Materials / Compare
Plastic HDPE vs. Plastic PMMA
Compare Plastic HDPE vs. Plastic PMMA 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 | 24MPasourcetypical, tensile stress at yield 23 °C, 50 mm/min ISO 527 | not given (tensile used) |
| Ultimate tensile strength | not sourced | 80MPasourcetypical, 23 °C |
| Compressive strength | not sourced | 110MPasourcecompressive yield stress, typical |
| Flexural strength | not sourced | 115MPasourcetypical |
| Elongation at break | not sourced | 5.5%sourcetypical |
| Young's modulus (stiffness) | 0.9GPasourcetypical, tensile modulus 23 °C ISO 527 | 3.3GPasourcetypical, short-term |
| Density | 950kg/m³sourcetypical, ISO 1183 | 1,190kg/m³sourcetypical |
| Strength to weight | 25.3kN·m/kg | 67.2kN·m/kg2.66x higher |
| Stiffness to weight | 0.947MN·m/kg | 2.77MN·m/kg2.93x higher |
| Poisson's ratio | 0.4–0.45sourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 0.37sourcetypical |
| Shear modulus | 0.316GPa | 1.2GPa3.81x stiffer in shear |
| Bulk modulus | 2GPa | 4.23GPa |
| Speed of sound | 973m/s | 1,665m/s |
| Thermal | ||
| Thermal conductivity | 0.4–0.49W/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 0.19W/m·Ksourcetypical |
| Thermal expansion | 120µm/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 70µm/m·Ksource0-50 °C |
| 100 mm part over a 50 °C swing | 600µm growth | 350µm growth1.71x less |
| Specific heat | 2,250J/kg·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 1,470J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | 0.208mm²/s1.92x faster | 0.109mm²/s |
| Thermal shock resistance | 56.9W/m37% more resistant | 41.5W/m |
| Max service temperature | not sourced | 80°Csourcemax. permanent service temperature |
| Values for | LyondellBasell Hostalen 23050 B high density polyethylene, typical ISO values | Röhm PLEXIGLAS GS 0F00 cast acrylic sheet, typical values at 23 °C / 50 % RH (Röhm Technical Information Ref. No. 211-1) |
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 HDPE stronger than Plastic PMMA?
Plastic PMMA is stronger: its tensile strength is 80 MPa against yield strength 24 MPa for Plastic HDPE (3.33x).
Which is lighter, Plastic HDPE or Plastic PMMA?
Plastic HDPE is lighter: 950 kg/m³ against 1,190 kg/m³ for Plastic PMMA.
Which is stiffer, Plastic HDPE or Plastic PMMA?
Plastic PMMA is stiffer: Young's modulus 3.3 GPa against 0.9 GPa for Plastic HDPE, so the same part in Plastic PMMA deflects less under the same load.
Which is lighter for the same job, Plastic HDPE or Plastic PMMA?
For the same stiffness or strength: Plastic PMMA 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 HDPE | Plastic PMMA |
|---|---|---|
| Stiff rod or tie (tension) | 2.93x heavier | lighter |
| Stiff beam (bending) | 1.53x heavier | lighter |
| Stiff panel or plate | 23% heavier | lighter |
| Strong rod or tie | 2.66x heavier | lighter |
| Strong beam | 1.78x heavier | lighter |
| Strong panel or plate | 46% heavier | lighter |
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 HDPE or Plastic PMMA?
Plastic HDPE conducts heat better: 0.445 W/m·K against 0.19 W/m·K for Plastic PMMA.
Which expands less with temperature?
Plastic PMMA expands less: 70 µm/m·K against 120 µm/m·K for Plastic HDPE.