EPDM compound itself: no safety data sheet was retrieved in this run. PubChem gives the monomers only.",
    "Designations: the Polymax ASTM D2000 line codes (for example M5 CA710 A15 B35) belong to specific Polymax grades, not to EPDM in general, and are not listed. The only general designation read is ASTM D1418 M-class, from Wikipedia.",
    "Amine, nitrogen tetroxide and other liquid rocket propellant compatibility of EPDM were not searched in this run.",
    "Producers of EPDM (Lanxess Arlanxeo, ExxonMobil, Dow, Kumho and others) are named in market-research summaries only, and no company page was read.",
    "Polymax E70 datasheet is hosted on a development domain (m2dev.polymax.co.uk) and was not used.",
    "Wikipedia's property table (maximum service temperature 150 °C, minimum -50 °C, glass transition -54 °C) carries a citation-needed tag and was not used as a value."
  ],
  "story": {
    "why": "EPDM is a rubber that stays elastic in hot water, steam and weather. Parker's handbook gives it up to 150 °C in water and steam and cold flexibility to about -57 °C, and says it is particularly useful in glycol and silicone brake fluids. It is weak in petroleum lubricants, which Parker says it deteriorates in.",
    "uses": [
      {
        "where": "O-ring seals in brake systems",
        "line": "Polymax says EPDM is particularly useful in brake systems with glycol (DOT 3 and 4) or silicone (DOT 5) fluids. Parker says it is useful with phosphate-ester hydraulic fluids."
      },
      {
        "where": "Vacuum equipment O-rings and gaskets",
        "line": "NASA's outgassing database lists EPDM O-rings and gaskets tested to ASTM E 595. Their values are not recorded in this file (see gaps). No spacecraft flight use was named."
      }
    ],
    "can_do": [
      {
        "label": "Temperature",
        "line": "Polymax gives -30 to 125 °C for the sulphur-cured 70 ShA grade and -30 to 150 °C for the peroxide-cured grade. Parker gives up to 150 °C in water and steam, with special compounds to 260 °C in hot water and steam.",
        "scope": "material",
        "value": "-30 to 150 °C"
      },
      {
        "label": "Cold",
        "line": "Parker gives cold flexibility down to about -57 °C. The peroxide-cured Polymax grade is rated to -42 °C by ISO 2921.",
        "scope": "material",
        "value": "-57 °C"
      },
      {
        "label": "Hardness and strength",
        "line": "The 70 Shore A grades have a tensile strength of 10.5 to 17 MPa and an elongation of 220 to 255%.",
        "scope": "material",
        "value": "70 to 71 Shore A"
      },
      {
        "label": "Compression set",
        "line": "The peroxide-cured and EP70 grades keep 13% set after the test. The sulphur-cured grade keeps 38% after 22 h at 125 °C (ASTM D 395 B).",
        "scope": "material",
        "value": "13 to 38%"
      },
      {
        "label": "Outgassing",
        "line": "NASA's database rows for EPDM O-rings differ before and after bakeout, and between manufacturers. The values are not recorded in this file because the database page loads them by script (see gaps).",
        "scope": "material",
        "value": "Depends on part and bakeout"
      }
    ],
    "compare": "EPDM is a general-purpose elastomer for hot water, steam, ozone and brake-fluid seals. Its best service is in water and steam, where Parker says ethylene propylene is generally superior to fluorocarbon. It is cold-flexible, but Parker says it deteriorates in petroleum lubricants. No comparison table with other elastomers was built in this run.",
    "compare_rows": [
      {
        "label": "Operating range, upper limit",
        "benchmark": "max_service_temp",
        "scope": "material"
      },
      {
        "label": "Low-temperature limit",
        "benchmark": "min_service_temp",
        "scope": "material"
      },
      {
        "label": "Compression set",
        "benchmark": "compression_set",
        "scope": "material"
      }
    ],
    "handling": [
      "Read the product safety data sheet before use. None was retrieved in this run.",
      "Do not lubricate with petroleum lubricants. Use silicone oil, glycerin or ethylene glycol, as Parker suggests.",
      "Keep ethylene and propylene gases away from heat, since PubChem's H280 says they may explode if heated."
    ],
    "good_for": [
      "Hot water, steam and weathering seals, and brake-fluid seals in glycol or silicone fluids (Polymax and Parker).",
      "Vacuum seals after bakeout: NASA's database has ASTM E 595 rows for EPDM O-rings, and the rows differ before and after bakeout (values not recorded here, see gaps).",
      "Cold flexibility down to about -57 °C (Parker)."
    ],
    "watch_out": [
      "Petroleum lubricants and oils: Parker says EPDM deteriorates in them.",
      "Heat ageing: 14% tensile loss and 24% elongation loss after 70 h at 125 °C (sulphur-cured grade).",
      "Compression set rises with heat: 38% after 22 h at 125 °C for the sulphur-cured grade, against 13% for the peroxide-cured grade.",
      "UV: a filled, peroxide-cured housing crosslinks and oxidises under UVA and its transition temperature moves from -42 °C to -37 °C after 2160 h.",
      "Radiation: at 10^7 rad, E0515-80 takes a 46.6% set (Parker)."
    ],
    "verdict": "EPDM is a dependable seal for hot water, steam, ozone and brake-fluid service. It does poorly in petroleum oils and lubricants, and its vacuum outgassing depends on the part and bakeout, so each seal needs a test or a verified NASA database row.",
    "recipe": {
      "line": "EPDM is a terpolymer of ethylene, propylene and a diene. The diene (ethylidene norbornene, dicyclopentadiene or vinyl norbornene, about 2 to 12% in commercial grades per Wikipedia) carries the cure sites, so the rubber crosslinks by sulphur vulcanisation or by peroxide. Commercial compounds are filled with carbon black or mineral filler and extended with plasticisers. The UV-aged study used an aluminium trihydrate filled, peroxide-cured compound.",
      "parts": [
        {
          "name": "Ethylene",
          "role": "Main monomer; with propylene it forms the saturated polyethylene-type backbone."
        },
        {
          "name": "Propylene",
          "role": "Second main monomer; it breaks up the polyethylene crystallinity so the rubber stays elastic."
        },
        {
          "name": "Diene",
          "role": "Cure site. Its double bonds take part in sulphur or peroxide crosslinking."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "No hazard classification was retrieved for the EPDM compound in this run.",
        "points": [
          {
            "label": "Safety data",
            "line": "Read the safety data sheet for the specific compound before handling. None was retrieved here."
          }
        ]
      },
      {
        "title": "For the monomers",
        "lead": "PubChem classifies the monomers, not the compound. Ethylene and propylene are extremely flammable gases under pressure. Ethylidene norbornene is a flammable liquid.",
        "points": [
          {
            "label": "Ethylene",
            "line": "Extremely flammable gas, which may explode if heated. PubChem also lists drowsiness or dizziness (H336)."
          },
          {
            "label": "Propylene",
            "line": "Extremely flammable gas under pressure. PubChem lists the same H220 and H280 codes as ethylene."
          },
          {
            "label": "Ethylidene norbornene",
            "line": "Flammable liquid that may be fatal if swallowed and enters airways. PubChem also lists harm if inhaled and possible skin and eye irritation."
          }
        ],
        "verdict": "Flammable gases, and a flammable liquid diene"
      }
    ]
  },
  "updated": "2026-10-26",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 36,
    "unreachable": 0,
    "caveats": 0,
    "note": "Written on 2026-10-26 from Parker O-Ring Handbook, Polymax datasheets (sulphur, peroxide, EP70), USGS sulfur 2026, PubChem GHS for ethylene, propylene and ethylidenenorbornene, Wikipedia EPDM and the Bencherif 2019 UV ageing paper, all read in this run. NASA outgassing rows were read from the rendered database but are not recorded as values."
  },
  "sources": {
    "parker-handbook": {
      "title": "Parker O-Ring Handbook (copy hosted by the University of Arizona)",
      "id": "Parker O-Ring Handbook, copy at the University of Arizona",
      "url": "https://nfc.arizona.edu/sites/default/files/2022-02/parker_o-ring_handbook.pdf",
      "year": 2022,
      "kind": "handbook",
      "license": "Manufacturer handbook, cited"
    },
    "polymax-sulphur": {
      "title": "EPDM 70 ShA sulphur-cured O-ring datasheet, Polymax",
      "id": "Polymax datasheet epdm_70sha_oring",
      "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_oring_polymax.pdf",
      "kind": "datasheet",
      "license": "Supplier datasheet, cited"
    },
    "polymax-peroxide": {
      "title": "EPDM 70 ShA peroxide-cured O-ring datasheet, Polymax",
      "id": "Polymax datasheet epdm_70sha_peroxide_oring",
      "url": "https://www.polymax.co.uk/media/documents/Datasheet/epdm_70sha_peroxide_oring_polymax.pdf",
      "kind": "datasheet",
      "license": "Supplier datasheet, cited"
    },
    "polymax-ep70": {
      "title": "EP70 EPDM technical data sheet, Polymax",
      "id": "Polymax technical data sheet ORing_EPDM-70",
      "url": "https://www.polymax.co.uk//media/documents/Datasheet/ORing_EPDM-70.pdf",
      "kind": "datasheet",
      "license": "Supplier datasheet, cited"
    },
    "nasa-outgassing": {
      "title": "NASA Goddard outgassing database, EPDM rows",
      "id": "NASA GSFC outgassing database, Material filter EPDM",
      "url": "https://etd.gsfc.nasa.gov/capabilities/outgassing-database/",
      "kind": "database",
      "license": "NASA public data"
    },
    "usgs-sulfur": {
      "title": "Mineral Commodity Summaries 2026, Sulfur, U.S. Geological Survey",
      "id": "USGS MCS 2026, sulfur",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-sulfur.pdf",
      "year": 2026,
      "kind": "report",
      "license": "U.S. Government work, public domain"
    },
    "pubchem-ethylene": {
      "title": "PubChem, Ethylene (CID 6325)",
      "id": "PubChem CID 6325",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/6325",
      "kind": "database",
      "license": "PubChem, public database"
    },
    "pubchem-propylene": {
      "title": "PubChem, Propylene (CID 8252)",
      "id": "PubChem CID 8252",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/8252",
      "kind": "database",
      "license": "PubChem, public database"
    },
    "pubchem-enb": {
      "title": "PubChem, Ethylidenenorbornene (CID 27756)",
      "id": "PubChem CID 27756",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/27756",
      "kind": "database",
      "license": "PubChem, public database"
    },
    "wikipedia-epdm": {
      "title": "Wikipedia, EPDM rubber",
      "id": "Wikipedia EPDM rubber; composition and classification only",
      "url": "https://en.wikipedia.org/wiki/EPDM_rubber",
      "kind": "web",
      "license": "CC BY-SA 4.0"
    },
    "bencherif-2019": {
      "title": "Multiscale Analysis of the Polymeric Insulators Degradation in Simulated Arid Environment Conditions: Cross-Correlation Assessment, Journal of Electrical Engineering and Technology",
      "id": "DOI 10.1007/s42835-019-00217-7",
      "url": "https://orbi.umons.ac.be/bitstream/20.500.12907/37612/1/Bencherif_et_al-2019-Journal_of_Electrical_Engineering__Technology.pdf",
      "year": 2019,
      "kind": "paper",
      "license": "Springer, cited"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/epdm/"
}