Effect of Feeding Strategy on the Mechanical Properties of PP/Recycled EPDM/PP-G-MA Blends

In this work, thermoplastic elastomers based on polypropylene (PP) and recycled ethylene-propylene-diene monomer (r-EPDM) blends with polypropylene-graft-maleic anhydride (PP-g-MA) as modifier (0 to 8 wt.%) were prepared by melt compounding via twin-screw extrusion followed by injection molding. In particular, the effects of material composition and feeding strategies were studied. The morphological and mechanical properties of the blends were investigated by using scanning electron microscopy (SEM), tensile, flexural, impact, density and hardness tests. The results indicate that good dispersion and compatibility between PP and r-EPDM particles was obtained and that incorporation of r-EPDM leads to significant increase in PP impact strength. Finally, the feeding order of each component in the extruder was found to modify substantially the final morphology of the blend, thus having a direct influence on their mechanical properties.