Abstract In this study, the effect of paraffin (PR) and copper (Cu) incorporation in polycarbonate (PC) was investigated using differential scanning calorimetry (DSC). The effect of PR incorporation in PC was investigated using thermogravimetric analysis (TGA). The effect of thermal treatments on thermophysical properties was studied in PC/PR and PC/Cu composites by using the hot-disk method and a periodic method (DICO). Specimens were heated at 160°C (T g + 15°C), then two different cooling methods were employed: furnace cooling (annealing) and water cooling (quenching) at 0°C and 35°C. The DSC results showed that a solid-liquid transition occurred in all PR formulations, as well as showed the plasticizing role of the PR additive. Thermal stability decreased with the addition of PR. Thermal conductivities (λ) increased with increasing Cu content and decreased with PR additive content, and the annealed samples showed a higher thermal conductivity (λ) than quenched ones. Meanwhile, a small difference between the thermal conductivity of the DICO samples and the hot-disk samples was noticed.