Rheological study of polypropylene copolymer/polyolefinic elastomer blends

Blends of polypropylene copolymer (PP-cp) and a polyolefinic elastomer (POE) were prepared by a melt-blending process at 210degreesC and 60 rpm using a counterrotating twin-screw extruder. The POE content was varied up to 25%. The shear viscosity over a wide range of shear rate was measured. All blend compositions showed well-defined zero shear viscosity and shear thinning behavior. The melt viscosity values were between those of the principal components in all cases. Rheology of blends shows different behavior up to concentrations of POE corresponding to the tough-brittle transition. The linear viscoelastic properties (G', G, eta*, eta', eta) were used to check the miscibility of the two components in the melt state. Ail blend compositions showed a good degree of miscibility over the range of POE concentrations studied. (C) 2002 John Wiley Sons, Inc.