Materials / Compare
Glass vs. Plastic UHMWPE
Compare Glass vs. Plastic UHMWPE 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 | not given (tensile used) | 20MPasourcetypical, tensile stress at yield ISO 527, 50 mm/min |
| Ultimate tensile strength | 41MPasourcetypical mean surface tensile stress at fracture (MOR), 60 s load, weathered, 50% breakage probability | 43MPasourcetypical, tensile stress at break ISO 527, 50 mm/min |
| Flexural strength | 41MPasourcemean MOR (same value as tensile) | not sourced |
| Elongation at break | not sourced | 465%sourcetypical, nominal elongation at break ISO 527 |
| Young's modulus (stiffness) | 72GPasourcetypical | 0.66GPasourcetypical, tensile modulus ISO 527, 1 mm/min |
| Density | 2,500kg/m³sourcetypical | 930kg/m³sourcetypical2.69x lighter |
| Strength to weight | 16.4kN·m/kg | 21.5kN·m/kg31% higher |
| Stiffness to weight | 28.8MN·m/kg40.6x higher | 0.71MN·m/kg |
| Poisson's ratio | 0.22sourcetypical | not sourced |
| Shear modulus | 29.5GPa | not sourced |
| Bulk modulus | 42.9GPa | not sourced |
| Speed of sound | 5,367m/s | 842m/s |
| Thermal | ||
| Thermal conductivity | 0.937W/m·Ksourcetypical at 75 F | 0.4W/m·Ksourcetypical, unfilled (narrative value, generic Celanese UHMWPE) |
| Thermal expansion | 8.3µm/m·Ksourcetypical, 75-575 F | 200µm/m·Ksourcetypical, 20 to 100 °C (generic Celanese UHMWPE) |
| 100 mm part over a 50 °C swing | 41.5µm growth24.1x less | 1,000µm growth |
| Specific heat | 880J/kg·Ksourcetypical at 75 F | not sourced |
| Heats up and cools (diffusivity) | 0.426mm²/s | not sourced |
| Thermal shock resistance | 50.1W/m | not sourced |
| Melting point | not sourced | 130–138°CsourceDSC 10 K/min |
| Max service temperature | 511°Csourcestrain point (ASTM C336) - stress-relaxation onset, not a rated service limit | 80°Csourcerecommended max constant operating temperature |
| Values for | Annealed soda-lime-silica float glass, Pilkington North America Technical Bulletin ATS-129 (04/2025) | Celanese GUR 4120 (avg. molecular weight 4.7x10^6 g/mol), typical values on compression-molded specimens; CTE and thermal conductivity from Celanese's generic UHMWPE guide (grade not named) |
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 Glass stronger than Plastic UHMWPE?
Glass is stronger: its tensile strength is 41 MPa against yield strength 20 MPa for Plastic UHMWPE (2.05x).
Which is lighter, Glass or Plastic UHMWPE?
Plastic UHMWPE is lighter: 930 kg/m³ against 2,500 kg/m³ for Glass.
Which is stiffer, Glass or Plastic UHMWPE?
Glass is stiffer: Young's modulus 72 GPa against 0.66 GPa for Plastic UHMWPE, so the same part in Glass deflects less under the same load.
Which is lighter for the same job, Glass or Plastic UHMWPE?
For the same stiffness or strength: Glass is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate; Plastic UHMWPE is lighter for a strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Glass | Plastic UHMWPE |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 40.6x heavier |
| Stiff beam (bending) | lighter | 3.89x heavier |
| Stiff panel or plate | lighter | 1.78x heavier |
| Strong rod or tie | 31% heavier | lighter |
| Strong beam | 1.67x heavier | lighter |
| Strong panel or plate | 1.88x 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, Glass or Plastic UHMWPE?
Glass conducts heat better: 0.937 W/m·K against 0.4 W/m·K for Plastic UHMWPE.
Which expands less with temperature?
Glass expands less: 8.3 µm/m·K against 200 µm/m·K for Plastic UHMWPE.