The effect of temperature and type of physical foaming agent (HCFC-142b, n-pentane, and carbon dioxide) on the shear viscosity have been investigated for various types of polyolefin resins (PP, LLDPE, and HDPE). The viscosity changes have been monitored using a commercial on-line process control rheometer mounted on a twin-screw extruder.
A plasticization index, based on the respective molecular weights of the foaming agent and the repeat unit of the polymer, is proposed. Comparison with an amorphous polymer, namely polystyrene, is also made for mixtures using the same physical foaming agents.
Get full access to this article
View all access options for this article.
References
1.
1. Gendron, R. and Daigneault, L.E. (2000). In: Lee, S.-T. (ed.), Rheology of Thermoplastic Foam Extrusion Process in Foam Extrusion, Principles and Practice, Chap. 3, pp. 35–80, Technomic Publi. Co., Lancaster, PA .
2.
2. Dey, S.K., Jacob, C. and Biesenberger, J.A. (1994). Effect of Physical Blowing Agents on Crystallization Temperature of Polymer Melts , SPE Antec Tech. Papers, 40: 2197–2198 .
3.
3. Royer, J.R., Gay, Y.J., Adam, M., DeSimone, J.M. and Khan, S.A. (2002). Polymer Melt Rheology with High-Pressure CO2 Using a Novel Magnetically Levitated Sphere Rheometer , Polymer, 43(8): 2375–2383 .
4.
4. Kwag, C., Manke, C.W. and Gulari, E. (1999). Rheology of Molten Polystyrene with Dissolved Supercritical and Near-Critical Gases , J. Polym. Sci: Part B: Polym. Phys., 37(19): 2771–2781 .
5.
5. Lee, M., Park, C.B. and Tzoganakis, C. (1999). Measurements and Modeling of PS/Supercritical CO2 Solution Viscosities , Polym. Eng. Sci., 39(1): 99–109 .
6.
6. Paquet, A.N. and Vo, C.V. (1999). New STYROFOAM TM Brand Extruded Polystyrene Foam Blown from Carbon Dioxide , In: Proceedings of SPE Retec Foams’99, October 19–20, 1999, Parsippany, NJ, pp. 5–11 .
7.
7. Park, C.P. (1999). An Overview of Polyolefin Foams – Opportunities, Challenges and Recent Developments , In: Proceedings of SPE Retec Foams’99, October 19–20, 1999, Parsippany, NJ, pp. 61–72 .
8.
8. Han, C.D. and Ma, C.-Y. (1983). Rheological Properties of Mixtures of Molten Polymer and Fluorocarbon Blowing Agent. I. Mixtures of Low-Density Polyethylene and Fluorocarbon Blowing Agent , J. Appl. Polym. Sci., 28(2): 831–850 .
9.
9. Ma, C.-Y. and Han, C. D. (1982). Measurement of the Viscosities of Mixtures of Thermoplastic Resin and Fluorocarbon Blowing Agent , J. Cell. Plas., 18: 361–370 .
10.
10. Areerat, S., Nagata, T. and Ohshima, M. (2002). Measuring and Modeling of Viscosity Depression Induced by CO2 Dissolution , In: Conference Proceeding PPS-18, June 16–20, 2002, Guimaraes, Portugal, Paper 342.
11.
11. Gendron, R., Huneault, M., Tatibouët, J. and Vachon, C. (2002). Foam Extrusion of Polystyrene Blown with HFC-134a , Cell. Polym., 21(5): 315–341 .
12.
12. Sato, Y., Iketani, T., Takishima, S. and Masuoka, H. (2000). Solubility of Hydrofluorocarbon (HFC-134a, HFC-152a) and Hydrochlorofluorocarbon (HCFC-142b) Blowing Agents in Polystyrene , Polym. Eng. Sci., 40(6): 1369–1375 .
13.
13. Gendron, R., Daigneault, L. and Caron, L.M. (1999). Rheological Behavior of Mixtures of Polystyrene with HCFC 142b and HFC-134a , J. Cell. Plas., 35(3): 221–246 .
14.
14. Ferry, J.D. (1970). Viscoelastic Properties of Polymers, Wiley, New York .
15.
15. Chow, T.S. (1980). Molecular Interpretation of the Glass Transition Temperature of Polymer-Diluent Systems , Macromolecules, 13(12): 362–364 .
16.
16. Wood-Adams, P. and Costeux, S. (2001). Thermorheological Behavior of Polyethylene: Effects of Microstructure and Long Chain Branching , Macromolecules, 34(18): 6281–6290 .
17.
17. Chiou, J.S., Barlow, J.W. and Paul, D.R. (1985). Plasticization of Glassy Polymers by CO2 , J. Appl. Polym. Sci., 30(6): 2633–2642 .
