Materials / Compare
Plastic PEEK vs. Plastic PTFE
Compare Plastic PEEK vs. Plastic PTFE 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 | 98MPasourcetypical, tensile yield | 9MPasourcetypical yield strength at 23 °C (Teflon PTFE, Table 8) |
| Ultimate tensile strength | not sourced | 39.3MPasourcetypical, skived tape 0.13 mm |
| Compressive strength | 125MPasourcetypical, 23 C | not sourced |
| Flexural strength | 165MPasourcetypical, flexural stress at yield, 23 C | not sourced |
| Elongation at break | 25%sourcetypical, at break | 350%sourcetypical, skived tape 0.13 mm |
| Young's modulus (stiffness) | 4GPasourcetypical (nominal) | not sourced |
| Density | 1,300kg/m³sourcetypical (crystalline) | 2,160kg/m³sourcetypical (standard specific gravity, ASTM D4894) |
| Strength to weight | 75.4kN·m/kg18.1x higher | 4.17kN·m/kg |
| Stiffness to weight | 3.08MN·m/kg | not sourced |
| Poisson's ratio | 0.38sourcetypical | 0.46sourcetypical, 23 °C (Teflon PTFE resins, Chemours handbook) |
| Shear modulus | 1.45GPa | not sourced |
| Bulk modulus | 5.56GPa | not sourced |
| Speed of sound | 1,754m/s | not sourced |
| Thermal | ||
| Thermal conductivity | 0.29W/m·Ksourcetypical, average, 23 C | 0.25W/m·Ksourcetypical, granular resin, 4.6 mm specimen |
| Thermal expansion | 55µm/m·Ksourceaverage of flow/cross-flow, below Tg (<143 C) | 100µm/m·Ksourcetypical, granular resin, 23-60 °C (ASTM E228) |
| 100 mm part over a 50 °C swing | 275µm growth1.82x less | 500µm growth |
| Specific heat | 2,200J/kg·Ksourcetypical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012) | 1,400J/kg·Ksourcetypical, granular resin, 20 °C (ASTM D4591) |
| Heats up and cools (diffusivity) | 0.101mm²/s23% faster | 0.0827mm²/s |
| Thermal shock resistance | 80.1W/m | not sourced |
| Melting point | 343°Csourcetypical, DSC | 327°Csourcesecond melting peak (sintered polymer), +/-10 |
| Glass transition | 143°Csourceonset (midpoint 150 C) | not sourced |
| Max service temperature | 240°CsourceUL 746B RTI, mechanical strength (continuous use index) | 260°Csourceservice temperature (Chemours general Teflon PTFE statement) |
| Values for | Victrex PEEK 450G (unreinforced, injection moulded), Victrex TDS rev. March 2026; Poisson from Victrex fluid-management flyer (2020-07) | Chemours Teflon PTFE 7C X granular molding resin, typical values (tensile/elongation measured on 0.13 mm skived tape) |
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 PEEK stronger than Plastic PTFE?
Plastic PEEK is stronger: its yield strength is 98 MPa against 9 MPa for Plastic PTFE (10.9x).
Which is lighter, Plastic PEEK or Plastic PTFE?
Plastic PEEK is lighter: 1,300 kg/m³ against 2,160 kg/m³ for Plastic PTFE.
Which is lighter for the same job, Plastic PEEK or Plastic PTFE?
For the same stiffness or strength: Plastic PEEK is lighter for a strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Plastic PEEK | Plastic PTFE |
|---|---|---|
| Strong rod or tie | lighter | 18.1x heavier |
| Strong beam | lighter | 8.16x heavier |
| Strong panel or plate | lighter | 5.48x 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 PEEK or Plastic PTFE?
Plastic PEEK conducts heat better: 0.29 W/m·K against 0.25 W/m·K for Plastic PTFE.
Which expands less with temperature?
Plastic PEEK expands less: 55 µm/m·K against 100 µm/m·K for Plastic PTFE.