Morphology development in shear flows of straight and folded molten fibers

The morphological evolution of straight and folded molten fibers in shear flows was systematically investigated. Shear flows represent local flow conditions within actual batch mixers and extruders. Folded fibers were of interest, since folding may occur during melt processing and since folded fibers resemble portions of more complex extended structures arising in polymer blends. A general, three‐dimensional numerical model of the time‐dependent fluid flows within the molten‐fiber phase and major‐phase fluid was developed. Interactions between both fluids via fully dynamical, three‐dimensional interfaces were considered. The relation of morphological changes in the fibers to the flow field for specified interfacial tensions and viscosity ratios are presented.