Materials / Compare
Plastic Polypropylene vs. Silicon
Compare Plastic Polypropylene vs. Silicon strength, stiffness, weight and thermal properties.
| Try it on a partA sample part 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 | 130MPasourcemodulus of rupture (bending fracture stress); brittle, no yield point |
| Flexural strength | not sourced | 130MPasourcemodulus of rupture |
| Elongation at break | not sourced | not sourced |
| Young's modulus (stiffness) | 1.45GPasourcetypical, tensile modulus ISO 527 | 131GPasourcetypical (single quoted value of an anisotropic crystal) |
| Density | 900kg/m³sourcetypical, 23 °C ISO 1183-1 | 2,329kg/m³sourcetypical |
| Strength to weight | 36.7kN·m/kg | 55.8kN·m/kg1.52x higher |
| Stiffness to weight | 1.61MN·m/kg | 56.2MN·m/kg34.9x higher |
| Poisson's ratio | 0.42sourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) | 0.221sourcetypical |
| Shear modulus | 0.511GPa | 53.6GPa105x stiffer in shear |
| Bulk modulus | 3.02GPa | 78.3GPa |
| Speed of sound | 1,269m/s | 7,500m/s |
| Thermal | ||
| Thermal conductivity | 0.17–0.22W/m·Ksourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) | 163W/m·Ksourcetypical at 313 K (40 °C) |
| Thermal expansion | 80–100µm/m·Ksourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene) | 2.62µm/m·Ksourcetypical at 300 K |
| 100 mm part over a 50 °C swing | 450µm growth | 13.1µm growth34.4x less |
| Specific heat | not sourced | 732J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | not sourced | 95.6mm²/s |
| Thermal shock resistance | 28.6W/m | 48,095W/m1,682x more resistant |
| Melting point | not sourced | 1,412°Csourcetypical |
| Max service temperature | 90°CsourceHDT 0.45 MPa (ISO 75B), unannealed | 300°Csourceproducer's maximum application temperature (optical components) |
| Values for | LyondellBasell Moplen HP501H polypropylene homopolymer (general purpose), typical ISO values | Synthetic single-crystal silicon (cubic, diamond structure), Korth Kristalle (crystal grower) material data; Korth usually supplies Floating Zone (FZ) material, Czochralski (Cz) also offered. Silicon is elastically anisotropic; the producer quotes one modulus and the solver is isotropic. |
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 Silicon?
Silicon is stronger: its tensile strength is 130 MPa against yield strength 33 MPa for Plastic Polypropylene (3.94x).
Which is lighter, Plastic Polypropylene or Silicon?
Plastic Polypropylene is lighter: 900 kg/m³ against 2,329 kg/m³ for Silicon.
Which is stiffer, Plastic Polypropylene or Silicon?
Silicon is stiffer: Young's modulus 131 GPa against 1.45 GPa for Plastic Polypropylene, so the same part in Silicon deflects less under the same load.
Which is lighter for the same job, Plastic Polypropylene or Silicon?
For the same stiffness or strength: Plastic Polypropylene is lighter for a strong beam, strong panel or plate; Silicon is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie.
| Part that must be | Plastic Polypropylene | Silicon |
|---|---|---|
| Stiff rod or tie (tension) | 34.9x heavier | lighter |
| Stiff beam (bending) | 3.67x heavier | lighter |
| Stiff panel or plate | 1.73x heavier | lighter |
| Strong rod or tie | 1.52x heavier | lighter |
| Strong beam | lighter | 4% heavier |
| Strong panel or plate | lighter | 30% 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 Silicon?
Silicon conducts heat better: 163 W/m·K against 0.195 W/m·K for Plastic Polypropylene.
Which expands less with temperature?
Silicon expands less: 2.62 µm/m·K against 90 µm/m·K for Plastic Polypropylene.