Theoretical prediction and experimental measurement of isothermal extrudate swell of monodisperse and bidisperse polystyrenes

Robertson, Ben; Thompson, Richard L.; McLeish, Tom C.B.; Robinson, Ian

doi:10.1122/1.4995603

Theoretical prediction and experimental measurement of isothermal extrudate swell of monodisperse and bidisperse polystyrenes

Robertson, Ben; Thompson, Richard L.; McLeish, Tom C.B.; Robinson, Ian

Authors

Ben Robertson

Dr Richard Thompson r.l.thompson@durham.ac.uk
Associate Professor

Tom C.B. McLeish

Ian Robinson

Abstract

This paper describes the theoretical prediction, finite element simulation, and experimental studies of extrudate swell in monodisperse and bidisperse polystyrenes. We present a molecular approach to understanding extrudate swell using the tube-model-based Rolie-Poly constitutive equation within a Lagrangian finite element solver. This yields theoretical predictions of swelling which show a close universality: The molecular weight dependence of the swelling can be removed when the flow speed is scaled by the Rouse Weissenberg number. The roles that both chain orientation and stretch play in determining extrudate swell are clearly identifiable from plots of swelling ratio against each Weissenberg number. We also present isothermal extrusion experiments on the same polymers and can obtain good predictions well into the strong chain stretching regime. The predictions for swelling ratios match those from experiments up to Rouse Weissenberg numbers of ∼7, above which swelling is overpredicted by the Rolie-Poly equation.

Citation

Robertson, B., Thompson, R. L., McLeish, T. C., & Robinson, I. (2017). Theoretical prediction and experimental measurement of isothermal extrudate swell of monodisperse and bidisperse polystyrenes. Journal of Rheology, 61(5), 931-945. https://doi.org/10.1122/1.4995603

Journal Article Type	Article
Acceptance Date	Jul 26, 2017
Online Publication Date	Jul 26, 2017
Publication Date	Sep 1, 2017
Deposit Date	Jul 31, 2017
Publicly Available Date	Jul 31, 2017
Journal	Journal of Rheology
Print ISSN	0148-6055
Electronic ISSN	1520-8516
Publisher	American Institute of Physics
Peer Reviewed	Peer Reviewed
Volume	61
Issue	5
Pages	931-945
DOI	https://doi.org/10.1122/1.4995603

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Copyright Statement
© 2017 The Society of Rheology. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of rheology, 61(5): 935-945 and may be found at https://doi.org/10.1122/1.4995603