Studies of Thermal Conductivity of Nano CaCO3/HIPS Composites by Unsteady State Technique and Simulation with Nielsen's Model

Differential scanning calorimeter (DSC) and thermal conductivity meter were used for measurement of thermal conductivity by unsteady state technique of the high impact polystyrene (HIPS) composites filled with 0.5, 1.5, and 2.5 wt.% of CaCO₃ nano particles. A comparison of experimental and theoretical values of (K _c /K _m) was done using MATLAB software fitting in Nielsen's model of thermal conductivity for polymers containing low limit of volume fraction. The packing fraction (Φ _max) and geometry and orientation dependent parameter (A) of the nanofiller were assumed as 0.10 and 100, respectively, which are most fitted for this model. The effect of nanosize on thermal conductivity was well predicted by plotting different values of thermal conductivity at various source temperatures. The violation of the theoretical values because of local molecular vibration at higher temperature is highlighted promisingly in the plots.