Sorption and diffusion of toluene in isotropic and oriented linear polyethylene

Ng, Howard C.; Leung, W. P.; Choy, C. L.

doi:10.1002/pol.1985.180230510

Cited by 22 publications

(7 citation statements)

References 24 publications

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“…That is, because dissolution of gas in semicrystalline polymer takes place in the amorphous part, and not in the crystalline part, the plasticizing factor may be related with the amorphous fraction of polymer. 35 Considering the crystallinities of LDPE (0.43 ) and PP (0.6 ) , values estimated from density data, the difference in the a values can be understood. However the reasons for the exceptionally high value of a for the Ne and H2 group in LDPE are not clear.…”

Section: Pressure Dependence Of Permeability For Var-mentioning

confidence: 99%

The effect of pressure on gas permeation through semicrystalline polymers above the glass transition temperature

Naito¹,

Mizoguchi²,

Terada³

et al. 1991

J Polym Sci B Polym Phys

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A method is proposed to analyze the effect of pressure on permeation of gases through semicrystalline polymers above the glass transition temperature. The method utilizes similarities in molecular diameters of the gases and differences in their solubilities. Two polymers, polyethylene and polypropylene, and a series of gases are chosen for an application of the method, and the effect of pressure on the permeabilities for 10 gases is measured in the pressure range 1–130 atm at 25°C. For polymers, the logarithm of the permeability coefficient is linear in the pressure for each gas, with negative slope for slightly soluble gases (He, Ne, H2, N2, O2, and Ar) and positive slope for highly soluble gases (CH4, Kr, CO2, and N2O). Analyzing these slopes by the method proposed permits contributions of hydrostatic pressure and concentration to the pressure dependence of permeation to be evaluated. On the basis of the results, the mechanism of gas permeation in rubbery films under high pressures is discussed.

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Section: Pressure Dependence Of Permeability For Var-mentioning

confidence: 99%

The effect of pressure on gas permeation through semicrystalline polymers above the glass transition temperature

Naito¹,

Mizoguchi²,

Terada³

et al. 1991

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

show abstract

“…A complication that arises in this method is that diffusivities of guest molecules in a polymer membrane are sensitive to the level of dilation and plasticization that the polymer is experiencing. [18][19][20] This has been addressed by the introduction of a "cohort diffusion" concept, in which all molecules exhibit essentially a composition-averaged diffusivity throughout the membrane. 21…”

Section: Resultsmentioning

confidence: 99%

Data-driven predictions of complex mixture permeation in polymer membranes

Lee

Chen

Nistane

et al. 2023

Preprint

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Membrane-based organic solvent separations are rapidly emerging as a promising class of technologies for enhancing the energy efficiency of existing separation and purification systems. Polymeric membranes have shown promise in the fractionation or splitting of complex mixtures of organic molecules such as crude oil. Determining the separation performance of a polymer membrane when challenged with a complex mixture has thus far occurred in an ad hoc manner, and methods to predict the performance based on mixture composition and polymer chemistry are unavailable thus far. Here, we combine physics-informed machine learning algorithms and mass transport simulations to create an integrated predictive model for the separation of complex mixtures containing up to 400 components via any arbitrary linear polymer membrane. We experimentally demonstrate the effectiveness of the model by predicting the separation of two crude oils within 6-7 % of the measurements. Integration of ML predictors of key sorption and transport properties of molecules with transport simulators constitutes a radical departure from traditional approaches and will open new avenues for the rapid screening of polymer membranes prior to physical experimentation for the separation of complex liquid mixtures.

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“…The penetrant, n -hexane, and amount of sorption increase the free volume in semicrystalline polyethylene during sorption. − Molecular packing of amorphous phase for the high crystalline PE78 is expected to be tight (i.e., less free volume) at this stage, which hinders the penetration of vapor and is evidenced with a shallow slope. As vapor continuously sorbs to a site for sorption, the sorbed vapor may play a role as a plasticizer and increase the free volume so that the amount of sorption increases as indicated with a steep slope.…”

Section: Discussionmentioning

confidence: 99%

Correlation between Structure and Vapor Sorption in Semicrystalline Linear Polyethylene: One Dimensional Nano-Swelling Measured Using in Situ Vapor Sorption Small Angle Neutron Scattering (iVSANS)

Kim

Glinka

2009

Macromolecules

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Changes in the nanoscale structure of semicrystalline polyethylene (PE) resulting from the sorption/ diffusion of hexane-d 14 vapor have been observed and quantified by in situ vapor sorption small-angle neutron scattering (iVSANS). We find a linear correlation between vapor sorption/diffusion and nanoexpansion of the amorphous phase within the lamellae confined in the spherulite domains. The expansion depends on the degree of crystallinity and spherulite perfection. We measured the structure-based sorption kinetics and isotherms of samples with two different crystalline volume fractions (φ Vc ). The low crystalline polyethylene shows a larger expansion in the long period, L, than the high crystalline polyethylene. Low crystalline PE shows a Fickian-like diffusion profile with sorption time while the high crystalline PE (φ Vc ) 78%) shows a S-shape diffusion profile (non-Fickian) at P/P°) 0.95. The diffusion coefficient increases with relative vapor pressure (P/P°) in both materials. The apparent diffusion coefficient in the low crystalline polymer is approximately a factor of 2 higher than that of the more crystalline polymer. On the other hand, effective diffusion coefficients, D eff 's, normalized with the amorphous volume fractions at each vapor activity are identical regardless of crystallinity. This indicates that amorphous volume fraction is the predominant factor that controls transport properties, at least for small diffusing molecules. Furthermore, the one-dimensional expansion is reversible during cyclic sorption and desorption processes, suggesting that the crystals were not destroyed unlike the inference of a previous study. 1

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Sorption and diffusion of toluene in isotropic and oriented linear polyethylene

Cited by 22 publications

References 24 publications

The effect of pressure on gas permeation through semicrystalline polymers above the glass transition temperature

The effect of pressure on gas permeation through semicrystalline polymers above the glass transition temperature

Data-driven predictions of complex mixture permeation in polymer membranes

Correlation between Structure and Vapor Sorption in Semicrystalline Linear Polyethylene: One Dimensional Nano-Swelling Measured Using in Situ Vapor Sorption Small Angle Neutron Scattering (iVSANS)

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