Thermal conductivity against densityHigher and further left: spreads more heat for its weightThermal expansion against thermal conductivityLower and further right: warps less when heated
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DuPont Delrin 100 acetal homopolymer, Table 2 'Typical Properties of Delrin Acetal Resins' (ASTM methods), Delrin Design Guide Module III hosted on delrin.com
Plastic UHMWPE
Celanese GUR 4120 (avg. molecular weight 4.7x10^6 g/mol), typical values on compression-molded specimens; CTE and thermal conductivity from Celanese's generic UHMWPE guide (grade not named)
GUR UHMW-PE Overview (GUR-015)CelanesePlastic UHMWPE · Yield strength: typical, tensile stress at yield ISO 527, 50 mm/minPlastic UHMWPE · Ultimate tensile strength: typical, tensile stress at break ISO 527, 50 mm/minPlastic UHMWPE · Elongation at break: typical, nominal elongation at break ISO 527Plastic UHMWPE · Young's modulus (stiffness): typical, tensile modulus ISO 527, 1 mm/minPlastic UHMWPE · Density: typicalPlastic UHMWPE · Melting point: DSC 10 K/minPlastic UHMWPE · Max service temperature: recommended max constant operating temperature
3
Delrin 100 Product Data SheetDuPontPlastic POM/Acetal · Density: typical (DuPont product information for Delrin 100 NC010; 'The data listed here fall within the normal range of product properties')
4
GUR UHMW-PE Polymer Guide (GUR-003)Celanesearchived copyPlastic UHMWPE · Thermal conductivity: typical, unfilled (narrative value, generic Celanese UHMWPE)Plastic UHMWPE · Thermal expansion: typical, 20 to 100 °C (generic Celanese UHMWPE)
Each number points to the document that states it, with the exact basis. Values without a number are computed from the sourced ones. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Mechanical
Is Plastic POM/Acetal stronger than Plastic UHMWPE?
Plastic POM/Acetal is stronger: its yield strength is 69 MPa against 20 MPa for Plastic UHMWPE (3.45x).
Which is lighter, Plastic POM/Acetal or Plastic UHMWPE?
Plastic UHMWPE is lighter: 930 kg/m³ against 1,420 kg/m³ for Plastic POM/Acetal.
Which is stiffer, Plastic POM/Acetal or Plastic UHMWPE?
Plastic POM/Acetal is stiffer: Young's modulus 2.8 GPa against 0.66 GPa for Plastic UHMWPE, so the same part in Plastic POM/Acetal deflects less under the same load.
Which is lighter for the same job, Plastic POM/Acetal or Plastic UHMWPE?
For the same stiffness or strength: Plastic POM/Acetal is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.
Part that must be
Plastic POM/Acetal
Plastic UHMWPE
Stiff rod or tie (tension)
lighter
2.78x heavier
Stiff beam (bending)
lighter
35% heavier
Stiff panel or plate
lighter
6% heavier
Strong rod or tie
lighter
2.26x heavier
Strong beam
lighter
50% heavier
Strong panel or plate
lighter
22% heavier
For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).
Which is more ductile, Plastic POM/Acetal or Plastic UHMWPE?
Plastic UHMWPE stretches further before it breaks: 465% elongation at break against 75% for Plastic POM/Acetal.
Thermal
Which conducts heat better, Plastic POM/Acetal or Plastic UHMWPE?
Plastic POM/Acetal conducts heat better: 0.4 W/m·K against 0.4 W/m·K for Plastic UHMWPE.
Which expands less with temperature?
Plastic POM/Acetal expands less: 122 µm/m·K against 200 µm/m·K for Plastic UHMWPE.