{
  "spore": "profile",
  "id": "polyethylene",
  "spore_version": "0.2",
  "family": "polyolefins",
  "name": "Polyethylene",
  "abbreviation": "PE",
  "role": "lithium-ion separator polymer and general engineering thermoplastic",
  "category": "polymers",
  "type": "polyolefins",
  "summary": "Polyethylene is the ethylene polymer used as the shutdown layer of lithium-ion battery separators and as a general engineering plastic. A general-purpose virgin HDPE injection grade (H5818J) has a density of 0.959 g/cm3 and a tensile strength at yield of 290 kg/cm2. A PE-UHMW grade (Braskem Utec 3041) lists a density of 925 kg/m3, a tensile strength at yield of 17 MPa and an elongation at break of 400 %. A polyethylene microporous separator is stated to shut down, closing its pores, around 130 °C.\n",
  "best_for": "Low-density, tough, chemically resistant plastic, and a melt-based shutdown near 130 °C in a battery separator",
  "weakest_at": "Stiffness and heat resistance: a separator layer melts near 130 to 135 °C, and the H5818J HDPE grade has a flexural modulus of 13000 kg/cm2",
  "identity": {
    "formula": "(C2H4)n, polymer of ethylene",
    "cas": "9002-88-4",
    "designations": [],
    "source": "scg-h5818j",
    "where": "Product page for grade H5818J, which describes it as a high density polyethylene resin (HDPE). CAS number 9002-88-4 is printed in Sections 1 and 3 of the SDS listed as chemicalbook-pe-sds."
  },
  "tags": {
    "environments": [
      "low-earth-orbit"
    ],
    "stresses": [
      "thermal-cycling",
      "extreme-heat"
    ],
    "applications": [
      "batteries",
      "structures",
      "thermal-control"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, general-purpose HDPE injection grade H5818J",
      "value": 0.959,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "H5818J (HDPE, general purpose, injection molding)",
        "temperature": "not stated"
      },
      "method": "ASTM D 1505, as printed in a manufacturer product page",
      "status": "ground",
      "source": "scg-h5818j",
      "where": "Physical table, row Density",
      "source_detail": {
        "title": "SCG Chemicals product grade page, H5818J general purpose HDPE for injection molding",
        "url": "https://www.scgchemicals.com/en/products-grade/h5818j",
        "kind": "datasheet",
        "license": "Manufacturer product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Tensile strength at yield, HDPE injection grade H5818J",
      "value": 290,
      "bound": "exact",
      "unit": "kg/cm2",
      "scope": "material",
      "conditions": {
        "grade": "H5818J (HDPE, injection molding)",
        "test_speed": "crosshead 50 mm/min",
        "unit_in_source": "kg/cm2"
      },
      "method": "ASTM D 638, as printed in a manufacturer product page",
      "status": "ground",
      "note": "The page gives the value in kg/cm2 and does not convert it; 290 kg/cm2 is about 28 MPa.",
      "source": "scg-h5818j",
      "where": "Mechanical table, row Tensile Strength at Yield",
      "source_detail": {
        "title": "SCG Chemicals product grade page, H5818J general purpose HDPE for injection molding",
        "url": "https://www.scgchemicals.com/en/products-grade/h5818j",
        "kind": "datasheet",
        "license": "Manufacturer product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Flexural modulus, HDPE injection grade H5818J (flexural, not tensile)",
      "value": 13000,
      "bound": "exact",
      "unit": "kg/cm2",
      "scope": "material",
      "conditions": {
        "grade": "H5818J (HDPE, injection molding)",
        "temperature": "not stated"
      },
      "method": "ASTM D 790, as printed in a manufacturer product page",
      "status": "ground",
      "source": "scg-h5818j",
      "where": "Mechanical table, row Flexural Modulus",
      "source_detail": {
        "title": "SCG Chemicals product grade page, H5818J general purpose HDPE for injection molding",
        "url": "https://www.scgchemicals.com/en/products-grade/h5818j",
        "kind": "datasheet",
        "license": "Manufacturer product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, recycled-content HDPE (Recythen)",
      "value": 950,
      "bound": "exact",
      "unit": "kg/m3",
      "scope": "material",
      "conditions": {
        "grade": "Recythen HDPE (product name suggests recycled resin; the page does not state the recycled content)",
        "temperature": "not stated"
      },
      "method": "ISO 1183, as printed in a supplier data sheet",
      "status": "ground",
      "source": "recythen-hdpe",
      "where": "Other properties table, row Density",
      "source_detail": {
        "title": "Recythen HDPE, Interseroh Dienstleistungs GmbH, material data center entry",
        "url": "https://materialdatacenter.com/ms/en/Recythen/Interseroh+Dienstleistungs+GmbH/recythen®+HDPE/b74b37cd/6918",
        "kind": "datasheet",
        "license": "Supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, recycled HDPE (Recythen), ISO 527",
      "value": 21,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Recythen HDPE",
        "test_condition": "none listed on the page",
        "note_in_source": "page does not say whether this is yield or break"
      },
      "method": "ISO 527, as printed in a supplier data sheet",
      "status": "ground",
      "source": "recythen-hdpe",
      "where": "Mechanical properties table, row Tensile Strength",
      "source_detail": {
        "title": "Recythen HDPE, Interseroh Dienstleistungs GmbH, material data center entry",
        "url": "https://materialdatacenter.com/ms/en/Recythen/Interseroh+Dienstleistungs+GmbH/recythen®+HDPE/b74b37cd/6918",
        "kind": "datasheet",
        "license": "Supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Tensile modulus, recycled HDPE (Recythen), ISO 527",
      "value": 800,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Recythen HDPE",
        "test_condition": "none listed on the page"
      },
      "method": "ISO 527, as printed in a supplier data sheet",
      "status": "ground",
      "source": "recythen-hdpe",
      "where": "Mechanical properties table, row Tensile Modulus",
      "source_detail": {
        "title": "Recythen HDPE, Interseroh Dienstleistungs GmbH, material data center entry",
        "url": "https://materialdatacenter.com/ms/en/Recythen/Interseroh+Dienstleistungs+GmbH/recythen®+HDPE/b74b37cd/6918",
        "kind": "datasheet",
        "license": "Supplier data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting temperature, HDPE pipe grade (ASTM D3418)",
      "value": 128,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "HDPE pipe grade table (grade name not printed in the extracted table)",
        "test": "ASTM D3418 as printed"
      },
      "method": "Value printed in a supplier data table",
      "status": "ground",
      "note": "The table was flattened during extraction, so the mapping of values to grades is taken from the table headings; check the original page before relying on it.",
      "source": "pertachem-hdpe",
      "where": "HDPE PIPE grade table, row Melting Temperature. The table's other pipe-grade values look inconsistent, so only this melting temperature is kept.",
      "source_detail": {
        "title": "Pertachem, HDPE product table",
        "url": "https://pertachem.com/hdpe-en",
        "kind": "datasheet",
        "license": "Supplier web page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, PE-UHMW grade Utec 3041",
      "value": 925,
      "bound": "exact",
      "unit": "kg/m3",
      "scope": "material",
      "conditions": {
        "grade": "Utec 3041 (PE-UHMW, Braskem)",
        "temperature": "not stated"
      },
      "method": "ASTM D 792, as printed in a manufacturer data sheet (via Material Data Center)",
      "status": "ground",
      "source": "utec-3041",
      "where": "Other properties table, row Density",
      "source_detail": {
        "title": "Braskem Utec 3041 PE-UHMW data sheet, Material Data Center entry",
        "url": "https://materialdatacenter.com/ms/en/Utec/Braskem/Utec®+3041/7517bb03/487",
        "kind": "datasheet",
        "license": "Manufacturer data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Tensile strength at yield, PE-UHMW grade Utec 3041",
      "value": 17,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Utec 3041 (PE-UHMW, Braskem)",
        "test": "ISO 527",
        "temperature": "not stated"
      },
      "method": "ISO 527, as printed in a manufacturer data sheet (via Material Data Center)",
      "status": "ground",
      "source": "utec-3041",
      "where": "Mechanical properties, ISO Data, row Yield stress",
      "source_detail": {
        "title": "Braskem Utec 3041 PE-UHMW data sheet, Material Data Center entry",
        "url": "https://materialdatacenter.com/ms/en/Utec/Braskem/Utec®+3041/7517bb03/487",
        "kind": "datasheet",
        "license": "Manufacturer data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength at break, PE-UHMW grade Utec 3041",
      "value": 30,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Utec 3041 (PE-UHMW, Braskem)",
        "test": "ISO 527",
        "temperature": "not stated"
      },
      "method": "ISO 527, as printed in a manufacturer data sheet (via Material Data Center)",
      "status": "ground",
      "source": "utec-3041",
      "where": "Mechanical properties, ISO Data, row Stress at break",
      "source_detail": {
        "title": "Braskem Utec 3041 PE-UHMW data sheet, Material Data Center entry",
        "url": "https://materialdatacenter.com/ms/en/Utec/Braskem/Utec®+3041/7517bb03/487",
        "kind": "datasheet",
        "license": "Manufacturer data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break, PE-UHMW grade Utec 3041",
      "value": 400,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "grade": "Utec 3041 (PE-UHMW, Braskem)",
        "test": "ISO 527",
        "temperature": "not stated"
      },
      "method": "ISO 527, as printed in a manufacturer data sheet (via Material Data Center)",
      "status": "ground",
      "source": "utec-3041",
      "where": "Mechanical properties, ISO Data, row Strain at break",
      "source_detail": {
        "title": "Braskem Utec 3041 PE-UHMW data sheet, Material Data Center entry",
        "url": "https://materialdatacenter.com/ms/en/Utec/Braskem/Utec®+3041/7517bb03/487",
        "kind": "datasheet",
        "license": "Manufacturer data sheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Thermal shutdown temperature of a polyethylene microporous battery separator (approximate)",
      "value": 130,
      "bound": "upper",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "membrane": "polyethylene microporous separator for lithium-ion cells",
        "basis": "approximate; the patent says the shutdown should occur at a temperature of less than 130 °C"
      },
      "method": "Value stated in the background and detailed description of a patent",
      "status": "ground",
      "source": "patent-us6749961",
      "where": "Background of the Invention (around 130 °C); Detailed Description (less than 130 °C)",
      "source_detail": {
        "title": "US 6,749,961 B1, Shutdown battery separator made with a blend of polymer and oligomer",
        "url": "https://patents.google.com/patent/US6749961",
        "kind": "web",
        "license": "Patent text (public record)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point of the PE layer of a PP/PE/PP separator",
      "value": 135,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "layer": "PE layer of a tri-layer PP/PE/PP separator",
        "note_in_source": "PP layer given as 165 °C in the same article"
      },
      "method": "Value stated in an industry article; no measurement described",
      "status": "ground",
      "source": "volta-separators",
      "where": "Section on tri-layer separators and the abuse-event paragraph",
      "source_detail": {
        "title": "Lithium-ion Battery Separators and their Role in Safety, Volta Foundation",
        "url": "https://volta.foundation/lithium-ion-battery-separators-and-their-role-in-safety/",
        "kind": "web",
        "license": "Web article (cited, not reproduced)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Ultraviolet light",
      "headline": "UHMWPE is described as very resistant to UV radiation; ordinary polyethylene yellows as it ages.",
      "effect": "Wikipedia's UHMWPE article says the material is very resistant to water, moisture, most chemicals, UV radiation and micro-organisms. The Polyethylene article says polyethylene yellows as it ages, without a mechanism or a dose. No UV exposure time or retained property was read in a fetched page.",
      "rating": "unknown",
      "conditions": {
        "basis": "qualitative statements only"
      },
      "source": "wiki-uhmwpe",
      "where": "Properties section; Polyethylene article, ageing sentence"
    },
    {
      "environment": "Oxidation (gentle oxidants and reducing agents)",
      "headline": "Most LDPE, MDPE and HDPE grades resist gentle oxidants; oxidation-stabilised UHMWPE is more resistant.",
      "effect": "Wikipedia says most LDPE, MDPE and HDPE grades are resistant to gentle oxidants and reducing agents. For UHMWPE it says vitamin E stabilisation gives improved oxidation resistance without thermal treatment, and that the Hylamer variant showed susceptibility to oxidation.",
      "rating": "low",
      "conditions": {
        "basis": "qualitative statements; no test standard or time printed"
      },
      "source": "wiki-polyethylene",
      "where": "Chemical resistance section"
    },
    {
      "environment": "Environmental stress cracking (ESC) in stress-cracking agents",
      "headline": "Semi-crystalline polyethylene can fail by brittle cracking under stress in stress-cracking agents; molar mass and tie molecules control resistance.",
      "effect": "Wikipedia says semi-crystalline polymers such as polyethylene show brittle fracture under stress in stress-cracking agents. The early LDPE ESC problem was solved by raising molecular weight, and ESC resistance is controlled by the number of tie molecules and the strength of the crystals that anchor them. Named tests include the Bell Telephone test, the Bergen jig, an Igepal detergent test, and a test said to match ASTM D1693 on a shorter time scale. The article says LLDPE films can have better ESC resistance than LDPE.",
      "rating": "moderate",
      "conditions": {
        "basis": "qualitative; no stress level, agent or time printed"
      },
      "source": "wiki-esc",
      "where": "Polyethylene section; Named tests section"
    },
    {
      "environment": "Strong acids, strong bases and most chemicals",
      "headline": "Polyethylene grades resist strong acids and bases; UHMWPE resists most chemicals except some oxidising acids.",
      "effect": "Wikipedia says most LDPE, MDPE and HDPE grades have excellent chemical resistance and are not attacked by strong acids or strong bases. For UHMWPE it says resistance to acids, alkalis and many corrosive chemicals, except some oxidising acids. No concentration or temperature is printed.",
      "rating": "low",
      "conditions": {
        "basis": "qualitative statements"
      },
      "source": "wiki-uhmwpe",
      "where": "Properties section (chemical resistance)"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "The ChemicalBook polyethylene SDS prints no signal word and no hazard statements in Section 2 (Hazards identification). Section 9 gives a flash point of 270 °C and lists auto-ignition temperature as no data available.",
        "ghs": [],
        "source": "chemicalbook-pe-sds",
        "where": "Sections 2 and 9"
      }
    ],
    "failure_risks": [
      {
        "mode": "Shutdown of the separator at its polyethylene melting point",
        "trigger": "Cell temperature reaching about 130 °C",
        "consequence": "The PE layer closes the pores and stops ion flow. The patent describes this as the intended shutdown. The article says the higher-melting PP layer of a tri-layer separator stays solid.",
        "severity": "moderate",
        "source": "volta-separators",
        "where": "Section on tri-layer separators and the abuse-event paragraph"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "Dry the pellets before processing: the Recythen data sheet gives a pre-drying temperature of 80 °C for 2 to 3 h, and a processing humidity of 0.15 % or less, for injection molding and extrusion.",
        "source": "recythen-hdpe",
        "where": "Processing recommendations table"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "batteries",
      "device": "Microporous separator between the electrodes of a lithium-ion cell",
      "example": "The patent describes a shutdown separator 'typically used in lithium ion rechargeable cells', made of polyethylene.",
      "source": "patent-us6749961",
      "where": "Background of the Invention"
    },
    {
      "application": "structures",
      "device": "Injection-molded plastic parts",
      "example": "H5818J is described as a general purpose HDPE resin suitable for injection molding.",
      "source": "scg-h5818j",
      "where": "Product description"
    }
  ],
  "supply": [
    {
      "subject": "Polyethylene",
      "abundance": "not searched",
      "producers": [],
      "critical_lists": [],
      "recycling": "The Recythen data sheet names a recycled-content HDPE grade, but gives no recycled percentage.",
      "substitutes": [],
      "source": "recythen-hdpe",
      "where": "Product name and certifications section"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Product page, SCG Chemicals grade H5818J (general purpose HDPE, injection molding)",
      "type": "datasheet",
      "url": "https://www.scgchemicals.com/en/products-grade/h5818j"
    },
    {
      "title": "Recythen HDPE data sheet (Interseroh), material data center entry",
      "type": "datasheet",
      "url": "https://materialdatacenter.com/ms/en/Recythen/Interseroh+Dienstleistungs+GmbH/recythen®+HDPE/b74b37cd/6918"
    },
    {
      "title": "Pertachem HDPE product table (pipe grade and other grades)",
      "type": "datasheet",
      "url": "https://pertachem.com/hdpe-en"
    },
    {
      "title": "Braskem Utec 3041 PE-UHMW data sheet (via Material Data Center)",
      "type": "datasheet",
      "url": "https://materialdatacenter.com/ms/en/Utec/Braskem/Utec®+3041/7517bb03/487"
    },
    {
      "title": "ChemicalBook polyethylene MSDS, CAS 9002-88-4 (reseller-hosted SDS page)",
      "type": "sds",
      "url": "https://www.chemicalbook.com/msds/polyethylene.htm"
    },
    {
      "title": "US 6,749,961 B1, Shutdown battery separator made with a blend of polymer and oligomer",
      "type": "database",
      "url": "https://patents.google.com/patent/US6749961"
    },
    {
      "title": "Lithium-ion battery separators and their role in safety (Volta Foundation article)",
      "type": "report",
      "url": "https://volta.foundation/lithium-ion-battery-separators-and-their-role-in-safety/"
    },
    {
      "title": "Celgard 2325 25 um trilayer PP/PE/PP separator roll (reseller listing, read but not used for numbers)",
      "type": "datasheet",
      "url": "https://cambridge-energy-solutions-ltd.odoo.com/shop/celgard-2325-25um-trilayer-pp-pe-pp-separator-roll-1757"
    },
    {
      "title": "NIST Atomic Weights and Isotopic Compositions",
      "type": "database",
      "url": "https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&ascii=html",
      "year": 2026
    }
  ],
  "gaps": [
    "Manufacturer SDS PDFs for polyethylene (NIST 2886 and others) returned unreadable binary; the CAS number and hazard data come from a reseller-hosted ChemicalBook SDS page.",
    "Atomic oxygen erosion yield of polyethylene on LDEF (about 3.97e-24 cm3/atom in a search snippet) was not read in a fetched page, so it is not entered.",
    "Celgard 2325 (PP/PE/PP trilayer) porosity 39 %, puncture 360 g and Gurley 620 s are on a reseller listing only; no manufacturer sheet was read, and the trilayer is not pure polyethylene, so they are not entered.",
    "Celanese GUR, TIVAR and Ensinger/IGEPA PE-UHMW datasheets were PDFs that returned no readable text; the UHMW values come from the Braskem Utec 3041 page on Material Data Center. No modulus or service temperature for Utec 3041 was printed on that page, so none is entered.",
    "Melt flow index for the H5818J grade (18 g/10 min at 190 °C, 2.16 kg, ASTM D1238) is printed on the SCG page but has no matching benchmark, so it is not entered.",
    "Radiation, outgassing (TML/CVCM), and atomic oxygen mass-loss data for polyethylene were not located in a readable source.",
    "Melting point of a virgin HDPE injection grade was not found in a readable source; the 128 °C value is from a pipe-grade table with flattened columns.",
    "Corrosion and ageing: no UV dose, exposure time or retained-property number for polyethylene was read in a fetched page. Search results gave carbonyl-index trends for UV-exposed PE films, but the pages that held them returned 403 or were not opened, so no figure is entered.",
    "Recipe: the atomic weights are NIST standard-atomic-weight intervals read on the NIST pages. The C and H shares are computed from C2H4, not printed in a source.",
    "Supply: no producer share, country split or polyethylene feedstock figure (ethylene from naphtha or ethane) was read in a fetched page in this pass."
  ],
  "story": {
    "why": "Polyethylene is an ethylene polymer used in two very different ways. In a lithium-ion cell, a thin microporous polyethylene separator shuts down near 130 °C by closing its pores, which the patent describes as its purpose. In engineering, polyethylene is an injection-molded plastic: a general-purpose HDPE grade H5818J has a density of 0.959 g/cm3 and a tensile strength at yield of 290 kg/cm2, and a PE-UHMW grade (Braskem Utec 3041) has a density of 925 kg/m3, a yield strength of 17 MPa and an elongation at break of 400 %.",
    "uses": [
      {
        "where": "Battery separator",
        "line": "A polyethylene microporous separator sits between the electrodes of a lithium-ion cell. A PP/PE/PP tri-layer uses the PE layer as the shutdown layer, which melts at 135 °C per an industry article."
      },
      {
        "where": "Injection-molded parts",
        "line": "H5818J is a general-purpose HDPE resin for injection molding. The recycled Recythen grade is listed at 950 kg/m3."
      }
    ],
    "can_do": [
      {
        "label": "Density",
        "line": "The virgin HDPE grade H5818J has a density of 0.959 g/cm3 (ASTM D 1505). The PE-UHMW grade Utec 3041 gives 925 kg/m3 (ASTM D 792).",
        "benchmark": "density",
        "scope": "material",
        "value": "0.959 g/cm3"
      },
      {
        "label": "Yield strength",
        "line": "The Braskem Utec 3041 page gives a tensile strength at yield of 17 MPa (ISO 527), with an elongation at break of 400 %.",
        "benchmark": "yield_strength",
        "scope": "material",
        "value": "17 MPa"
      },
      {
        "label": "Shutdown",
        "line": "A polyethylene microporous separator is described as shutting down at about 130 °C, with the shutdown to occur below 130 °C in the detailed description.",
        "benchmark": "melting_point",
        "scope": "material",
        "value": "130 °C"
      }
    ],
    "compare": "Within this profile, the UHMW-PE grade is 925 kg/m3 and the virgin HDPE grade is 0.959 g/cm3, so the UHMW grade is the lighter of the two. The stiffness is not comparable across the two sources: H5818J gives a flexural modulus of 13000 kg/cm2, and the Recythen grade a tensile modulus of 800 MPa.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Yield strength",
        "benchmark": "yield_strength",
        "scope": "material"
      }
    ],
    "handling": [
      "Dry the resin before molding: 80 °C for 2 to 3 h, with humidity at 0.15 % or less (Recythen).",
      "Note the grade. The H5818J values are one grade, and the UHMW-PE values are typical values for an unnamed grade."
    ],
    "good_for": [
      "Light plastic parts: 0.959 g/cm3 for the virgin HDPE injection grade, and 925 kg/m3 for the PE-UHMW grade.",
      "Tough, stretchy parts: the PE-UHMW grade elongates by 400 % before breaking.",
      "Battery separator shutdown: a polyethylene layer closes the pores near 130 °C."
    ],
    "watch_out": [
      "Heat: a polyethylene separator layer melts near 130 to 135 °C, and the Utec 3041 page gives no service temperature.",
      "Stiffness: the flexural modulus of H5818J is 13000 kg/cm2, and no modulus was taken for the PE-UHMW grade.",
      "Data gaps: no erosion yield in orbit, or outgassing value was found for this profile."
    ],
    "verdict": "Polyethylene is a light, tough plastic in its HDPE and UHMW forms, and the shutdown layer of many lithium-ion separators at about 130 °C. The sourced values are one virgin HDPE grade, a recycled HDPE, one PE-UHMW grade, and two separator statements. The orbital erosion and outgassing values are not in this profile.",
    "recipe": {
      "line": "Polyethylene repeat unit -CH2-CH2-, formula (C2H4)n (Wikipedia, Polyethylene). HDPE is defined as density 0.941 g/cm3 or more and is made with chromium/silica (Phillips), Ziegler-Natta or metallocene catalysts. LDPE is 0.910 to 0.940 g/cm3 and is made by free-radical polymerisation. UHMWPE has a molar mass of about 2 to 6 million daltons (Wikipedia, UHMWPE), made by coordination polymerisation with very active catalysts at high ethylene pressure.",
      "parts": [
        {
          "name": "Ethylene",
          "symbol": "C2H4",
          "role": "Only monomer for all three grades; grade differences come from catalyst, pressure and molar mass.",
          "share_note": "Single monomer, polymerised to the -CH2-CH2- repeat unit; atoms C2H4"
        },
        {
          "name": "Carbon",
          "symbol": "C",
          "role": "Standard atomic weight interval, NIST. Share computed from C2H4 (28.05 g/mol) with the NIST carbon value.",
          "atoms": 2,
          "share_percent": 85.6,
          "share_note": "atomic_weight [12.0096, 12.0116]"
        },
        {
          "name": "Hydrogen",
          "symbol": "H",
          "role": "Standard atomic weight interval, NIST. Share computed from C2H4.",
          "atoms": 4,
          "share_percent": 14.4,
          "share_note": "atomic_weight [1.00784, 1.00811]"
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The sources read here do not describe health effects of polyethylene. The one SDS page read (ChemicalBook, CAS 9002-88-4) prints no signal word and no hazard statements.",
        "points": [
          {
            "label": "Handling",
            "line": "The Recythen data sheet asks for pre-drying at 80 °C for 2 to 3 h before molding, and a processing humidity of 0.15 % or less."
          }
        ],
        "level": 1,
        "verdict": "No hazard statements printed"
      },
      {
        "title": "If it fails",
        "lead": "The failure route in the sources is thermal, inside a battery.",
        "points": [
          {
            "label": "Separator shutdown",
            "line": "A patent describes shutdown of a polyethylene separator around 130 °C, and an article gives the PE layer a melting point of 135 °C."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Service limits",
            "line": "The PE-UHMW grade Utec 3041 is listed with a yield strength of 17 MPa and an elongation at break of 400 %, both by ISO 527."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-18",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 13,
    "unreachable": 5,
    "caveats": 6,
    "note": "Values were read by an AI assistant on 2026-10-18 from the web pages named in each entry. Unreachable as readable text: the NASA LDEF erosion paper, the NIST polyethylene SDS, the Celanese GUR and TIVAR datasheets, and the Ensinger and IGEPA PE-UHMW PDFs. Caveats: the PE-UHMW values are for one grade (Utec 3041) read from a Material Data Center copy of the Braskem sheet; the H5818J values are a single grade; the HDPE pipe melting value comes from a table with flattened columns; the separator shutdown and melting values come from a patent and an article, not a measurement; the Recythen tensile value does not say whether it is yield or break; the CAS and hazard data come from a reseller-hosted SDS page."
  },
  "sources": {
    "scg-h5818j": {
      "title": "SCG Chemicals product grade page, H5818J general purpose HDPE for injection molding",
      "url": "https://www.scgchemicals.com/en/products-grade/h5818j",
      "kind": "datasheet",
      "license": "Manufacturer product page (cited, not reproduced)"
    },
    "recythen-hdpe": {
      "title": "Recythen HDPE, Interseroh Dienstleistungs GmbH, material data center entry",
      "url": "https://materialdatacenter.com/ms/en/Recythen/Interseroh+Dienstleistungs+GmbH/recythen®+HDPE/b74b37cd/6918",
      "kind": "datasheet",
      "license": "Supplier data sheet (cited, not reproduced)"
    },
    "pertachem-hdpe": {
      "title": "Pertachem, HDPE product table",
      "url": "https://pertachem.com/hdpe-en",
      "kind": "datasheet",
      "license": "Supplier web page (cited, not reproduced)"
    },
    "utec-3041": {
      "title": "Braskem Utec 3041 PE-UHMW data sheet, Material Data Center entry",
      "url": "https://materialdatacenter.com/ms/en/Utec/Braskem/Utec®+3041/7517bb03/487",
      "kind": "datasheet",
      "license": "Manufacturer data sheet (cited, not reproduced)"
    },
    "chemicalbook-pe-sds": {
      "title": "ChemicalBook, polyethylene MSDS (CAS 9002-88-4)",
      "url": "https://www.chemicalbook.com/msds/polyethylene.htm",
      "kind": "datasheet",
      "license": "Web SDS page (cited, not reproduced)"
    },
    "patent-us6749961": {
      "title": "US 6,749,961 B1, Shutdown battery separator made with a blend of polymer and oligomer",
      "url": "https://patents.google.com/patent/US6749961",
      "kind": "web",
      "license": "Patent text (public record)"
    },
    "volta-separators": {
      "title": "Lithium-ion Battery Separators and their Role in Safety, Volta Foundation",
      "url": "https://volta.foundation/lithium-ion-battery-separators-and-their-role-in-safety/",
      "kind": "web",
      "license": "Web article (cited, not reproduced)"
    },
    "nist-atomic-weights": {
      "title": "NIST Atomic Weights and Isotopic Compositions (standard atomic weight intervals for C, H, N, O)",
      "url": "https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=C&ascii=html",
      "year": 2026,
      "kind": "database",
      "license": "public domain (NIST)"
    },
    "wiki-polyethylene": {
      "title": "Wikipedia, Polyethylene (repeat unit, HDPE/LDPE density and routes, ageing and chemical resistance)",
      "url": "https://en.wikipedia.org/wiki/Polyethylene",
      "kind": "web",
      "license": "CC BY-SA (Wikipedia)"
    },
    "wiki-uhmwpe": {
      "title": "Wikipedia, Ultra-high-molecular-weight polyethylene (molar mass, route, UV, oxidation, chemicals)",
      "url": "https://en.wikipedia.org/wiki/Ultra-high-molecular-weight_polyethylene",
      "kind": "web",
      "license": "CC BY-SA (Wikipedia)"
    },
    "wiki-esc": {
      "title": "Wikipedia, Environmental stress cracking (polyethylene section and named tests)",
      "url": "https://en.wikipedia.org/wiki/Environmental_stress_cracking",
      "kind": "web",
      "license": "CC BY-SA (Wikipedia)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/polyethylene/"
}