Rheological properties, tensile properties, and morphology of PP/EPDM/lonomer ternary blends

The rheological and tensile properties and the morphology of polypropylene (PP)/ethylenepropylene‐diene terpolymer(EPDM)/ionomer ternary blends were investigated, using a rheometric dynamic spectrometer (RDS), a dynamic mechanical thermal analyzer (DMTA), a tensile tester, and a scanning electron microscope (SEM). Two kinds of poly(ethylene‐ co ‐methacrylic acid) (EMA) ionomers, neutralized with different metal ions (Na + and Zn ++ ), were used. Blends were melt‐mixed, using a laboratory internal mixer at 190°C. The composition of PP and EPDM was fixed at 50/50 by wt % and the EMA ionomer contents were varied from 5 to 20 wt %, based on the total amount of PP and EPDM. It was found that the ternary blends, containing Na‐neutralized ionomer, showed considerably different rheological properties and morphology as compared to the PP/EPDM binary blends, due to the compatibilizing effect of the ionomer for PP and EPDM, while the ternary blends, containing the Zn‐neutralized ionomer, did not. The compatibilizing effect was most prominent at 5 wt % ionomer concentration.