Molecular motion in mixtures of polymer melts in a capillary flow

The evolution of the morphology of two incompatible polymer melts in a capillary flow was studied using analytical electron microscopy. The spatial distribution of polysulfone and the liquid-crystal (LC) polymer was evaluated by measuring the concentration of sulfur (which is contained exclusively in polysulfone) and oxygen (contained in a much larger proportion in the LC polymer). The distributions of both polymers in the cross-sections of the strands do not change regardless of the specified shear rate, which varies by a factor of 25. However, a thin boundary layer with a width of about 10 mu m formed by a low-viscosity LC polymer was detected. Nevertheless, there is a strong deformation and orientation of both polymers. This indicates that the movement of the mixture through the capillary occurs not due to sliding along the boundary layer but also due to shear in the entire volume of the material. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study analyzed the evolution of the morphology of two incompatible polymer melts in a capillary flow using analytical electron microscopy. The spatial distribution and orientation of the polymers were found to be minimally affected by the specified shear rate, with a thin boundary layer formed by the low-viscosity LC polymer being the only significant change observed.