NELF model prediction of the infinite dilution gas solubility in glassy polymers

Angelis, Maria Grazia De; Sarti, Giulio Cesare; Doghieri, Ferruccio

doi:10.1016/j.memsci.2006.11.044

Cited by 74 publications

(117 citation statements)

References 67 publications

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“…The results of this sensitivity analysis agree with previous literature reports 12,28 , which suggest that, in the limit of infinite dilution, the approximation of As shown in Table 3, the lattice fluid parameters of TR samples reflect the more rigid structure of these polymers and the different size and distribution of free volume elements compared to the HAB-6FDA polyimide. For example, the value of T* increases with increasing degree of thermal conversion.…”

Section: Estimation Of Lattice Fluid Parameters For Hab-6fda and Tr-ssupporting

confidence: 89%

“…In this procedure, the polymer characteristic lattice fluid parameters, T*, p* and *, were treated as fitting parameters and adjusted to the experimental sorption data, while the polymer-penetrant interaction parameter, 12 k , was set equal to zero 12 . Since sorption data for polar or halogenated penetrants are not included in the fitting procedure, assuming 12 k = 0 is a reasonable approximation 12,28 .…”

Section: Estimation Of Lattice Fluid Parameters For Hab-6fda and Tr-smentioning

confidence: 99%

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Nonequilibrium Lattice Fluid Modeling of Gas Solubility in HAB-6FDA Polyimide and Its Thermally Rearranged Analogues

et al. 2016

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For the first time, a theoretical analysis of gas sorption, based on the non-equilibrium lattice fluid (NELF) model, in chemically-imidized HAB-6FDA polyimide and its thermally rearranged analogs is presented. Due to the inaccessibility of pVT data in the rubbery region, the characteristic lattice fluid parameters of the polymers considered in this study were obtained from a collection of infinite dilution solubility data at multiple temperatures. Hydrogen, nitrogen and methane sorption isotherms at 35°C were fit to the NELF model using one adjustable parameter, i.e., the polymer-penetrant binary interaction parameter, 12 k . The optimal value of 12 k for each polymer-penetrant pair was used to predict hydrogen, nitrogen and methane sorption isotherms at other temperatures and at pressures up to 6 MPa. For carbon dioxide, a second adjustable parameter, the swelling coefficient, was introduced to account for sorption-induced matrix dilation. The ideal solubility-selectivity is also predicted for several gas pairs. The increase in gas sorption in thermally rearranged samples relative to their polyimide precursor is essentially due to entropic effects, i.e., to the increase in non-equilibrium fractional free volume during thermal rearrangement.

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Section: Estimation Of Lattice Fluid Parameters For Hab-6fda and Tr-ssupporting

confidence: 89%

Section: Estimation Of Lattice Fluid Parameters For Hab-6fda and Tr-smentioning

confidence: 99%

Nonequilibrium Lattice Fluid Modeling of Gas Solubility in HAB-6FDA Polyimide and Its Thermally Rearranged Analogues

et al. 2016

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“…This result is relevant, as the procedure proposed in this study allows a completely predictive estimation of hydrogen solubility at À 20, À 10, 0, 10, 20, 50 and 70 1C, once the sole fitting parameter Ψ has been optimized on the experimental sorption data at 35 1C. Remarkably, as we will see [43] later, this modeling approach allows an accurate prediction of He/H 2 solubility selectivity with one adjustable parameter only. Interestingly, at each temperature, the mean field polymerpenetrant interaction is weaker in perfluorinated Teflon s AF2400 (Ψ $ 0.97) which due to the presence of bulky perfluorinated moieties, displays a high free volume and, in turn, a low cohesive energy density (CED).…”

Section: Hydrogen Sorption Isothermsmentioning

confidence: 77%

Predictive calculation of hydrogen and helium solubility in glassy and rubbery polymers

Galizia

Smith

Sarti

et al. 2015

Journal of Membrane Science

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a b s t r a c tHydrogen sorption isotherms in selected glassy and rubbery polymers, available over a wide range of temperatures ( À 20 to 70 1C) and pressures (0-60 atm) have been modeled and correlated using equilibrium and non-equilibrium thermodynamic models based on the lattice fluid theory. A good representation of the experimental data can be obtained for the systems considered over the whole range of pressures and temperatures inspected by using just one fitting parameter, under the fundamental assumption that hydrogen behaves as a non-swelling penetrant. The theoretical estimates of infinite dilution solubility coefficients are in excellent agreement with the experimental data. Remarkably, the model analysis allows a reliable estimate of the isosteric heat of sorption and its dependence on the hydrogen concentration over the whole range of pressures considered. A similar theoretical analysis has been performed by considering the helium sorption data available at 35 1C for a series of polymers considered for membrane-based gas separations. Finally, He/H 2 solubility-selectivity at 35 1C has been correctly predicted: as expected, the glassy Teflon s AF-series perfluorinated copolymers display a higher He/H 2 solubility selectivity compared to the hydrocarbon-based polymers.

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“…17 The NELF model is able to represent the solubility of gases and vapors in amorphous glassy polymers; the lattice fluid model is combined with the simple transport model, as done previously by others. [20][21][22][23][24][25][26][27] The diffusivity of the penetrants has to be analyzed too and described by an appropriate transport model. The diffusional behavior of the penetrant in the polymer matrix is related to the penetrant size and the diffusion sites available.…”

Section: Introductionmentioning

confidence: 99%

The influence of moisture content on the polymer structure of polyvinyl alcohol in dispersion barrier coatings and its effect on the mass transport of oxygen

et al. 2017

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This paper presents a study of the effect of moisture on the gas permeability of polyvinyl alcohol (PVOH) and PVOH-kaolin dispersion barrier coatings. The oxygen permeability was measured at different humidity levels, and the material properties were characterized under the same conditions: polymer crystallinity, kaolin concentration, and kaolin orientation were all evaluated. The experimental results revealed that the water plasticizes the PVOH material of the coatings, and the presence of kaolin filler is unable to affect such behavior significantly. The PVOH crystallinity was affected drastically by the humidity, as water melts polymer crystallites, which is a reversible process under removal of water. The permeability data were analyzed using a thermodynamicbased model able to account for the water effect on both the solubility of the gas and the diffusivity coefficients in the polymer and composite. The results showed good agreement between the model's predictions and the experimental data in terms of the overall permeability of the material.

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NELF model prediction of the infinite dilution gas solubility in glassy polymers

Cited by 74 publications

References 67 publications

Nonequilibrium Lattice Fluid Modeling of Gas Solubility in HAB-6FDA Polyimide and Its Thermally Rearranged Analogues

Nonequilibrium Lattice Fluid Modeling of Gas Solubility in HAB-6FDA Polyimide and Its Thermally Rearranged Analogues

Predictive calculation of hydrogen and helium solubility in glassy and rubbery polymers

The influence of moisture content on the polymer structure of polyvinyl alcohol in dispersion barrier coatings and its effect on the mass transport of oxygen

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