Rheology of EPR/PP blends

The rheological behavior of polypropylene, PP, ethylene-propylene copolymer , EPR, and EPR/PP blends was studied. Zero-shear viscosity and elastic rela xation time were determined by least-squares fits by using a Carreau-Yasuda model with Arrhenius temperature dependency. The effect of PP and EPR mole cular weight, ethylene ratio in EPR copolymer (E/EPR), and EPR concentratio n on the zero-shear viscosity and elasticity of EPR/PP blends was determine d experimentally. Molecular weight effects are compared to theoretically ex pected relationships. EPR concentration effect and E/EPR ratio effects agre e well with predictions made by using the Tsenoglou model. (C) 2001 John Wi ley & Sons, Inc.