Rotary Clamp in Uniaxial and Biaxial Extensional Rheometry of Polymer Melts

Meissner, J.; Raible, T.; Stephenson, S. E.

doi:10.1122/1.549612

Cited by 104 publications

(11 citation statements)

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“…A transitory steady domain was also observed in creep with PDMS in the pioneering work on LSF by Chatraei et al. (1981) or with polyisobutanol at a constant strain rate by Meissner et al. (1981) using the rotary clamps technique.…”

Section: Discussionmentioning

confidence: 81%

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Biaxial Extension of Wheat Flour Doughs: Lubricated Squeezing Flow and Stress Relaxation Properties

Launay¹,

Michon

2008

Journal of Texture Studies

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Biaxial extension in lubricated squeezing flow (LSF) was first developed for molten polymers and transferred to the study of wheat flour dough (1986). Depending on geometry, LSF is performed at constant surface or at constant volume. Most of the measurements have been carried out with a mechanical testing machine at constant crosshead speed and constant surface. An empirical power law equation relates stress and strain rate at constant strain and, at a given strain rate, there is an approximate exponential stress-strain relationship from which a parameter named "strain hardening" is derived and tentatively related to resistance of dough membranes against premature rupture. This exponential relationship does not seem to hold in other experimental conditions, particularly at constant volume. Stress relaxation following lubricated compression might also allow the study of dough viscoelastic properties. The role of unsteady regime, testing conditions and dough compressibility is finally discussed. PRACTICAL APPLICATIONSExtensional flow properties of polymers have long been recognized as important for understanding their processing behaviors and the experimental measurement of these properties has been the subject of many studies. The relevance of biaxial extension properties to dough behavior in baking technology was at the origin of the Alveograph developed by Chopin more then 1 Corresponding

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Section: Discussionmentioning

confidence: 81%

“…For example, biaxial extension of molten polymers is relevant to film blowing (Dealy and Wissbrun 1999). In order to obtain biaxial extension, a sheet of polymer may be stretched along its plane; this has been done by Meissner et al. (1981) with a prototype equipment based on a sophisticated system of rotary clamps.…”

Section: Introductionmentioning

confidence: 99%

Biaxial Extension of Wheat Flour Doughs: Lubricated Squeezing Flow and Stress Relaxation Properties

Launay¹,

Michon

2008

Journal of Texture Studies

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“…A number of measurement techniques have been introduced to determine these rheometrical properties, where each technique is known to have its advantages and disadvantages; see the detailed discussion in Macosko [1] and Morrison [2]. For example, this would include filament stretching, as in the apparatus devised by Sridhar et al [3] for uniaxial extension, the apparatus of Meissner [4][5][6] for biaxial and planar extension, lubricated squeezing [7] for biaxial extension, use of contraction flow [8,9], the stagnation point using a four roll mill [9], and the cross-slot apparatus [10][11][12]. In spite of this position, still there exist relatively few reliable data-sets for such contributions to the friction coefficient term.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of viscoelastic fluids in cross-slot devices

Puangkird

Belblidia

Webster

2009

Journal of Non-Newtonian Fluid Mechanics

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“…However, a feasibility study of the biaxial extensional rheology of polymer melts is still a challenge because of the complex biaxial extensional geometry. 46 One idea to assess the extensional properties of polymer melts is to measure the uniaxial extensional properties of a polymer melt and evaluate these data using the MSF model as a molecular constitutive equation. With this method, we are able to quantify the strain hardening, which is also a dominant factor in biaxial deformation, using SAOS data and two nonlinear material parameters, β and f max , which could be correlated to the number of branches.…”

Section: Resultsmentioning

confidence: 99%

Influence of molecular structure on the foamability of polypropylene: Linear and extensional rheological fingerprint

Bahreini

Aghamiri

Wilhelm

et al. 2017

Journal of Cellular Plastics

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The foaming structure and rheological properties of four different isotactic homopolypropylenes with various molecular weights and an isotactic long chain branched polypropylene were investigated to find a suitable rheological fingerprint for PP foams. The molecular weight distribution and thermal properties were measured using GPC-MALLS and differential scanning calorimetry, respectively. Small amplitude oscillatory shear data and uniaxial extensional experiments were analyzed using the frameworks of van Gurp-Palmen plot (d vs. jG*j) and the molecular stress function model, respectively. These analyses were used to find a correlation between the molecular structure, rheological properties and foaming structures of linear and long chain branching polypropylenes. Two linear viscoelastic characteristics, jG*j at d ¼ 60 and j*j at o ¼ 5 rad/s were used as criteria for foamability of these polymers, where decreasing of both parameters by increasing the long chain branching content results in smaller cell size and higher cell density. The molecular stress function model was able to quantify the strain hardening properties of long chain branching blends using small amplitude oscillatory shear data and two nonlinear material parameters, 1 2.2 and 1 f 2 max 600, where the minimum and maximum values of these parameters belong to the linear and long chain branched polypropylene, respectively. Increasing the long chain branched polypropylene content of the PP blends increased strain hardening, and therefore improved the foaming characteristics significantly by suppressing the

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Rotary Clamp in Uniaxial and Biaxial Extensional Rheometry of Polymer Melts

Cited by 104 publications

References 0 publications

Biaxial Extension of Wheat Flour Doughs: Lubricated Squeezing Flow and Stress Relaxation Properties

Biaxial Extension of Wheat Flour Doughs: Lubricated Squeezing Flow and Stress Relaxation Properties

Numerical simulation of viscoelastic fluids in cross-slot devices

Influence of molecular structure on the foamability of polypropylene: Linear and extensional rheological fingerprint

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