Materials / Compare
Plastic Polycarbonate vs. Rubber
Compare Plastic Polycarbonate 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 | 65MPasourcetypical, tensile yield | not given (tensile used) |
| Ultimate tensile strength | 65MPasourcetypical, stress at break | 23MPasourcetypical |
| Flexural strength | 97MPasourcetypical, flexural strength | not sourced |
| Elongation at break | 125%sourcetypical, strain at break | 830%sourcetypical |
| Young's modulus (stiffness) | 2.4GPasourcetypical | not sourced |
| Density | 1,200kg/m³sourcetypical | 960kg/m³sourcetypical (specific gravity) |
| Strength to weight | 54.2kN·m/kg2.26x higher | 24kN·m/kg |
| Stiffness to weight | 2MN·m/kg | not sourced |
| Poisson's ratio | 0.38sourcetypical, polycarbonate family (Covestro Part and Mold Design guide, Table 3-1) | 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 | 0.87GPa | not sourced |
| Bulk modulus | 3.33GPa | not sourced |
| Speed of sound | 1,414m/s | not sourced |
| Thermal | ||
| Thermal conductivity | 0.2W/m·Ksourcetypical, through-plane, 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 | 65µm/m·Ksourcetypical, 23-55 C, parallel and normal | not sourced |
| 100 mm part over a 50 °C swing | 325µm growth | not sourced |
| Specific heat | 1,172J/kg·Ksourcetypical (guide value), Bayer ASTM datasheet for Makrolon 2405, ASTM D 2766 | 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) | 0.142mm²/s1.7x faster | 0.0836mm²/s |
| Thermal shock resistance | 51.7W/m | not sourced |
| Glass transition | 144°Csourcetypical, DSC 10 C/min | not sourced |
| Max service temperature | 125°CsourceUL 746B RTI, tensile strength, 1.5 mm | 70°Csourcecontinuous use operating range |
| Values for | Covestro Makrolon 2405 general-purpose PC (MVR 19), Covestro technical datasheet version 2026-09-28, typical 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 Polycarbonate stronger than Rubber?
Plastic Polycarbonate is stronger: its yield strength is 65 MPa against tensile strength 23 MPa for Rubber (2.83x).
Which is lighter, Plastic Polycarbonate or Rubber?
Rubber is lighter: 960 kg/m³ against 1,200 kg/m³ for Plastic Polycarbonate.
Which is lighter for the same job, Plastic Polycarbonate or Rubber?
For the same stiffness or strength: Plastic Polycarbonate is lighter for a strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Plastic Polycarbonate | Rubber |
|---|---|---|
| Strong rod or tie | lighter | 2.26x heavier |
| Strong beam | lighter | 1.6x heavier |
| Strong panel or plate | lighter | 34% 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 Polycarbonate or Rubber?
Plastic Polycarbonate conducts heat better: 0.2 W/m·K against 0.151 W/m·K for Rubber.