On the predictive/fitting capabilities of the advanced differential constitutive equations for branched LDPE melts

Pivokonský, Radek; Zatloukal, Martin; Filip, Petr

doi:10.1016/j.jnnfm.2006.01.001

Cited by 34 publications

(48 citation statements)

References 16 publications

(23 reference statements)

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“…The experimental data analyzed are those of Pivokonsky et al [1]. The rheology of two highly branched LDPE materials widely used in the film blowing industry (LDPE Escorene LD165BW1, Exxon, USA, and LDPE Bralen RB0323, Slovnaft, Slovakia) was investigated.…”

Section: Experimental Datamentioning

confidence: 99%

“…The uniaxial extensional viscosity was measured with the ARES 2000 rheometer equipped with the SER Universal Testing Platform (SER-HV-A01 model) from Xpansion Instruments [24][25][26]. For more detailed description of the experiments see Pivokonsky et al [1].…”

Section: Experimental Datamentioning

confidence: 99%

“…Constitutive equations of the differential type have been used to model rheology of such complex topologies in different types of deformations (see [21][22][23]). Pivokonsky et al [1] presented experimental data in shear and elongation of two highly branched film-blowing grades of LDPE, and analyzed their data successfully by use of three different advanced differential constitutive equations, the so-called XPP model, the PTT-XPP model and the modified Leonov model. It is well known that the severe drawback of constitutive equations of the differential type inheres in a large number of nonlinear parameters needed to get quantitative agreement between predictions and experimental data.…”

Section: Introductionmentioning

confidence: 99%

“…Due to the completeness of the data set obtained by Pivokonsky et al [1] and the very broad experimental window comprising many decades of deformation rates, it is the objective of the present contribution to demonstrate the modelling capabilities of the MSF model in shear and elongational flow, using the same three nonlinear material parameters for all relaxation modes.…”

Section: Introductionmentioning

confidence: 99%

“…Experimental data of two low-density polyethylene (LDPE) melts at 200°C for both shear flow (transient and steady shear viscosity as well as steady first normal stress coefficient) and elongational flow (transient and steady-state elongational viscosity) as published by Pivokonsky et al [1] were analyzed by use of the Molecular Stress Function (MSF) model for broadly distributed, randomly branched molecular structures. For quantitative modeling of melt rheology in both types of flow and in a very wide range of deformation rates, only three nonlinear viscoelastic material parameters are needed: While the rotational parameter, 2 a , and the structural parameter, E , are found to be equal for the two melts considered, the melts differ in the parameter 2 max f describing maximum stretch of the polymer chains.…”

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confidence: 99%

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Rheological Characterization and Constitutive Modeling of Two LDPE Melts

Rolón-Garrido¹,

Pivokonský²,

Filip³

et al. 2009

AIP Conference Proceedings

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Abstract. Experimental data of two low-density polyethylene (LDPE) melts at 200°C for both shear flow (transient and steady shear viscosity as well as steady first normal stress coefficient) and elongational flow (transient and steady-state elongational viscosity) as published by Pivokonsky et al. [1] were analyzed by use of the Molecular Stress Function (MSF) model for broadly distributed, randomly branched molecular structures. For quantitative modeling of melt rheology in both types of flow and in a very wide range of deformation rates, only three nonlinear viscoelastic material parameters are needed: While the rotational parameter, 2 a , and the structural parameter, E , are found to be equal for the two melts considered, the melts differ in the parameter 2 max f describing maximum stretch of the polymer chains.

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Section: Experimental Datamentioning

confidence: 99%

Section: Experimental Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Rheological Characterization and Constitutive Modeling of Two LDPE Melts

Rolón-Garrido¹,

Pivokonský²,

Filip³

et al. 2009

AIP Conference Proceedings

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A single‐mode rheological model for steady flows of polymer melts

Yang

Liang

Wang

2012

J of Applied Polymer Sci

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The steady shear viscosity (g s ), the steady first normal stress coefficient (W 1 ), the steady second normal stress coefficient (W 2 ), and extensional viscosity (g e ) are four important parameters for polymer melts during polymer processing. In this article, we propose a stress and rate-dependent function to describe creation and destruction of polymer junctions. Moreover, we also introduce a movement expression to describe nonaffine movement of network junctions. Based on network theory, a nonaffine single-mode rheological model is presented for the steady flow of polymeric melts, and the equations of g s , W 1 , W 2 , and g e are derived from the model accordingly. Furthermore the dependences of g s and g e on model parameters are discussed for the model. Without a complex statistical simulation, the single-mode model with four parameters yields good quantitative predictions of the steady shear and extensional flows for two low density polyethylene melts reported from previous literature in very wide range of deformation rates.

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Prediction of the Viscoelastic Behavior of Low‐Density Polyethylene Produced in High‐Pressure Tubular Reactors

Pladis

Meimaroglou

Kiparissides

2015

Macro Reaction Engineering

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In the open literature, there is a lack of comprehensive predictive models that can provide detailed information on the distributed molecular properties of LDPE (e.g bivariate molecular weight-long-chain distribution, seniority-priority long-chain branching distributions, etc.) produced in a high-pressure process. To address this problem, Meimaroglou and Kiparissides (2010) developed a novel kinetic-molecular topology Monte Carlo (MC) algorithm to predict the exact molecular architecture of nonlinear polyethylene chains. In the present paper, the molecular information obtained from the kinetic-topology MC algorithm is introduced into a comprehensive rheological model, the so-called ''branch on branch'' model of Das et al. (2006), to predict the rheological behavior of the LDPE melt in a high-pressure ethylene polymerization tubular reactor. The model uses an ensemble of branched polymer chains generated by the kinetic-chain topology MC algorithm to calculate several important viscoelastic properties, including the viscosity-shear rate curve, the storage and loss moduli, etc. The predictive capabilities of the new proposed computational approach, combining the solutions of kinetic, chain topology, and rheology models, are fully assessed via a direct comparison of model predictions with available experimental measurements on the molecular weight distribution, longchain branching, and linear viscoelastic properties of two LDPE grades produced in industrial-scale reactors.

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On the predictive/fitting capabilities of the advanced differential constitutive equations for branched LDPE melts

Cited by 34 publications

References 16 publications

Rheological Characterization and Constitutive Modeling of Two LDPE Melts

Rheological Characterization and Constitutive Modeling of Two LDPE Melts

A single‐mode rheological model for steady flows of polymer melts

Prediction of the Viscoelastic Behavior of Low‐Density Polyethylene Produced in High‐Pressure Tubular Reactors

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