Blending of Natural Rubber/Recycled Ethylene-Propylene-Diene Monomer: Cure Behaviors and Mechanical Properties

In this article, blending of natural rubber with recycled ethylene-propylene-diene monomer (R-EPDM) was studied. The comparative studies of cure behaviors, mechanical properties and morphology of natural rubber/recycled ethylene-propylene-diene monomer (NR/R-EPDM) and natural rubber/ethylene-propylene-diene monomer blends (NR/EPDM) were carried out. Results indicated that the maximum torque (MH), minimum torque (ML), scorch time (ts2) and cure time (tc90) of NR/EPDM increased with increasing virgin EPDM in the weight ratio of the blend. Similar observation was also obtained for NR/R-EPDM blend except for the ML and ts2 which exhibited the opposite trend. SEM micrographs proved that the incorporation of R-EPDM up to 30phr in the blends exhibited high roughness surface and matrix tearing line. Meanwhile, the micrographs of NR/EPDM blends showed a reduction in crack path with increasing virgin EPDM content, which led to less resistance for crack propagation and therefore, resulted in low tensile strength.