Hawke, LGD, Huang, Q, Hassager, HO et al. (1 more author) (2015) Modifying the pom-pom model for extensional viscosity overshoots. Journal of Rheology, 59. 995. ISSN 0148-6055
Abstract
We have developed a variant of the pom-pom model that qualitatively describes two surprising features recently observed in filament stretching rheometer experiments of uniaxial extensional flow of industrial branched polymer resins: (i) Overshoots of the transient stress during steady flow and (ii) strongly accelerated stress relaxation upon cessation of the flow beyond the overshoot. Within the context of our model, these overshoots originate from entanglement stripping (ES) during the processes of normal chain retraction and branch point withdrawal. We demonstrate that, for a single mode, the predictions of our overshoot model are qualitatively consistent with experimental data. To provide a quantitative fit, we represent an industrial melt by a superposition of several individual modes. We show that a minimal version of our model, in which ES due to normal chain retraction is omitted, can provide a reasonable, but not perfect, fit to the data. With regard the stress relaxation after (kinematically) steady flow, we demonstrate that the differential version of tube orientation dynamics in the original pom-pom model performs anomalously. We discuss the reasons for this and suggest a suitable alternative.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c)2015 by The Society of Rheology, Inc. Reproduced in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mathematics (Leeds) > Applied Mathematics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 15 Jun 2015 15:58 |
Last Modified: | 18 Jan 2018 03:21 |
Published Version: | http://dx.doi.org/10.1122/1.4922060 |
Status: | Published |
Publisher: | American Institute of Physics |
Identification Number: | 10.1122/1.4922060 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:87044 |