Comparative study of the effects of different fibers on the processing and properties of ternary composites based on PP-EPDM blends

The effects of the incorporation of different kinds of fibers on the physical and mechanical properties of thermoplastics elastomers based on blends of isotactic polypropylene (iPP) and ethylene-propylene diene rubber (EPDM) are described. For this purpose, three different compositions of PP-EPDM blends reinforced with fibers are studied and reported here. In particular, the flow behavior, mechanical properties (tensile, flexural and impact resistance) and morphology are examined. Rheological measurements confirm the viscosity increase of thermoplastics elastomers with the incorporation of the fibers. This increment is more evident in the presence of aramid fibers. In addition, the results obtained by dynamic-mechanical analysis and mechanical properties show that the fibers act. as an effective reinforcing agent of PP-EPDM blends. In fact, a significant increase of the modulus and strength is obtained in presence of all fibers, this effect being more noticeable at higher elastomer percentages in the thermoplastic. The morphology of the ternary composites is also analyzed by scanning electron microscopy (SEM). A good interfacial adhesion between fibers and matrix is observed, but also in this case, aramid fibers are the most effective ones.