From the theoretical and experimental data on the breakup of droplets, several factors influence: flow type & its intensity, viscosity ratio, elasticity of polymer, composition, thermodynamic interactions, and time etc. For Newtonian systems both the viscosity ratio and the capillary number control on the deformability of drops. Drops are more efficiently broken in the elongational flow than in shear, especially when the viscosity ratio λ ≥ 3.
The drop deformation and breakup are likely to be more difficult in visco-elastic systems than in Newtonian ones. There is no theory that is able to describe the deformability of visco-elastic droplet suspended in a visco-elastic or even a Newtonian medium. The effect of droplets coalescence on the final morphology should be considered, even at low concentration of the dispersed phase, ϕd ≥ 0.005.
However, they are of little direct use for the quantitative prediction of the polymer blend morphology during compounding in atwin screw extruder. Their value is limited to serving as general guides to the process modeling.