Polycarbonate Repeating chemical structure unit of Polycarbonate made from bisphenol A]] Physical Properties Density (ρ)1.20–1.22 g/cm Abbe number (V)34.0 Refractive index (n)1.584–1.586 FlammabilityV0-V2 Limiting oxygen index25–27% Water absorption – Equilibrium(ASTM)0.16–0.35% Water absorption – over 24 hours0.1% Radiation resistanceFair Ultraviolet (1-380nm) resistanceFair Mechanical Properties Young’s modulus (E)2.0–2.4 GPa Tensile strength (σt)55–75 MPa Compressive strength (σc)>80 MPa Elongation (ε) @ break80–150% Poisson’s ratio (ν)0.37 Hardness – RockwellM70 Izod impact strength600–850 J/m Notch test20–35 kJ/m Abrasive resistance – ASTM D104410–15 mg/1000 cycles Coefficient of friction (μ)0.31 Speed of sound2270 m/s Thermal Properties Melting temperature (Tm)155 °C Glass transition temperature(Tg)147 °C Heat deflection temperature – 10 kN (Vicat B)145 °C Heat deflection temperature – 0.45 MPa140 °C Heat deflection temperature – 1.8 MPa128–138 °C Upper working temperature115–130 °C Lower working temperature−40 °C Linear thermal expansion coefficient (α)65–70 × 10/K Specific heat capacity (c)1.2–1.3 kJ/ Thermal conductivity (k) @ 23 °C0.19–0.22 W/(m·K) Thermal diffusivity (a) @ 25 °C0.144 mm²/s Electrical Properties Dielectric constant (εr) @ 1 MHz2.9 Permittivity (ε) @ 1 MHz2.568 × 10 F/m Relative permeability (μr) @ 1 MHz0.866(2) Permeability (μ) @ 1 MHz1.089(2) μN/A Dielectric strength15–67 kV/mm Dissipation factor @ 1 MHz0.01 Surface resistivity10 Ω/sq Volume resistivity (ρ)10–10 Ω·m Near to Short-wave Infrared Transmittance Spectrum Chemical Resistance Acids – concentratedPoor Acids – diluteGood AlcoholsGood AlkalisGood-Poor Aromatic hydrocarbonsPoor Greases & OilsGood-fair Halogenated HydrocarbonsGood-poor HalogensPoor KetonesPoor Gas permeation @ 20 °C Nitrogen 10 – 25 cm·mm/ Oxygen 70 – 130 cm·mm/(m·day·Bar) Carbon dioxide 400 – 800 cm·mm/(m·day·Bar) Water vapour 1–2 gram·mm/(m·day) @ 85%–0% RH gradient Economic Properties Price2.6 – 2.8 €/kg Polycarbonates (PC), known by the trademarked names Lexan, Makrolon, Makroclear and others, are a particular group of thermoplastic polymers.