Thermal conductivity against densityHigher and further left: spreads more heat for its weightThermal expansion against thermal conductivityLower and further right: warps less when heated
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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 Polycarbonate
Covestro Makrolon 2405 general-purpose PC (MVR 19), Covestro technical datasheet version 2026-09-28, typical values
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Makrolon 2405 Technical Data SheetCovestroPlastic Polycarbonate · Yield strength: typical, tensile yieldPlastic Polycarbonate · Ultimate tensile strength: typical, stress at breakPlastic Polycarbonate · Flexural strength: typical, flexural strengthPlastic Polycarbonate · Elongation at break: typical, strain at breakPlastic Polycarbonate · Young's modulus (stiffness): typicalPlastic Polycarbonate · Density: typicalPlastic Polycarbonate · Thermal conductivity: typical, through-plane, 23 CPlastic Polycarbonate · Thermal expansion: typical, 23-55 C, parallel and normalPlastic Polycarbonate · Glass transition: typical, DSC 10 C/minPlastic Polycarbonate · Max service temperature: UL 746B RTI, tensile strength, 1.5 mm
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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
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Engineering Polymers Part and Mold Design: Thermoplastics, A Design GuideCovestroarchived copyPlastic Polycarbonate · Poisson's ratio: typical, polycarbonate family (Covestro Part and Mold Design guide, Table 3-1)
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Makrolon 2405 Data Sheet, ASTM valuesBayer MaterialSciencearchived copyPlastic Polycarbonate · Specific heat: typical (guide value), Bayer ASTM datasheet for Makrolon 2405, ASTM D 2766
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 Polycarbonate?
Plastic PBT GF30 is stronger: its tensile strength is 140 MPa against yield strength 65 MPa for Plastic Polycarbonate (2.15x).
Which is lighter, Plastic PBT GF30 or Plastic Polycarbonate?
Plastic Polycarbonate is lighter: 1,200 kg/m³ against 1,530 kg/m³ for Plastic PBT GF30.
Which is stiffer, Plastic PBT GF30 or Plastic Polycarbonate?
Plastic PBT GF30 is stiffer: Young's modulus 9.8 GPa against 2.4 GPa for Plastic Polycarbonate, 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 Polycarbonate?
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 Polycarbonate
Stiff rod or tie (tension)
lighter
3.2x heavier
Stiff beam (bending)
lighter
1.58x heavier
Stiff panel or plate
lighter
25% heavier
Strong rod or tie
lighter
1.69x heavier
Strong beam
lighter
31% heavier
Strong panel or plate
lighter
15% 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 Polycarbonate?
Plastic Polycarbonate stretches further before it breaks: 125% elongation at break against 3% for Plastic PBT GF30.
Thermal
Which conducts heat better, Plastic PBT GF30 or Plastic Polycarbonate?
Plastic PBT GF30 conducts heat better: 0.27 W/m·K against 0.2 W/m·K for Plastic Polycarbonate.
Which expands less with temperature?
Plastic PBT GF30 expands less: 25 µm/m·K against 65 µm/m·K for Plastic Polycarbonate.