The rheology of thermoplastics under conditions of spiral flow and vibrations on extrusion

This paper describes the results of a theoretical and experimental study on the rheology of thermoplastics subjected to mechanical effects at extrusion conditions. The spiral flow of non-Newtonian systems has been studied and quantitative relationships obtained for its description, which are suitable for engineering. The effect of rotational low-frequency large-amplitude vibrations on the flow of melts in the extruder's head of simple (circular) and complex cross sections has been studied and an analysis provided for flow with small-amplitude high-frequency (ultrasonic) superimposed vibrations. The energy efficiency of cyclic deformation upon extrusion has been estimated. The investigation has provided recommendations for the application of complex shear as a method of directed action on the relaxation and, hence, rheological characteristics of polymers. This opens up new possibilities for the intensification of the extrusion processes and compositions based on thermoplastics.