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 to calculate the elastic interfacial contribution to the shear stress (σ12,int), and first normal stress difference (N1,int). The ratio N1,int/σ12,int can be linked to the orientation angle of the inclusions. Under steady state flow the Maffettone–Minale model gives an analytical expression between the orientation angle and the capillary number. In this manner the capillary number can be deduced from the orientation angle. From this the droplet size is calculated. Good agreement is found between the results and droplet sizes determined independently from dynamic measurements using 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.