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The tubing extrusion-forming process of a fluoropolymer (FEP) melt was studied both experimentally and numerically. The flow behaviour of a FEP resin was determined by using a tubular die used in industrial-scale operations and these data were compared with simulation results using (i) a viscous model (Cross) and (ii) a viscoelastic one (the Kaye – Bernstein, Kearsley, Zapas / Papanastasiou, Scriven, Macosko or K-BKZ/PSM model) in order to assess the viscoelastic effects. In all simulations, compressibility, thermal and pressure effects on viscosity were taken into account. It was found that the viscoelastic results for the pressure, and hence the stresses at the wall, were always higher than the viscous results. Both were higher than the experimental results. A quadratic slip model plus viscoelasticity was found necessary to reproduce the experiments. The smooth flow curves resulting from this industrial tubular-coating die are a further manifestation that this is an appropriate design for coating fluoropolymers at very high apparent shear rates, exceeding 5 000 s–1.
From E. Mitsoulis 1 | S. G. Hatzikiriakos 2
1School of Mining Engineering and Metallurgy, National Technical University of Athens, Athens, Greece
2Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, Canada
2Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, Canada
(Received 23.06.2011; accepted 01.09.2011)
Appeared in International Polymer Processing 2012/02, Page 259-269
DOI: 10.3139/217.2534
Direct link: http://www.polymer-process.com/IPP2534
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Tubing Extrusion of a Fluoropolymer Melt [1,15 MB]
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