Analysis of morphology development of immiscible blends in a twin screw extruder

Abstract

Blending processes are primarily carried out in corotating intermeshing twin screw extruders. Because the knowledge about morphology development in such extruders is limited methods to obtain a desired morphology are based on empirical values and screening experiments. For the analysis of morphology evolution, a new special sampling device was developed which enables melt sampling in time periods of less than 10 seconds. With this technique integrated in an intermeshing corotating twin screw extruder, ZSK 40, it is possible to detect morphology development along the extruder screw nearly in real time. The performance of the developed method was verified by observation of morphology development in a polypropylene/polyamide-6 blend system along a screw section. A difference in morphology development caused by a variation of the screw rotational speed was observed. Furthermore, drop deformations in partially filled screw sections could be detected. © 1997 John Wiley & Sons, Inc.