The effect of viscoelasticity on stress fields within polyethylene melt flow for a cross-slot and contraction–expansion slit geometry

Hassell, David; Auhl, Dietmar; McLeish, Tom; Mackley, M. R.

doi:10.1007/s00397-008-0261-8

Cited by 31 publications

(26 citation statements)

References 40 publications

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“…Some work along this line has been done for describing large amplitude oscillatory shear experiments [Hoyle (2010)]. These coarse-grained pompom modes in turn can be used to predict the flow properties in more complex geometries [Hassell et al (2008)]. …”

Section: Discussionmentioning

confidence: 99%

Numerical prediction of nonlinear rheology of branched polymer melts

Das

Read

Auhl

et al. 2014

Journal of Rheology

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. SynopsisIn a recent short communication [Read, D. J. et al., Science 333, 1871(2011], we showed that a computational scheme can describe the nonlinear flow properties for a series of industrial lowdensity polyethylene (LDPE) resins starting from the molecular architecture. The molecular architecture itself is determined by fitting parameters of a reaction kinetics model to average structural information obtained from gel-permeation chromatography and light scattering. Flow responses of these molecules in transient uniaxial extension and shear are calculated by mapping the stretch and orientation dynamics of the segments within the molecules to effective pom-pom modes. In this paper, we provide the details of the computational scheme and present additional results on a LDPE and a high-density polyethylene resin to illustrate the dependence of segmental maximum stretch variables on the flow rate. V C 2014 The Society of Rheology.

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Section: Discussionmentioning

confidence: 99%

Numerical prediction of nonlinear rheology of branched polymer melts

Das

Read

Auhl

et al. 2014

Journal of Rheology

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“…The linear rheology has been reported by Hassell et al (2008). The nonlinear rheology in extensional flow has been reported by Hoyle et al (2013) using three different rheometers including the FSR [Bach et al (2003)].…”

Section: Methodsmentioning

confidence: 93%

Modifying the pom-pom model for extensional viscosity overshoots

Hawke¹,

Huang²,

Hassager³

et al. 2015

Journal of Rheology

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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. V C 2015 The Society of Rheology.[http://dx

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“…rudy.valette@mines-paristech.fr tions were validated in strong and/or complex flows in many recent studies [7][8][9][10][11][12][13][14][15]. However, the data of Bach et al [16] have shown an unexpected elongational thinning behaviour in "strong" elongational flows (where the strain rate was larger than the inverse Rouse relaxation time).…”

Section: Introductionmentioning

confidence: 89%