Materials / Compare
Plastic HDPE vs. Plastic Nylon PA66
Compare Plastic HDPE vs. Plastic Nylon PA66 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 | 85MPasourcetypical, dry |
| Ultimate tensile strength | not sourced | not sourced |
| Elongation at break | not sourced | 30%sourcenominal strain at break, dry |
| Young's modulus (stiffness) | 0.9GPasourcetypical, tensile modulus 23 °C ISO 527 | 3GPasourcetypical, dry |
| Density | 950kg/m³sourcetypical, ISO 1183 | 1,130kg/m³sourcetypical |
| Strength to weight | 25.3kN·m/kg | 75.2kN·m/kg2.98x higher |
| Stiffness to weight | 0.947MN·m/kg | 2.65MN·m/kg2.8x higher |
| Poisson's ratio | 0.4–0.45sourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 0.4sourcebase material: unfilled polyamide (PA), conditioned, maker design-guide family value (Covestro Table 3-1) |
| Shear modulus | 0.316GPa | 1.07GPa3.39x stiffer in shear |
| Bulk modulus | 2GPa | 5GPa |
| Speed of sound | 973m/s | 1,629m/s |
| Thermal | ||
| Thermal conductivity | 0.4–0.49W/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 0.33W/m·Ksourcetypical |
| Thermal expansion | 120µm/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 98µm/m·Ksourcelongitudinal, 23-55 °C |
| 100 mm part over a 50 °C swing | 600µm growth | 490µm growth22% less |
| Specific heat | 2,250J/kg·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 1,700J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | 0.208mm²/s21% faster | 0.172mm²/s |
| Thermal shock resistance | 56.9W/m | 57.2W/m |
| Melting point | not sourced | 260°CsourceDSC |
| Max service temperature | not sourced | 101°CsourceIEC 60216 temperature index, 20000 h |
| Values for | LyondellBasell Hostalen 23050 B high density polyethylene, typical ISO values | BASF Ultramid A3K (PA66, unreinforced injection-moulding grade), Product Information 02/2026, dry values (ISO methods) |
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 Nylon PA66?
Plastic Nylon PA66 is stronger: its yield strength is 85 MPa against 24 MPa for Plastic HDPE (3.54x).
Which is lighter, Plastic HDPE or Plastic Nylon PA66?
Plastic HDPE is lighter: 950 kg/m³ against 1,130 kg/m³ for Plastic Nylon PA66.
Which is stiffer, Plastic HDPE or Plastic Nylon PA66?
Plastic Nylon PA66 is stiffer: Young's modulus 3 GPa against 0.9 GPa for Plastic HDPE, so the same part in Plastic Nylon PA66 deflects less under the same load.
Which is lighter for the same job, Plastic HDPE or Plastic Nylon PA66?
For the same stiffness or strength: Plastic Nylon PA66 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 Nylon PA66 |
|---|---|---|
| Stiff rod or tie (tension) | 2.8x heavier | lighter |
| Stiff beam (bending) | 1.53x heavier | lighter |
| Stiff panel or plate | 26% heavier | lighter |
| Strong rod or tie | 2.98x heavier | lighter |
| Strong beam | 1.95x heavier | lighter |
| Strong panel or plate | 1.58x 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 Nylon PA66?
Plastic HDPE conducts heat better: 0.445 W/m·K against 0.33 W/m·K for Plastic Nylon PA66.
Which expands less with temperature?
Plastic Nylon PA66 expands less: 98 µm/m·K against 120 µm/m·K for Plastic HDPE.