Authors: Roman Čermák Martin Obadal Veronika Habrová Karel Stoklasa Vincent Verney Sophie Commereuc Frédéric Fraïsse
Publish Date: 2005/11/04
Volume: 45, Issue: 4, Pages: 366-373
Abstract
In this study attention is directed towards the abilities of elongational flow to induce the chain orientation and as a consequence to improve the properties of extruded profiles A noveldesigned extrusion die with semihyperbolic convergency of the channel by which a high percentage of elongational flow in the melt is generated was connected with a conventional singlescrew extruder Commercial grades of highdensity polyethylene and isotactic polypropylene were used as model commodity polymers Round extrudates prepared by this processing line were assessed as selfreinforced products Detailed structural observation carried out with the aid of scanning electron microscopy and wideangle Xray scattering evidenced that the structure of extruded rods is uniquely fibrous and highly oriented throughout the profile As a result the selfreinforced extrudates possess outstanding storage modulus in a wide range of temperatures and considerably higher melting point and fusion heat than rods produced by conventional extrusionThe authors kindly acknowledge the support provided by the Czech Science Foundation GAČR project 106/03/P144 and the Ministry of Education Youth and Sports of the Czech Republic FRVŠ project G1 CR 2921/2005 The authors are also grateful to Prof Jaroslav Vaculík for his help in scanning electron microscopy and Mr Joël Cellier for WAXS measurements One of the authors RČ thanks ESNCCF/Université Blaise Pascal ClermontFerrand France and Tomas Bata University in Zlín Czech Republic for their support during his stay
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