Materials / Compare
Plastic Polypropylene vs. Rubber
Compare Plastic Polypropylene 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 | 33MPasourcetypical, tensile stress at yield ISO 527 | not given (tensile used) |
| Ultimate tensile strength | not sourced | 23MPasourcetypical |
| Elongation at break | not sourced | 830%sourcetypical |
| Young's modulus (stiffness) | 1.45GPasourcetypical, tensile modulus ISO 527 | not sourced |
| Density | 900kg/m³sourcetypical, 23 °C ISO 1183-1 | 960kg/m³sourcetypical (specific gravity) |
| Strength to weight | 36.7kN·m/kg1.53x higher | 24kN·m/kg |
| Stiffness to weight | 1.61MN·m/kg | not sourced |
| Poisson's ratio | 0.42sourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) | 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 | 0.511GPa | not sourced |
| Bulk modulus | 3.02GPa | not sourced |
| Speed of sound | 1,269m/s | not sourced |
| Thermal | ||
| Thermal conductivity | 0.17–0.22W/m·Ksourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) | 0.151W/m·Ksourcegovernment selected value (US Army Natick Laboratories TR 66-49-PR, 1966), soft vulcanized natural rubber, 25 °C |
| Thermal expansion | 80–100µm/m·Ksourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) | not sourced |
| 100 mm part over a 50 °C swing | 450µm growth | not sourced |
| Specific heat | not sourced | 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) | not sourced | 0.0836mm²/s |
| Thermal shock resistance | 28.6W/m | not sourced |
| Max service temperature | 90°CsourceHDT 0.45 MPa (ISO 75B), unannealed | 70°Csourcecontinuous use operating range |
| Values for | LyondellBasell Moplen HP501H polypropylene homopolymer (general purpose), typical ISO values | 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 Polypropylene stronger than Rubber?
Plastic Polypropylene is stronger: its yield strength is 33 MPa against tensile strength 23 MPa for Rubber (43%).
Which is lighter, Plastic Polypropylene or Rubber?
Plastic Polypropylene is lighter: 900 kg/m³ against 960 kg/m³ for Rubber.
Which is lighter for the same job, Plastic Polypropylene or Rubber?
For the same stiffness or strength: Plastic Polypropylene is lighter for a strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Plastic Polypropylene | Rubber |
|---|---|---|
| Strong rod or tie | lighter | 1.53x heavier |
| Strong beam | lighter | 36% heavier |
| Strong panel or plate | lighter | 28% 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 Polypropylene or Rubber?
Plastic Polypropylene conducts heat better: 0.195 W/m·K against 0.151 W/m·K for Rubber.