Materials / Compare
Plastic PEEK vs. Rubber
Compare Plastic PEEK vs. Rubber strength, stiffness, weight and thermal properties.
| Try it on a partA bracket to run stress or thermal on, free in your browser | Open in LessCAD | Open in LessCAD |
|---|---|---|
| Mechanical | ||
| Yield strength | 98MPasourcetypical, tensile yield | not given (tensile used) |
| Ultimate tensile strength | not sourced | 23MPasourcetypical |
| Compressive strength | 125MPasourcetypical, 23 C | not sourced |
| Flexural strength | 165MPasourcetypical, flexural stress at yield, 23 C | not sourced |
| Elongation at break | 25%sourcetypical, at break | 830%sourcetypical |
| Young's modulus (stiffness) | 4GPasourcetypical (nominal) | not sourced |
| Density | 1,300kg/m³sourcetypical (crystalline) | 960kg/m³sourcetypical (specific gravity) |
| Strength to weight | 75.4kN·m/kg3.15x higher | 24kN·m/kg |
| Stiffness to weight | 3.08MN·m/kg | not sourced |
| Poisson's ratio | 0.38sourcetypical | 0.5sourcegovernment (NBS J. Res. 68A, 1964): computed by NBS for peroxide-cured gum NR vulcanizate, 25 °C, infinitesimal deformation0.49 in the solver: the linear element locks as the ratio nears 0.5 (nearly incompressible). |
| Shear modulus | 1.45GPa | not sourced |
| Bulk modulus | 5.56GPa | not sourced |
| Speed of sound | 1,754m/s | not sourced |
| Thermal | ||
| Thermal conductivity | 0.29W/m·Ksourcetypical, average, 23 C | 0.151W/m·Ksourcegovernment selected value (US Army Natick Laboratories TR 66-49-PR, 1966), soft vulcanized natural rubber, 25 °C |
| Thermal expansion | 55µm/m·Ksourceaverage of flow/cross-flow, below Tg (<143 C) | not sourced |
| 100 mm part over a 50 °C swing | 275µm growth | not sourced |
| Specific heat | 2,200J/kg·Ksourcetypical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012) | 1,881J/kg·Ksourcegovernment (NBS J. Res. 68A, Table 7; values observed for unvulcanized NR by Bekkedahl and Matheson), 25 °C |
| Heats up and cools (diffusivity) | 0.101mm²/s21% faster | 0.0836mm²/s |
| Thermal shock resistance | 80.1W/m | not sourced |
| Melting point | 343°Csourcetypical, DSC | not sourced |
| Glass transition | 143°Csourceonset (midpoint 150 C) | not sourced |
| Max service temperature | 240°CsourceUL 746B RTI, mechanical strength (continuous use index) | 70°Csourcecontinuous use operating range |
| Values for | Victrex PEEK 450G (unreinforced, injection moulded), Victrex TDS rev. March 2026; Poisson from Victrex fluid-management flyer (2020-07) | Weir Minerals Linatex Premium rubber (95 % natural rubber), typical physical properties, spec sheet WMD0118/202305 |
Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Is Plastic PEEK stronger than Rubber?
Plastic PEEK is stronger: its yield strength is 98 MPa against tensile strength 23 MPa for Rubber (4.26x).
Which is lighter, Plastic PEEK or Rubber?
Rubber is lighter: 960 kg/m³ against 1,300 kg/m³ for Plastic PEEK.
Which is lighter for the same job, Plastic PEEK or Rubber?
For the same stiffness or strength: Plastic PEEK is lighter for a strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Plastic PEEK | Rubber |
|---|---|---|
| Strong rod or tie | lighter | 3.15x heavier |
| Strong beam | lighter | 1.94x heavier |
| Strong panel or plate | lighter | 1.52x 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 conducts heat better, Plastic PEEK or Rubber?
Plastic PEEK conducts heat better: 0.29 W/m·K against 0.151 W/m·K for Rubber.