Visualization of Flow Instabilities for High Density Polyethylene
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H. Kometani
Abstract
Two typical flow instabilities of “Shark Skin” and “Melt Fracture” for high density polyethylene were investigated in this report. Experimental measurements were carried out methodically in a wide flow region from the reservoir (entry region) to the die land with a specific slit die. Especially the flow pattern was visualized with a high speed camera and the frequency of the flow instability was analyzed. Corresponding to the visualization analysis, the pressure fluctuation in the slit die and the surface roughness at the die exit were measured simultaneously and these frequency characteristics were analyzed with a FFT (Fast Fourier Transform) analyzer. As for “Shark Skin” region, the irregularity of the surface roughness in the broad frequency band was recognized at the die exit. In spite of this surface roughness, the pressure fluctuation and the fluctuation of the flow pattern at the wall vicinity in the die land were not observed. These results indicate that “Shark Skin” occurs at the die exit. As for “Melt Fracture” region, the periodical oscillation of the flow pattern and the periodical pressure fluctuation which corresponded to the periodical distortion of the extrudate was recognized in the die land. However the periodical oscillation of the flow pattern and the periodical pressure fluctuation could not be recognized in the reservoir (entry region of the die land). These results indicate that “Melt Fracture” is initiated at the die entry and occurs in the die land. Consequently it is clarified that “Shark Skin” occurs at the die exit and the flow instability which lead to “Melt Fracture” is initiated at the die entry and occurs in the die land.
References
1 Ramamurthy, A. V.: J. Rheol.30, p.337(1986).10.1122/1.549852Suche in Google Scholar
2 Ghanta, V. G., Riise, B. L., Denn, M. M.: J. Rheol.43, p.435(1999).10.1122/1.550988Suche in Google Scholar
3 Kurtz, S. J.: In Adv. Rheol. (Proc. 9th Intl. congr. Rheol.), p.399(1984).Suche in Google Scholar
4 El Kissi, N., Piau, J. M., Toussaint, F.: J. Non-Newtonian Fluid Mech.68, p.271(1997).10.1016/S0377-0257(96)01507-8Suche in Google Scholar
5 Hatzikiriakos, S. G., Stewart, C. W., Dealy, J. M.: Int. Polym. Process.8, p.30(1993).10.3139/217.930030Suche in Google Scholar
6 Hatzikiriakos, S. G., Dealy, J. M.: Int. Polym. Process.8, p.36(1993).10.3139/217.930036Suche in Google Scholar
7 Piau, J. M., El Kissi, N., Toussaint, F., Mezghani, A.: Rheol. Acta34, p.40(1995)10.1007/BF00396053Suche in Google Scholar
8 Cogswell, F. N.: J. Non-Newtonian Fluid Mech.2, p.37(1977).10.1016/0377-0257(77)80031-1Suche in Google Scholar
9 Wang, S. Q., Drda, P. A., Inn, Y. W.: J. Rheol.40, p.875(1996).10.1122/1.550766Suche in Google Scholar
10 Barone, J. R.Plucktaveesak, N., Wang, S. Q.: J. Rheol.42, p.813(1998).10.1122/1.550902Suche in Google Scholar
11 Mackley, M. R., Rutgers, R. P. G., Gilbert, D. G.: J. Non-Newtonian Fluid Mech.76, p.281(1998).10.1016/S0377-0257(97)00122-5Suche in Google Scholar
12 Rutgers, R. P. G., Mackley, M. R.: J. Rheol.44, p.1319(2000).10.1122/1.1319176Suche in Google Scholar
13 Tordella, J. P.: J. Appl. Polym. Sci.7, p.215(1963).10.1002/app.1963.070070119Suche in Google Scholar
14 Schott, H., Kaghan, W. S.: Ind. Eng. Chem.51, p.844(1959).10.1021/ie50595a034Suche in Google Scholar
15 Bagley, E. B., Birks, A. M.: J. Appl. Phys.31, p.556(1960).10.1063/1.1735627Suche in Google Scholar
16 den Otter, J. L.: Plast. Polym.38, p.155(1970).Suche in Google Scholar
17 Ballenger, T. F., White, J. L.: J. Appl. Polym. Sci.15, p.1949(1971).10.1002/app.1971.070150813Suche in Google Scholar
18 White, J. L.: Appl. Polym. Symp.20, p.155(1973).Suche in Google Scholar
19 Oyanagi, Y.: Appl. Polym. Symp.20, p.123(1973).Suche in Google Scholar
20 Kim, S., Dealy, J. M.: Polym. Eng. Sci.42, p.482(2002).10.1002/pen.10965Suche in Google Scholar
© 2006, Hanser Publishers, Munich
Artikel in diesem Heft
- Contents
- Contents
- Editorial
- Dedication of the Special Issue of International Polymer Processing in Honor of Prof. James Lindsay White, Editor Emeritus and Founding Editor
- Invited Papers
- Melt Compounding of Polymeric Nanocomposites
- Experiments and Analysis of Effect of Calender Gaps on Melting of PVC Powders in an Intermeshing Counter-rotating Twin-screw Extruder
- Quantitative Analysis for Polymer Degradation in the Extrusion Process
- Visualization of Flow Instabilities for High Density Polyethylene
- Heat Transfer through Metal Walls of Finite Thickness
- Simulation and Experimental Verification of Crystallization and Birefringence in Melt Spinning of PET
- Structural Development and Properties of Melt Spun Poly(butylene succinate) and Poly(butylene terephthalate-co-succinate-co-adipate) Biodegradable Fibers
- External Calibration in PA12 Tube Extrusion
- Tubular Film Extrusion Stability of Metallocene Linear Low Density Polyethylene
- Multilayer Barrier Film of Biaxially Oriented PA6/EVOH by Double Bubble Tubular Film Process
- PPS News
- PPS News
- Seikei-Kakou Abstracts
- Seikei-Kakou Abstracts
Artikel in diesem Heft
- Contents
- Contents
- Editorial
- Dedication of the Special Issue of International Polymer Processing in Honor of Prof. James Lindsay White, Editor Emeritus and Founding Editor
- Invited Papers
- Melt Compounding of Polymeric Nanocomposites
- Experiments and Analysis of Effect of Calender Gaps on Melting of PVC Powders in an Intermeshing Counter-rotating Twin-screw Extruder
- Quantitative Analysis for Polymer Degradation in the Extrusion Process
- Visualization of Flow Instabilities for High Density Polyethylene
- Heat Transfer through Metal Walls of Finite Thickness
- Simulation and Experimental Verification of Crystallization and Birefringence in Melt Spinning of PET
- Structural Development and Properties of Melt Spun Poly(butylene succinate) and Poly(butylene terephthalate-co-succinate-co-adipate) Biodegradable Fibers
- External Calibration in PA12 Tube Extrusion
- Tubular Film Extrusion Stability of Metallocene Linear Low Density Polyethylene
- Multilayer Barrier Film of Biaxially Oriented PA6/EVOH by Double Bubble Tubular Film Process
- PPS News
- PPS News
- Seikei-Kakou Abstracts
- Seikei-Kakou Abstracts
