Abstract: The deformation of polymers in processing contains shear and extensional components. It is identified that the dispersive mixing is strongly depended on shear stress or extensional stress and distributive mixing is mainly depended on the number of interfaces. Multiple-phase polymers can achieve a better mixing through extensional stress based on extensional disagglomeration. In this paper, a new mixing element prototype for single-screw extruder was developed and its dispersive and distributive mixing capacities and probability functions for stress and deformation rate in single screw processing was analyzed by Polyflow. The flowing trajectories obtained suggested that more and more particles were subjected to greater shear and extensional rates with increasing of time. Meanwhile, a long resistance time, no vortex flow and no stagnation of material in the processing showed a good shear and extensional mixing capacities of the new mixing element. Moreover, it was clear that the extensional mixing property was superior to that of shear mixing at low deformation rates from probability functions.

Key words: dispersion mixing, extensional flow, extensional disagglomeration, simulations