Skip to main content

Research Repository

Advanced Search

Cross-slot extensional rheometry and the steady-state extensional response of long chain branched polymer melts

Auhl, D.; Hoyle, David M.; Hassell, D.; Lord, T.D.; Mackley, M.R.; Harlen, O.G.; McLeish, T.C.B.

Cross-slot extensional rheometry and the steady-state extensional response of long chain branched polymer melts Thumbnail


Authors

D. Auhl

David M. Hoyle

D. Hassell

T.D. Lord

M.R. Mackley

O.G. Harlen

T.C.B. McLeish



Abstract

Stress-optical measurements at a flow stagnation point in confined geometries such as the cross-slot provide an elegant way to perform extensional testing for polymer melts. This technique is especially useful for samples which have a steady-state that cannot be reached (easily) in standard elongational rheometry, for example, highly branched polymers which show a non-homogeneous deformation that occurs in stretching experiments for Hencky strains above 4. In contrast to filament stretching, the cross-slot provides one point at which steady-state extensional flow may be sustained indefinitely. In this study, a Cambridge multi-pass rheometer [ Coventry, K. D., and M. R. Mackley, J. Rheol. 52, 401–415 (2008) ] is used to generate planar elongational flow in a cross-slot geometry for different polyethylene melts. The experimental results are compared to finite element flow simulations using the multi-mode Pompom constitutive equations. The steady-state elongational viscosity at the stagnation point is computed from the flow-induced stress birefringence and the strain-rate determined from numerical calculations of the flow field. We apply this technique to a range of different branched high- and low-density polyethylene melts. This demonstrates both the effectiveness of this technique and shows how the stress distribution in a complex flow depends on molecular structure. Cross slot extensional rheometry therefore provides a very promising technique for parameterizing molecular constitutive equations for LCB melts.

Citation

Auhl, D., Hoyle, D. M., Hassell, D., Lord, T., Mackley, M., Harlen, O., & McLeish, T. (2011). Cross-slot extensional rheometry and the steady-state extensional response of long chain branched polymer melts. Journal of Rheology, 55(4), 875-900. https://doi.org/10.1122/1.3589972

Journal Article Type Article
Publication Date Jul 1, 2011
Deposit Date Feb 16, 2012
Publicly Available Date Mar 28, 2024
Journal Journal of Rheology
Print ISSN 0148-6055
Electronic ISSN 1520-8516
Publisher American Institute of Physics
Peer Reviewed Peer Reviewed
Volume 55
Issue 4
Pages 875-900
DOI https://doi.org/10.1122/1.3589972

Files

Published Journal Article (2 Mb)
PDF

Copyright Statement
© 2011 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, 55(4): 875-900 and may be found at https://doi.org/10.1122/1.3589972





You might also like



Downloadable Citations