Polymer Bulletin

, Volume 67, Issue 9, pp 1935–1944 | Cite as

Correlation between entry pressure losses and elongation viscosity of polyethylene melts

Original Paper
First Online:
Received:
Revised:
Accepted:

Abstract

The correlation between the entry pressure drop and elongation viscosity during entry converging flow of polymer melts was discussed in this article. The entry pressure drop during extrusion of a low density polyethylene (LDPE) melt and a linear low density polyethylene (LLDPE) melt was measured by means of a capillary rheometer under test conditions with temperature of 170 °C and shear rate varying from 10 to 300 s−1. The results showed that the entry pressure drop increased nonlinearly with an increase of the shear stain rate, and the variation of entry pressure drop of the two melts was close to each other. The melt elongation viscosity of the two resins was estimated using Cogswell equation from the measured entry pressure drop data, and the predictions were compared with the melt extension viscosity measured by using a melt spinning technique published in literature. It was found that the melt extension viscosity from entry converging flow was slightly lower than that from melt spinning technique under the same temperature and extension strain rate.

Keywords

Polymer melt Entry pressure losses Elongation viscosity Extrusion 
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Notes

Acknowledgments

The author would like to thank Dr. L. Zhong from South China University of Technology for his helping in the experimental.

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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  1. 1.School of Mechanical and Automotive EngineeringSouth China University of TechnologyGuangzhouPeople’s Republic of China

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