Materials / Compare
Plastic PBT GF30 vs. Plastic PEEK
Compare Plastic PBT GF30 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 | not given (tensile used) | 98MPasourcetypical, tensile yield |
| Ultimate tensile strength | 140MPasourcestress at break, 23 °C | not sourced |
| Compressive strength | not sourced | 125MPasourcetypical, 23 C |
| Flexural strength | 210MPasourcetypical, 23 °C | 165MPasourcetypical, flexural stress at yield, 23 C |
| Elongation at break | 3%sourcestrain at break, 23 °C | 25%sourcetypical, at break |
| Young's modulus (stiffness) | 9.8GPasourcetypical, 23 °C | 4GPasourcetypical (nominal) |
| Density | 1,530kg/m³sourcetypical | 1,300kg/m³sourcetypical (crystalline) |
| Strength to weight | 91.5kN·m/kg21% higher | 75.4kN·m/kg |
| Stiffness to weight | 6.41MN·m/kg2.08x higher | 3.08MN·m/kg |
| Poisson's ratio | not sourced | 0.38sourcetypical |
| Shear modulus | not sourced | 1.45GPa |
| Bulk modulus | not sourced | 5.56GPa |
| Speed of sound | 2,531m/s | 1,754m/s |
| Thermal | ||
| Thermal conductivity | 0.27W/m·Ksourcetypical (DIN 52612-1) | 0.29W/m·Ksourcetypical, average, 23 C |
| Thermal expansion | 25µm/m·Ksourcelongitudinal (flow), mean 23-55 °C | 55µm/m·Ksourceaverage of flow/cross-flow, below Tg (<143 C) |
| 100 mm part over a 50 °C swing | 125µm growth2.2x less | 275µm growth |
| Specific heat | 1,050J/kg·Ksourcetypical, 23 °C | 2,200J/kg·Ksourcetypical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012) |
| Heats up and cools (diffusivity) | 0.168mm²/s1.66x faster | 0.101mm²/s |
| Thermal shock resistance | not sourced | 80.1W/m |
| Melting point | 223°CsourceDSC (ISO 11357) | 343°Csourcetypical, DSC |
| Glass transition | not sourced | 143°Csourceonset (midpoint 150 C) |
| Max service temperature | 205°CsourceHDT 1.8 MPa | 240°CsourceUL 746B RTI, mechanical strength (continuous use index) |
| Values for | BASF Ultradur B 4300 G6 (PBT, 30% glass fibre), injection moulding grade; product information sheet 09/2026, typical values for uncoloured product at 23 °C. | 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 PBT GF30 stronger than Plastic PEEK?
Plastic PBT GF30 is stronger: its tensile strength is 140 MPa against yield strength 98 MPa for Plastic PEEK (43%).
Which is lighter, Plastic PBT GF30 or Plastic PEEK?
Plastic PEEK is lighter: 1,300 kg/m³ against 1,530 kg/m³ for Plastic PBT GF30.
Which is stiffer, Plastic PBT GF30 or Plastic PEEK?
Plastic PBT GF30 is stiffer: Young's modulus 9.8 GPa against 4 GPa for Plastic PEEK, so the same part in Plastic PBT GF30 deflects less under the same load.
Which is lighter for the same job, Plastic PBT GF30 or Plastic PEEK?
For the same stiffness or strength: Plastic PBT GF30 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 PBT GF30 | Plastic PEEK |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 2.08x heavier |
| Stiff beam (bending) | lighter | 33% heavier |
| Stiff panel or plate | lighter | 15% heavier |
| Strong rod or tie | lighter | 21% heavier |
| Strong beam | lighter | 8% heavier |
| Strong panel or plate | lighter | 2% 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 PBT GF30 or Plastic PEEK?
Plastic PEEK conducts heat better: 0.29 W/m·K against 0.27 W/m·K for Plastic PBT GF30.
Which expands less with temperature?
Plastic PBT GF30 expands less: 25 µm/m·K against 55 µm/m·K for Plastic PEEK.