Draw Resonance Studies on Polypropylene Melts
Draw resonance is an instability phenomenon associated only with stretching motions. The instability was first observed by Christensen1 in the extrusion coating process of polypropylene. Since then it has been observed in processes such as fibre spinning and film extrusion for a wide variety of polymeric liquids. The instability manifests itself in the occurrence of periodic fluctuations in the extrudate dimensions (fibre diameter or film thickness) when a certain critical value of the take-up speed is exceeded. Diameter fluctuations of 5 to 30% are not uncommon in commercial practice. As the occurrence of draw resonance can considerably limit productivity or can deteriorate product uniformity, its study is of significant importance for polymer processing. In particular during the last decade several researchers have studied the phenomenon of draw resonance, both theoretically and experimentally.
KeywordsMass Flow Rate Molecular Weight Distribution Draw Ratio Newtonian Liquid Stanton Number
Unable to display preview. Download preview PDF.
- 1.R.E. Christensen, “Extrusion Coating of Polypropylene”, S.P. E. Journal, 18, 751 (1962).Google Scholar
- 15.L.L.Blyler and C. Gieniewski, “Melt Spinning and Draw Resonance Studies on a Poly (a-methylstyrene/silicone) Block Copolymer”, Pol. Eng. Sci. in press.Google Scholar
- 16.P. Lamb, “Analysis of Fabrication Processes”, SCI Monograph No. 26, 296 (1967).Google Scholar