Transient extensional rheology and the influence of strain history

Ferguson, J.; Hudson, N.E.; Forsyth, J.F.

doi:10.1016/s0377-0257(98)00107-4

Cited by 4 publications

(5 citation statements)

References 8 publications

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“…8), since the elongational viscosity should be lower at higher temperatures. The Instron fiber data in Figure 911–13 is plotted versus strain rate rather than time and it also follows a consistent pattern. The elongational viscosity at a given strain rate increases with increasing Hencky strain, and all the data indicates strain rate thinning behavior, indicating strain hardening and strain rate thinning.…”

Section: Resultsmentioning

confidence: 59%

“…The PE and PS samples and their molecular characteristics were supplied by the Meissner group at Eidgenössische Technische Hochschule‐Zürich (ETH), and the Baird research group of Virginia Polytechnic Institute and State University (VPI). The PIB sample was provided by Dr. Hudson of the University of Strathclyde and has been characterized by other rheologists 10–12. The PIB sample was tested in our laboratory at temperatures of 210, 220, 230, and 240°C.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, it is expected that imposed orientation should increase as any one of the terms in the product increases when the others are held constant. Furthermore, Ferguson et al11, 12 and Odriozola13 predicted that the elongational rheology was dependent upon both the elongational strain rate and time (therefore Hencky strain) and that a surface on a three dimensional plot of elongational viscosity versus elongational strain rate and time could be generated to display this effect. In many devices the Hencky strain increases with process time.…”

Section: Orientation Number Definitionmentioning

confidence: 99%

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Elongational rheology by different methods and orientation number

Collier

Petrovan

Hudson

et al. 2007

J of Applied Polymer Sci

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ABSTRACT:The elongational rheology of polymer melts was measured by the authors using the hyperbolic convergent die technique and the results were compared with the same samples measured using a Meissner type device or an Instron tensile tester. Polyethylene and polystyrene samples were tested at Eidgenö ssische Technische Hochschule-Zü rich or Virginia Polytechnic Institute, and the polyisobutylene was part of a world wide ''Round Robin'' comparison. A modified Weissenberg number, i.e., an Orientation number, is suggested to explain the agreement between techniques for some samples and lack of agreement for others. The Orientation number is the product of Hencky strain, elongational strain rate, and average relaxation time. When it is less than one a relaxation dominant regime results, when greater than one an orientation dominant regime results, and near one a transition occurs. For the hyperbolic convergent die technique, in which the polymers are transversely constrained by the walls, the extrudates in the transition regime have slight surface defects and the pressure fluctuates more than in the other regimes. If the transition occurs after significant time, i.e., lower elongational strain rates, in the free boundary Meissner and Instron devices, the samples apparently experience more relaxation since unconstrained transversely (and perhaps differential thinning) leading to disagreement with the hyperbolic die measurements. The orientation related body forces are magnitudes larger than the shearing forces and cause slip at the wall in the hyperbolic dies in the orientation dominant regime. Even in the relaxation dominant regime, shear near the wall is a minor contributor to the necessary pressure force.

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Section: Resultsmentioning

confidence: 59%

Section: Methodsmentioning

confidence: 99%

Section: Orientation Number Definitionmentioning

confidence: 99%

See 1 more Smart Citation

Elongational rheology by different methods and orientation number

Collier

Petrovan

Hudson

et al. 2007

J of Applied Polymer Sci

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“…53 To obtain the entire rheologic behavior of a given polymer solution at a fixed temperature, a three-dimensional surface must be generated describing extensional viscosity as a simultaneous function of strain rate and degree of strain. 54 Experimentally, the rate and degree of fluid extension are difficult to control independently. 55 For the purpose of studying polymer solutions for EOR, exact measurement of solution extensional viscosities is unachievable.…”

Section: Methodsmentioning

confidence: 99%

Stimuli-Responsive Polymers With Enhanced Efficiency in Reservoir Recovery Processes

McCormick¹,

Hester²

2004

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This sixth and final progress report for DOE Award Number DE-FC26-01BC15317 describes research during the period March 01, 2004 through August 31, 2004 performed at the University of Southern Mississippi on Stimuli Responsive Polymers with Enhanced Efficiency in Reservoir Recovery processes. Significantly, terpolymers that are responsive to changes in pH and ionic strength have been synthesized, characterized, and their solution properties have been extensively examined. Terpolymers composed of acrylamide, a carboxylated acrylamido monomer (AMBA), and a quarternary ammonium monomer (AMBATAC) with balanced compositions of the latter two, exhibit increases in aqueous solution viscosity as NaCl concentration is increased. This increase in polymer coil size can be expected upon injection of this type of polymer into oil reservoirs of moderate-to-high salinity, leading to better mobility control. The opposite effect (loss of viscosity) is observed for conventional polymer systems.

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“…The orientation number proposed represents the amount of orientation occurring in a solution or melt as well as whether or not slip occurs at the die wall 5. Several studies have recently determined that the elongational rheology was dependent on both the elongational strain rate and time 6, 7. In many instances, the Hencky strain increases with process time.…”

Section: Introductionmentioning

confidence: 99%

Orientation of carbon fiber precursors from 1‐butyl‐3‐metylimidazoluim chloride cellulose solutions

Sammons

Collier

Rials

et al. 2012

J of Applied Polymer Sci

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Cellulose/1-butyl-3-methylimidazolium chloride ([Bmim]Cl) solutions were wet spun at varied concentrations, temperatures and draw down ratios using a semi-hyperbolically converging die to produce fibers that were highly oriented and highly crystalline. The orientation number (N OR ) and the Herman's orientation factor (f H ) were compared with the fiber crystallinity. The analysis of the results indicates that the spinning parameters had a significant effect on the fiber properties, especially the orientation factor as well as the orientation number. Therefore, to spin cellulose fibers that would be suitable for carbon fiber precursors, the spinning parameters are a high concentration solution at approximately 90 C and at a medium draw ratio. This would yield fibers with a high orientation number. V C 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 128: 951-957, 2013

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Transient extensional rheology and the influence of strain history

Cited by 4 publications

References 8 publications

Elongational rheology by different methods and orientation number

Elongational rheology by different methods and orientation number

Stimuli-Responsive Polymers With Enhanced Efficiency in Reservoir Recovery Processes

Orientation of carbon fiber precursors from 1‐butyl‐3‐metylimidazoluim chloride cellulose solutions

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