Abstract
An overview is given of extrudate distortions, flow fields and flow curves observed for flexible polymer melts, when they are extruded using axisymmetric or two-dimensional dies.
Die walls with high surface energy and low-energy slippery surfaces are considered, as well as the influence of wall roughness.
The connection between flow curves and the flow field structure is explained. Details of the extrudate distortions are given, focusing on the physical phenomena common to all polymer chemical species. A description of the second oscillating flow regime is included.
Recent results on ideal and on slippery surfaces are reviewed. An application of slippery surface extrusion to several commercial polyethylenes is presented. It is shown that cracks and flow oscillation distortions can be completely eliminated, and very significant quality and productivity improvements can be obtained using slippery surfaces.
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Piau, JM., El Kissi, N., Toussaint, F. et al. Distortions of polymer melt extrudates and their elimination using slippery surfaces. Rheol Acta 34, 40–57 (1995). https://doi.org/10.1007/BF00396053
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DOI: https://doi.org/10.1007/BF00396053