The EPDM and PP ratios were varied as shown in Table 3 to fabricate the TPV materials with Shore A hardness values of 60, 70, and 80. The compression set results according to the EPDM/PP ratio are also presented in Table 3. It was found that the compression set was proportional to the PP ratio. TPV 60 (35.35 %) with a low PP ratio exhibits a compression set value (35.35%) which is 22.2% lower than that of TPV 80 (45.44 %) with a high PP ratio because PP has a yield strain of approximately 15% which undergoes permanent deformation under the 25% strain applied in the compression set test (Hartmann et al., 1987). The temperature-dependent tanδ curves are shown in Figure 5, where two peaks can be observed indicating the glass transition temperature (Tg) of EPDM (approximately -35 °C) and PP (approximately 10 °C), respectively (Xu et al., 2018). The tan δ peak values at the Tg of PP were similar among the samples, whereas the tanδ peak values at the Tg of EPDM increased significantly as the EPDM ratio increased. Near the EPDM Tg region, the tanδ value of TPV 60 was 0.478 which was 88.2% higher than that of TPV 80 (0.254). This result is reasonable because a larger energy is required for the molecular mobility of EPDM polymer chains with a high EPDM loading fraction in the TPV.