On nonlinear effects in the extensional flow of polymeric liquids

Leonov, A. I.; Prokunin, A. N.

doi:10.1007/bf01332368

Cited by 34 publications

(10 citation statements)

References 16 publications

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“…(26) agrees completely with the case of homogeneous extension at given constant force considered in [11]; this was the main reason for introducing the variables (23).…”

Section: E = X 2 -X -I + V ( Y 2 -Y -L )supporting

confidence: 65%

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On the stretching and swelling of an elastic liquid extruded from a capillary die

Leonov¹,

Prokunin

1984

Rheol Acta

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A theoretical model for calculating the profile of a polymer jet extruded from a circular die and stretched by an axial force is elaborated. The model exploits the idea of matching the solutions for the polymer flow inside and outside the capillary by equating the elastic energy flux at the die outlet. The rheological equations used to obtain the two solutions have been previously tested in many situations. Comparison of the results of computations made according to the theoretical model with those of some special experiments revealed satisfactory agreement.

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“…(26) agrees completely with the case of homogeneous extension at given constant force considered in [11]; this was the main reason for introducing the variables (23).…”

Section: E = X 2 -X -I + V ( Y 2 -Y -L )supporting

confidence: 65%

“…Proposed in such a way this problem coincides exactly with that considered in [11] for the homogeneous…”

Section: ~(T) = [E(t)] -1/2 ~(T) _ ~ E(t') Dt'supporting

confidence: 51%

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On the stretching and swelling of an elastic liquid extruded from a capillary die

Leonov¹,

Prokunin

1984

Rheol Acta

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“…For the purpose of the study we employ the slightly inhomogeneous approach [29] with the assumption that the averaged description of the cross-section variation of the extrudate is approximately true beginning with the outlet of the capillary die, as supposed in [30]. Since the extrudate is free from stresses (its total axial force is equal to zero), we have…”

Section: Distortions On the Extrudate Surface Due To Shear Oscillatiomentioning

confidence: 99%

A linear model of the stick-slip phenomena in polymer flow in rheometers

Leonov¹

1984

Rheol Acta

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A linear approach was employed for the qualitative theoretical study of the stick-slip phenomena in polymer flows in rheometers. For this purpose, the familiar three-constant rheological equation and a linear wall friction law (i.e. wall stress -slip velocity dependence) were used with some additional hypotheses about the onset of the stick-slip behaviour. The friction law used was derived from a crude molecular approach. On the basis of these equations the inertialess stickslip behaviour of a viscoelastic liquid flowing through a capillary at a constant flow rate was considered. To be able to describe some transient phenomena in this problem, inertial effects (as an example) were taken into account. Furthermore, the distortions on the extrudate surface due to the slip phenomena inside the capillary were described theoretically within the framework of a linear approximation. In the final part of the study the possibility of rapid stochastization was discussed for rotational stick-slip flow of polymers in a cone-plate rheometer.

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“…The Leonov constitutive Equation (CE) and its variations have been successfully employed to model different types of flows including oscillatory shear, stress relaxation, steady shear, uniaxial extension, biaxial extension, startup shear, entrance flow, planar flow, and squeezing flow for both unfilled 28,29,38–65 and particle‐filled systems 28,29,37,66–74 . It has even been successfully employed to model the complex flow behavior encountered in injection molding for unfilled polymers 75,76 …”

Section: Leonov Constitutive Equationmentioning

confidence: 99%

The nonlinear stress relaxation behavior after a step shear of star‐shaped styrene‐butadiene rubber filled with precipitated silica: Experiment and simulation

Pole

Isayev

2020

J of Applied Polymer Sci

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The nonlinear stress relaxation behavior after a step shear strain of star‐shaped SSBR/silica compounds containing 21 vol% filler of various surface areas was measured and simulated using constitutive equations. A styrene‐butadiene rubber (SBR) gum and SBR filled with silica having BET surface areas of 55, 135, 160, and 195 m2/g were used. Relaxation modulus behavior of the filled compounds was found to be dependent on surface area. Specifically, stress relaxation tests indicated that an increase in surface area led to increase in values of relaxation moduli in both the linear and nonlinear regimes. The time‐dependent relaxation modulus exhibited a plateau at long times of relaxation in compounds containing silica of high surface area. Additionally, good time‐strain superpositions were achieved for all samples at intermediate times of relaxation, and the strain‐dependent damping function decreased with filler surface area. The constitutive equations proposed by Leonov and Simhambhatla and Leonov, modified to include multimodal relaxation of the particle network, were used to predict the time evolution of the relaxation modulus in the nonlinear regime for all samples. The simulations provided good results for the SBR gum for all tested strain levels. Also, in the compounds filled with silica, both models satisfactorily described the experimental observation in the nonlinear regime at low strain levels. However, at higher strain levels, due to a possible slip effect, the simulations overpredicted measured values of the relaxation moduli, thus leading to only qualitative predictions of the observed behavior. It is also possible that neither model accurately captured the floc rupture kinetics of these complex rubber compounds.

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On nonlinear effects in the extensional flow of polymeric liquids

Cited by 34 publications

References 16 publications

On the stretching and swelling of an elastic liquid extruded from a capillary die

On the stretching and swelling of an elastic liquid extruded from a capillary die

A linear model of the stick-slip phenomena in polymer flow in rheometers

The nonlinear stress relaxation behavior after a step shear of star‐shaped styrene‐butadiene rubber filled with precipitated silica: Experiment and simulation

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