The Cp variation of TiO2 filled NR at different concentrations including the reference sample with both temperature and filler concentrations are shown in Figure 2. The variation of Cp values with temperature follows the same pattern as Figure 1. The Cp values increase with TiO2 filler concentration remarkably up to 20 phr. Above 20 phr Cp values are almost same below temperature 75°C and begin to increase with filler concentrations above 75°C.