Materials / Compare
Plastic Nylon PA66 vs. Plastic PEEK
Compare Plastic Nylon PA66 vs. Plastic PEEK 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 | 85MPasourcetypical, dry | 98MPasourcetypical, tensile yield |
| Ultimate tensile strength | not sourced | not sourced |
| Compressive strength | not sourced | 125MPasourcetypical, 23 C |
| Flexural strength | not sourced | 165MPasourcetypical, flexural stress at yield, 23 C |
| Elongation at break | 30%sourcenominal strain at break, dry | 25%sourcetypical, at break |
| Young's modulus (stiffness) | 3GPasourcetypical, dry | 4GPasourcetypical (nominal) |
| Density | 1,130kg/m³sourcetypical | 1,300kg/m³sourcetypical (crystalline) |
| Strength to weight | 75.2kN·m/kg | 75.4kN·m/kg |
| Stiffness to weight | 2.65MN·m/kg | 3.08MN·m/kg16% higher |
| Poisson's ratio | 0.4sourcebase material: unfilled polyamide (PA), conditioned, maker design-guide family value (Covestro Table 3-1) | 0.38sourcetypical |
| Shear modulus | 1.07GPa | 1.45GPa35% stiffer in shear |
| Bulk modulus | 5GPa | 5.56GPa |
| Speed of sound | 1,629m/s | 1,754m/s |
| Thermal | ||
| Thermal conductivity | 0.33W/m·Ksourcetypical | 0.29W/m·Ksourcetypical, average, 23 C |
| Thermal expansion | 98µm/m·Ksourcelongitudinal, 23-55 °C | 55µm/m·Ksourceaverage of flow/cross-flow, below Tg (<143 C) |
| 100 mm part over a 50 °C swing | 490µm growth | 275µm growth1.78x less |
| Specific heat | 1,700J/kg·Ksourcetypical | 2,200J/kg·Ksourcetypical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012) |
| Heats up and cools (diffusivity) | 0.172mm²/s1.69x faster | 0.101mm²/s |
| Thermal shock resistance | 57.2W/m | 80.1W/m40% more resistant |
| Melting point | 260°CsourceDSC | 343°Csourcetypical, DSC |
| Glass transition | not sourced | 143°Csourceonset (midpoint 150 C) |
| Max service temperature | 101°CsourceIEC 60216 temperature index, 20000 h | 240°CsourceUL 746B RTI, mechanical strength (continuous use index) |
| Values for | BASF Ultramid A3K (PA66, unreinforced injection-moulding grade), Product Information 02/2026, dry values (ISO methods) | Victrex PEEK 450G (unreinforced, injection moulded), Victrex TDS rev. March 2026; Poisson from Victrex fluid-management flyer (2020-07) |
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 Nylon PA66 stronger than Plastic PEEK?
Plastic PEEK is stronger: its yield strength is 98 MPa against 85 MPa for Plastic Nylon PA66 (15%).
Which is lighter, Plastic Nylon PA66 or Plastic PEEK?
Plastic Nylon PA66 is lighter: 1,130 kg/m³ against 1,300 kg/m³ for Plastic PEEK.
Which is stiffer, Plastic Nylon PA66 or Plastic PEEK?
Plastic PEEK is stiffer: Young's modulus 4 GPa against 3 GPa for Plastic Nylon PA66, so the same part in Plastic PEEK deflects less under the same load.
Which is lighter for the same job, Plastic Nylon PA66 or Plastic PEEK?
For the same stiffness or strength: Plastic Nylon PA66 is lighter for a stiff panel or plate, strong beam, strong panel or plate; Plastic PEEK is lighter for a stiff rod or tie (tension).
| Part that must be | Plastic Nylon PA66 | Plastic PEEK |
|---|---|---|
| Stiff rod or tie (tension) | 16% heavier | lighter |
| Stiff beam (bending) | about equal | about equal |
| Stiff panel or plate | lighter | 5% heavier |
| Strong rod or tie | about equal | about equal |
| Strong beam | lighter | 5% heavier |
| Strong panel or plate | lighter | 7% 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 Nylon PA66 or Plastic PEEK?
Plastic Nylon PA66 conducts heat better: 0.33 W/m·K against 0.29 W/m·K for Plastic PEEK.
Which expands less with temperature?
Plastic PEEK expands less: 55 µm/m·K against 98 µm/m·K for Plastic Nylon PA66.