Rheology and rheological morphology determination in immiscible two-phase polymer model blends

The Maffettone-Minale analysis describes the shape of ellipsoidal droplets in immiscible two-phase polymer model blends during flow. It is used here t o calculate the elastic interfacial contribution to the shear stress (sigma (12,int)), and first normal stress difference (N-1,N-int). The ratio N-1,N- int/sigma(12,int) can be linked to the orientation angle of the inclusions. Under steady state flow the Maffettone-Minale model gives an analytical ex pression between the orientation angle and the capillary number. In this ma nner the capillary number can be deduced from the orientation angle. From t his the droplet size is calculated, Good agreement is found between the res ults and droplet sizes determined independently from dynamic measurements u sing the Palierne model. The stresses calculated from the model, with given values for the droplet size, compare quite well with the stresses measured on a model system for relatively small capillary numbers. (C) 2000 Elsevie r Science B.V. All rights reserved.