In an effort toward developing better tribological properties of polycarbonate (PC), a reinforcement with calcium carbonate (CaCO3) nanoparticles (3% by weight), in the size range of 30-60nm, functionalized using stearic acid, was carried out by melt extrusion method. It was established that scratch resistance of PC/CaCO3 composites (PCC) improved by 30% in comparison with pure PC. Nevertheless, an assessment of thermal properties using thermogravimetric analysis and differential scanning calorimetry (DSC) indicated an inferior thermal stability of PCC. Thermomechanical properties as obtained from dynamic mechanical analysis revealed an improvement in storage modulus for PCC but loss tangent (tan ) results indicated lower glass transition (T-g) values in agreement with DSC results. To comprehend the thermal behavior of PCC, degradation kinetics was studied using the model-free method, and it was observed that the presence of organically modified nanoparticles resulted in catalysis of degradation, thus, lowering apparent activation energy (E) for PCC at the initial stages of degradation.