300°Csourceproducer's maximum application temperature (optical components)
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.
Synthetic single-crystal silicon (cubic, diamond structure), Korth Kristalle (crystal grower) material data; Korth usually supplies Floating Zone (FZ) material, Czochralski (Cz) also offered. Silicon is elastically anisotropic; the producer quotes one modulus and the solver is isotropic.
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 Silicon?
Plastic PBT GF30 is stronger: its tensile strength is 140 MPa against 130 MPa for Silicon (8%).
Which is lighter, Plastic PBT GF30 or Silicon?
Plastic PBT GF30 is lighter: 1,530 kg/m³ against 2,329 kg/m³ for Silicon.
Which is stiffer, Plastic PBT GF30 or Silicon?
Silicon is stiffer: Young's modulus 131 GPa against 9.8 GPa for Plastic PBT GF30, so the same part in Silicon deflects less under the same load.
Which is lighter for the same job, Plastic PBT GF30 or Silicon?
For the same stiffness or strength: Plastic PBT GF30 is lighter for a strong rod or tie, strong beam, strong panel or plate; Silicon is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate.
Part that must be
Plastic PBT GF30
Silicon
Stiff rod or tie (tension)
8.78x heavier
lighter
Stiff beam (bending)
2.4x heavier
lighter
Stiff panel or plate
1.56x heavier
lighter
Strong rod or tie
lighter
1.64x heavier
Strong beam
lighter
1.6x heavier
Strong panel or plate
lighter
1.58x 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 Silicon?
Silicon conducts heat better: 163 W/m·K against 0.27 W/m·K for Plastic PBT GF30.
Which expands less with temperature?
Silicon expands less: 2.62 µm/m·K against 25 µm/m·K for Plastic PBT GF30.