A thermodynamic framework for solutions based on the osmotic equilibrium concept - 1: General formulation

Cardoso, M. J. E. M.; Medeiros, José Luiz de

doi:10.1351/pac199466030383

Cited by 4 publications

(18 citation statements)

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“…The proposed model is based on the absolute rate theory of Eyring and co-workers 12-14 and the thermodynamic framework for solutions based on the MacMillan-Mayer level by means of the so-called osmotic equilibrium formulation …”

Section: A New Model For Calculating Viscosity Of Binary Electrolyte ...mentioning

confidence: 99%

“…In the so-called osmotic equilibrium thermodynamic framework (continuous solvent), one can write the appropriate thermodynamic potential for a solution as follows, where T is the absolute temperature, P is the solution pressure, n i is the number of moles of the solute species i , and μ 1 is the chemical potential for the solvent species 1. We can also define the intensive (per mole of solute) thermodynamic potential as 28 …”

Section: A New Model For Calculating Viscosity Of Binary Electrolyte ...mentioning

confidence: 99%

“…One must bear in mind that appropriate modifications of Eyring's absolute rate theory must be performed to consider the solvent as a continuous medium, as considered in the Debye−Hückel theory. This is accomplished by means of the so-called osmotic-pressure framework for solutions. , …”

Section: Introductionmentioning

confidence: 99%

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A Debye−Hückel Model for Calculating the Viscosity of Binary Strong Electrolyte Solutions

Esteves

Cardoso

Barcia

2001

Ind. Eng. Chem. Res.

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In this article we present a new model for correlating dynamic viscosity of binary strong electrolyte solutions. The proposed model is based on Eyring's absolute rate theory and the Debye−Hückel model for calculating the excess (electrostatic) free energy of activation of the viscous flow. In the present model we consider that the free energy of activation of the viscous flow as being the same as the appropriate thermodynamic free energy used for calculating equilibrium properties of the electrolyte solution. Modifications of Eyring's absolute rate theory must be performed to take into account the solvent as a continuous medium, as considered in the Debye−Hückel theory. This is accomplished by means of the osmotic-pressure framework for solutions. In this framework one adopts a thermodynamic free energy, which is considered as a function of the absolute temperature, pressure, number of moles of the solute species, and chemical potential of the solvent. The proposed model contains two adjustable parameters that have been fitted by means of experimental viscosity data of the literature. The total number of 21 binary electrolyte systems (at 0.1 MPa and 25 °C) with different solvents (water, methanol, ethanol, and 1-butanol) have been studied. The calculated viscosity values are in good agreement with the experimental ones. The overall average mean relative standard deviation is 0.52%.

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Section: A New Model For Calculating Viscosity Of Binary Electrolyte ...mentioning

confidence: 99%

Section: A New Model For Calculating Viscosity Of Binary Electrolyte ...mentioning

confidence: 99%

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A Debye−Hückel Model for Calculating the Viscosity of Binary Strong Electrolyte Solutions

Esteves

Cardoso

Barcia

2001

Ind. Eng. Chem. Res.

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“…We would remark that the deviations between the calculated values and the experimental viscosity values were smaller than the experimental error (~ up to 10%) [26,32,[47][48][49]. As mentioned before, this model is based on the absolute rate theory of Eyring [18][19][20], and on the solution theory of McMillan-Mayer [27][28][29] by means of the so-called osmotic equilibrium formulation [30,31] . According to this model, the expression for calculation of the viscosity of a polymer solution is given as follows [26,32]:…”

Section: Resultsmentioning

confidence: 99%

“…In a previous paper [26], the authors presented a model based on the absolute rate theory of Eyring [18][19][20] and on the solution theory of McMillan-Mayer [27][28][29][30][31] for calculating the rheological behavior of nonnewtonian polymer solutions. This model presents an explicit shear stress dependence of the viscosity of the solution and was applied to aqueous solutions of just one polyethylene glycol (PEG) molecular weight.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Modeling of the Rheological Behavior of PEG Aqueous Solutions as a Function of the Solute Molecular Weight and Shear Stress, at 298.15 K and 0.1 MPa

Cruz¹

2013

J. Appl. Sol. Chem. Model.

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This work presents a study of the influence of the molecular weight on the thermodynamic modeling of the viscosity of non-newtonian polymer solutions. The employed model is based on the absolute rate theory of Eyring and on the solution theory of McMillan-Mayer. The Soave-Redlich-Kwong equation of state was adopted for the calculation of the excess molar McMillan-Mayer free energy derived from the osmotic pressure of the solution. The model presents parameters that take account separately the different possibilities of interaction in the macromolecular environment. As the tertiary structure of a polymer molecule can be affected by applied shear stress, only the parameters related with the intramolecular interactions are dependent of the shear stress. The experimental rheological curves for different molecular weights of polyethylene glycol aqueous solutions have been measured at several concentrations, within the whole polymer solubility range, at 298.15 K and 0.1 MPa. The dependence on the molecular weight for all parameters of the model was analyzed and characterized. The dependence of the shear sensitive parameters on the shear stress was also studied.

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Model for Calculating the Viscosity of Non-Newtonian Aqueous Solutions of Poly(ethylene glycol) 6000 at 313.15 K and 0.1 MPa

Cruz

Martins

Esteves

et al. 2005

Ind. Eng. Chem. Res.

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In this work, a model for calculating the dynamic viscosity of polymer solutions was developed. The model is based on the Eyring absolute rate theory and on the solution theory of McMillan-Mayer. An equation of state is used for the calculation of the solution osmotic pressure and, thus, the excess molar McMillanMayer free energy. The final expression shows an explicit dependence between the viscosity of the polymer solution and the applied shear stress. The proposed model contains three terms. The first term describes the viscosity of an ideal polymer solution. The second term takes into account non-Newtonian behavior of the polymer solution. Finally, the third term represents the deviation from the thermodynamic ideal behavior. The whole model presented five adjustable parameters, with two of them also considered as being a function of the applied shear stress. To test the proposed model, we have measured experimental rheological data for poly(ethylene glycol) aqueous solutions (nominal molecular weight 6000 g/mol) for nine different polymer concentrations, at different shear rates, at 313.15 K and 0.1 MPa. The proposed model has been used for correlating the experimental viscosity data of these polymer solutions at different values of the applied shear stress and polymer concentration. It has been found that the agreement between the experimental and calculated values is within the experimental error.

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A thermodynamic framework for solutions based on the osmotic equilibrium concept - 1: General formulation

Abstract: Abstract

Cited by 4 publications

References 1 publication

A Debye−Hückel Model for Calculating the Viscosity of Binary Strong Electrolyte Solutions

A Debye−Hückel Model for Calculating the Viscosity of Binary Strong Electrolyte Solutions

Thermodynamic Modeling of the Rheological Behavior of PEG Aqueous Solutions as a Function of the Solute Molecular Weight and Shear Stress, at 298.15 K and 0.1 MPa

Model for Calculating the Viscosity of Non-Newtonian Aqueous Solutions of Poly(ethylene glycol) 6000 at 313.15 K and 0.1 MPa

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