Role of Hydroxyl-Terminated Polybutadiene in Changing Properties of EPDM/ENR Blends

In this research, the effect of hydroxyl-terminated polybutadiene (HTPB) on processability, mechanical properties, thermal aging and oil resistance of 80/20 ethylene-propylene diene rubber/epoxidized natural rubber (EPDM/ENR) blend was investigated. The amount of HTPB used was varied from 0-4 parts per hundred of rubber (phr). The results revealed that addition of HTPB into EPDM/ENR blend decreased the compound viscosity, while scorch time and cure time slightly increased with increasing HTPB content. Furthermore, hardness, tensile and tear strengths of the blend decreased due to the poor dispersion of fillers in the presence of HTPB. After thermal aging treatment, the crosslink density of all EPDM/ENR blends increased leading to increasing in 100% modulus, tensile strength and swelling resistance, as well as reducing in elongation at break. However, it had additional plus features that high resilience with low compression set was achieved in the blend containing 2 phr of HTPB.