The commercial application of polymer blends is undoubtedly the result of extensive research in this field. However, sometimes poor performance results from incompatibility of components in the blends, which in turn affects processibility. Processing is in large part simply flow and forming of compounds. A major problem often encountered in industry is batch-to-batch variation of viscosity and elastic memory of the compound, two characteristics which largely determine the compound's processability and dimensional stability. Efficient and quality production require reproducibility in the processing stages [1–4]. If a polymer melt is sheared mechanically, it can then be processed in a less elastic and less viscous state provided that the recovery of a more fully entangled, equilibrium state is not too fast [5]. Mechanical shear may reduce entanglement density r6–81. Shear modifications are manifested in changes in viscosities, die swell, die entrance pressure losses, melt fracture, etc. Various methods have also been developed over the years for rheological characterisation of polymer melts (9–17).