Ethylene–propylene–diene monomer (E

Ethylene–propylene–diene monomer (EPDM) or ethylene propylene rubber (EPR) elastomer is most frequently used as PP impact modifiers. Polyolefin elastomer (POE) is an ethylene–octene copolymer developed using a metallocene catalyst by Dow Chemical Co. POE is characterized by a narrow molecular weight distribution and homogeneous comonomer distribution. Compared with EPDM or EPR, POE exhibits significant performances when blended with the PP matrix.21-23 POE offers a controlled level of chain branching along the polymer backbone. The narrow composition and molecular weight distribution result in improved rheological behaviors such as better shear thinning behaviors, melt elasticity, etc. These improve dispersion and faster mixing in rubber modified PP blends. This results in better stiffness and toughness balance than traditional EPDM or EPR.24, 25 Compared with those of polymer/filler binary composites, the rheological behaviors of PP ternary composites are more complex. On the other hand, the rheological behavior of the filled polymers is quite different from that of the corresponding unmodified polymers because of the presence of interparticle interaction. The strength and degree of these interactions depend on the filler concentration, particle size, etc. The surface treatment of the filler can also significantly affect the rheological behaviors of the filled polymer composites because particle–particle and particle–matrix interactions vary with modifications in chemical composition.15, 26 Therefore, the interfacial interaction of the ternary composites plays an important role in its rheological behaviors.