POLYMERS

Polycarbonate — Thermal Conductivity

Polycarbonate (PC) is a popular polymer material used among other things, for electric tool casings.

To optimize the production/molding process by finite element simulations, the thermophysical properties have to be known. The Thermal DiffusivityThermal diffusivity (a with the unit mm2/s) is a material-specific property for characterizing unsteady heat conduction. This value describes how quickly a material reacts to a change in temperature.thermal diffusivity can be determined not only in the solid region but also at temperatures above the Glass Transition TemperatureThe glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and food ingredients, etc., and describes the temperature region where the mechanical properties of the materials change from hard and brittle to more soft, deformable or rubbery.glass transition (> 140°C) if a molten material cell is employed in the LFA 457 MicroFlash®®. Together with the specific heat (measured with a DSC) and DensityThe mass density is defined as the ratio between mass and volume. density data, the Thermal ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.thermal conductivity can be determined. The slight increase in the thermal conductivity versus temperature is typical for 100% amorphous materials. Furthermore, the glass transition is visible in the specific heat curve and in the thermal diffusivity result. In the thermal conductivity result, this second order transition cannot be seen.