Thermal conductivity against densityHigher and further left: spreads more heat for its weightThermal expansion against thermal conductivityLower and further right: warps less when heated
Try it on a partA bracket to run stress or thermal on, free in your browser
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.
Plastic PEEK
Victrex PEEK 450G (unreinforced, injection moulded), Victrex TDS rev. March 2026; Poisson from Victrex fluid-management flyer (2020-07)
1
VICTREX PEEK 450G Technical Data SheetVictrexPlastic PEEK · Yield strength: typical, tensile yieldPlastic PEEK · Compressive strength: typical, 23 CPlastic PEEK · Flexural strength: typical, flexural stress at yield, 23 CPlastic PEEK · Elongation at break: typical, at breakPlastic PEEK · Young's modulus (stiffness): typical (nominal)Plastic PEEK · Density: typical (crystalline)Plastic PEEK · Thermal conductivity: typical, average, 23 CPlastic PEEK · Thermal expansion: average of flow/cross-flow, below Tg (<143 C)Plastic PEEK · Melting point: typical, DSCPlastic PEEK · Glass transition: onset (midpoint 150 C)Plastic PEEK · Max service temperature: UL 746B RTI, mechanical strength (continuous use index)
2
Ultradur B 4300 G6 Product InformationBASFPlastic PBT GF30 · Ultimate tensile strength: stress at break, 23 °CPlastic PBT GF30 · Flexural strength: typical, 23 °CPlastic PBT GF30 · Elongation at break: strain at break, 23 °CPlastic PBT GF30 · Young's modulus (stiffness): typical, 23 °CPlastic PBT GF30 · Density: typicalPlastic PBT GF30 · Thermal conductivity: typical (DIN 52612-1)Plastic PBT GF30 · Thermal expansion: longitudinal (flow), mean 23-55 °CPlastic PBT GF30 · Specific heat: typical, 23 °CPlastic PBT GF30 · Melting point: DSC (ISO 11357)Plastic PBT GF30 · Max service temperature: HDT 1.8 MPa
3
VICTREX PEEK for Use in Fluid Management (2020)VictrexPlastic PEEK · Poisson's ratio: typical
4
VICTREX PEEK 450G Technical Data Sheet (2012)Victrexarchived copyPlastic PEEK · Specific heat: typical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012)
Each number points to the document that states it, with the exact basis. Values without a number are computed from the sourced ones. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Mechanical
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 is more ductile, Plastic PBT GF30 or Plastic PEEK?
Plastic PEEK stretches further before it breaks: 25% elongation at break against 3% for Plastic PBT GF30.
Thermal
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.