Predicting gas solubility in semi-crystalline polymer solvent systems by consistent coupling of Sanchez-Lacombe EOS with a continuum mechanics approach

Fischlschweiger, Michael; Danzer, Andreas; Enders, Sabine

doi:10.1016/j.fluid.2019.112379

Cited by 11 publications

(26 citation statements)

References 71 publications

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“…Some authors believe that the constraint pressure is of a mechanical origin, either due to potential residual stresses in the polymer following crystallization or due to the formation of cavities needed to accommodate the solute particles in the amorphous domains. 26 We take another perspective in our current work, namely that the constraint pressure originates from the elastic forces exerted by the tie-chains and tie-entanglements 27 on the interlamellar amorphous domains and from the localization in space of the polymer segments. This hypothesis stems from the observation that in cross-linked polymer networks (such as rubbers and gels) the bulk solubility is lower than the one measured for non-cross-linked polymers.…”

Section: Modeling Sorption In Semicrystalline Polymersmentioning

confidence: 99%

Influence of Tie-Molecules and Microstructure on the Fluid Solubility in Semicrystalline Polymers

et al. 2022

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Predicting the absorption of gases and liquids in semicrystalline polymers is of critical importance for numerous applications; the mechanical and transport properties of these materials are highly dependent on the amount of solutes dissolved in their bulk. For most semicrystalline polymers which are in contact with an external fluid, the observed uptake of the solute is found to be lower than that predicted by treating the amorphous domains of the polymer as subcooled polymer melts at the same thermodynamic state. This observation has recently led to the hypothesis that the amorphous domains effectively behave as polymer liquids subject to an additional “constraint pressure” which reduces the equilibrium solubility in the domains. We present a new statistical mechanical model of semicrystalline polymers. The constraint pressure emerges naturally from our treatment, as a property of the interlamellar amorphous domains caused by the stretching and localization in space of the tie-molecules (polymer chains linking different lamellae). By assuming that the interlamellar domains exchange monomers reversibly with the lamellae, the model allows one to simultaneously predict the increase of constraint pressure at low temperatures and the variation of the lamellar thickness as a function of temperaturea phenomenon known as premelting. The sorption isotherms of a range of fluids in different polyethylene and polypropylene samples are determined experimentally and the data is compared with calculations of the new model using the SAFT-VR Mie EoS. In order to accurately predict the absorption close to the vapor pressure of the penetrant, we find that it is essential to include the “free”, unconstrained amorphous domains in the description, resulting in a multiscale model with two adjustable parameters (the fractions of tie-molecules and free amorphous domains) that characterize the morphology of a given semicrystalline polymer sample. The trends observed for the adjusted parameters qualitatively match other estimates reported in the literature.

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Section: Modeling Sorption In Semicrystalline Polymersmentioning

confidence: 99%

Influence of Tie-Molecules and Microstructure on the Fluid Solubility in Semicrystalline Polymers

et al. 2022

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“…Thus, sorption in the amorphous phase is calculated with a non-equilibrium model and an adjusted value of the density. Minelli and De Angelis [46] and more recently, Fischlschweiger et al [47] also considered the rubbery amorphous phase to be constrained by the presence of crystallites, but instead of invoking a non-equilibrium behavior, considered that the amorphous phase is at equilibrium with a much higher pressure value than the one imposed by the gas phase only, due to the stress exerted by the crystals. The total pressure acting on the amorphous phase is the sum of the actual gas pressure and the "constraining pressure" imposed by crystals.…”

Section: Thermodynamic Model For Solubilitymentioning

confidence: 99%

Towards a systematic determination of multicomponent gas separation with membranes: the case of CO2/CH4 in cellulose acetates

Ricci

Maio

Esposti

et al. 2021

Journal of Membrane Science

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“…11,12 Consequently, this results in a heterogeneous intrinsic pressure distribution within the semicrystalline polymer. 13 The crystalline regions, with folded chains and ordered lamella, present barriers to gas solubility. They tend to influence the unrestrained expansion of the amorphous phase induced by gas sorption.…”

Section: Introductionmentioning

confidence: 99%

“…Based on this framework the induced eigen pressure by dissolving nbutane and i-butane in low-density polyethylene at low degrees of crystallinity was calculated, and the gas solubility could be predicted in the semicrystalline state for low-temperature isotherms. 13 In this work, we will set up on ref 13 and further develop this method with a new multiscale approach that incorporates the geometric shape of crystals and the temperature-dependent mechanical properties of the amorphous phase of the pure polymer. Based on this the gas solubility in semicrystalline polymers showing higher and more complex semicrystalline morphologies should be predicted.…”

Section: Introductionmentioning

confidence: 99%

Gas Solubility Modeling of Ethylene in Semicrystalline Polyethylenes with Different Macromolecular Architectures Based on a Thermomechanics Approach

Zimmermann,

Enders,

Fischlschweiger

2023

J. Chem. Eng. Data

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The solubility of gases in semicrystalline polymers is a significant property with numerous applications, such as gasphase polymerization. Although thermodynamic modeling has successfully determined gas solubility in glassy polymers or polymer melts without crystallites, predicting gas solubility in polymers with a semicrystalline morphology remains challenging. This study presents a novel multiscale modeling approach based on thermomechanics to predict gas solubility in semicrystalline polymers across different temperatures, pressures, and various grades of polyethylene. The thermomechanical framework incorporates the SL-EOS and continuum mechanics, utilizing a mechanical homogenization method to consider the semicrystalline morphology and obtain local mechanical material information. Additionally, the temperature dependence of the degree of crystallinity of polyethylene is considered. By employing this approach, the solubility of ethylene in different polyethylene grades in the semicrystalline state can be accurately predicted, demonstrating good agreement with experimental data with a relative error below 3%.

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Predicting gas solubility in semi-crystalline polymer solvent systems by consistent coupling of Sanchez-Lacombe EOS with a continuum mechanics approach

Cited by 11 publications

References 71 publications

Influence of Tie-Molecules and Microstructure on the Fluid Solubility in Semicrystalline Polymers

Influence of Tie-Molecules and Microstructure on the Fluid Solubility in Semicrystalline Polymers

Towards a systematic determination of multicomponent gas separation with membranes: the case of CO2/CH4 in cellulose acetates

Gas Solubility Modeling of Ethylene in Semicrystalline Polyethylenes with Different Macromolecular Architectures Based on a Thermomechanics Approach

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