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  • 1
    Electronic Resource
    Electronic Resource
    The “barrer” permeability unit (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1933-1934 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160061108
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  • 2
    Electronic Resource
    Electronic Resource
    Permeation of dimethyl sulfoxide through polyethylene membraness (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 295-305 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Permeability and diffusion coefficients for dimethyl sulfoxide (DMSO) in polyethylene have been measured by the “time-lag” technique and found to be affected by the adsorption of DMSO vapor in the low-pressure side of the apparatus. An analytical method is described for correcting the apparent permeability coefficients for such adsorption effects. “True” permeability coefficients for DMSO in polyethylene, expressed in units of cm3(STP) - cm/(sec-cm2-cmHg), vary from 0.92 X 10-7 at 30°C to 1.7 X 10-7 at 45°C, and their dependence on relative DMSO pressure appears to be small. The energy of activation for the permeation process is 7.1 kcal/mole. The described correction method is also applicable to the permeation of water vapor through polyethylene and poly-(phenylene oxide). The apparent diffusion coefficients could not be corrected by this method. The solubility of DMSO in polyethylene was measured with a Bakr-McBain balance and found to be very small; solubility coefficients are less than 0.8 cm3(STP) DMSO/(cm3 polymer-cmHg). It is concluded that the transport and solution behavior of DMSO in polyethylene is more similar to that of water vapor than to the corresponding behavior of organic vapors.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.160100209
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of pressure on gas permeability coefficients. A new application of free volume theory (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 575-575 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.160100315
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of pressure on gas permeability coefficients. A new application of “free volume” theory (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 201-219 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The present work is a continuation of a general study of the effect of pressure on gas and vapor permeation through nonporous polymeric membranes. Permeability coefficients have been measured for 1,1-difluoroethylene (C2H2F2) and fluoroform (CHF3) in polyethylene at penetrant pressures up to 35 atm and at temperatures between -18 and 70°C. The permeability coefficient P̄ for the 1,1-difluoroethylene - polyethylene system was found to increase with increasing pressure differential Δp across the membrane. Isothermal plots of log ΔP versus Δp are generally linear and can be represented by empirical relations of the form ΔP = P(0)exp{m Δp}, where P(0) and m are constants. The slope m of these isotherms decreases with increasing temperature. Plots of log P̄ versus Δp for the fluoroform - polyethylene system are also linear, but exhibit negative slopes, i.e., P̄ decreases with increasing Δp. An extension of Fujita's “free volume” theory of diffusion in polymers shows that the dependence of P̄ on pressure reflects how the free volume of the polymer is affected by this pressure. An increase in the penetrant pressure may result in two opposing effects: (a) the concentration of the penetrant dissolved in the membrane is increased, thereby increasing the free volume, and (b) the hydrostatic pressure on the membrane is also increased, which causes a decrease in the free volume. If the overall effect is an increase in the free volume of the polymer, then P̄ will also increase, and vice versa.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.160100202
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  • 5
    Electronic Resource
    Electronic Resource
    Transport of heavy organic vapors through silicone rubber (1973)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 11 (1973), S. 663-681 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Permeability, solubility, and diffusion coefficients have been determined for halothane (CF3CHClBr) and methoxyflurane (CHCl2CF2OCH3) in silicone rubber at temperatures from 17 to 60°C and at relative pressures from 0.05 to 0.96. The solubility of both penetrants in silicone rubber is a strong function of penetrant concentration (or relative pressure), and can be represented satisfactorily by the Flory-Huggins relation with single values of the interaction parameter χ. The solubility coefficients decrease with increasing temperature at constant pressure. Mutual diffusion coefficients exhibit maxima when plotted against penetrant concentration; these maxima are attributed to the mass flow of polymer together with dissolved penetrant. Intrinsic diffusion coefficients increase linearly with increasing concentration. The energies of activation for diffusion are low, probably because of the ease of segmental motion about the Si—O linkage. The diffusivity data are examined in terms of Fujita's “free volume” model and of transition-state theory. Permeability coefficients for the two penetrants are large, of the order of 10-6-10-5 cm3(STP)-cm/(sec-cm2-cm Hg), and increase markedly with increasing concentration or decreasing temperature. This behavior is regarded as a consequence of the low energies of activation for diffusion.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1973.180110404
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  • 6
    Electronic Resource
    Electronic Resource
    Solubility of carbon dioxide in cellulose acetate at elevated pressures (1978)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 16 (1978), S. 735-751 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The solubility of carbon dioxide in symmetric (dense) cellulose 2.4-acetate has been measured at temperatures from 0 to 70°C and pressures up to 45 atm. The polymer samples were prepared by slowly drying asymmetric reverse osmosis membranes. The solubility isotherms can be described satisfactorily up to 60°C by the “dual-sorption” model for glassy polymers. The model cannot represent the experimental data above 60°C, possibly because of a second-order transition in the polymer between 60 and 70°C. An analysis of the dual-sorption parameters and of the heats of solution and “hole filling” suggests that the polymer samples contained a relatively large volume of microcavities. Gas solution appears to occur predominantly in microcavities, a large fraction of the penetrant moleculers being immobilized or partially immobilized. The solubilities obtained in this work are compared with similar data computed from time-lag measurements of other investigators, and the validity of the dual-sorption model is examined for the present case.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1978.180160415
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  • 7
    Electronic Resource
    Electronic Resource
    Tests of a “free-volume” model of gas permeation through polymer membranes. I. Pure CO2, CH4, C2H4, and C3H8 in polyethylene (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 467-481 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Permeability coefficients have been measured for CO2, CH4, C2H4, and C3H8 in polyethylene membranes at temperatures of 5, 20, and 35°C and at applied gas pressures of up to 30 atm. The temperature and pressure dependence of the permeability coefficients was represented satisfactorily by an extension of Fujita's free-volume model of diffusion of small molecules in polymers. The results of the present steady-state permeability measurements provide further support for the conclusion reached from previous unsteady-state diffusivity measurements that Fujita's model is applicable to the transport of small molecules, such as CO2, CH4, C2H4, and C3H8, in polyethylene. It was previously thought that this model is applicable only to the transport of larger molecules, such as of organic vapors, in polymers.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210311
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  • 8
    Electronic Resource
    Electronic Resource
    Tests of a free-volume model for the permeation of gas mixtures through polymer membranes. CO2-C2H4, CO2-C3H8, and C2H4-C3H8 mixtures in polyethylene (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 1275-1298 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Steady-state permeability coefficients have been measured for equimolar mixtures of CO2-C2H4, CO2-C3H8, and C2H4-C3H8, as well as for a mixture of 74.9 mol % CO2 and 25.1 mol % C2H4 in polyethylene membranes. The measurements were made at 20, 35, and 50°C and at pressures of up to 28 atm. Each component of the permeating mixtures studied had the effect of increasing the permeability coefficient for the other component. Furthermore, at equal partial pressures and at the same temperature, the component exhibiting the highest solubility in the polymer had the largest effect in increasing the permeability coefficient of the other component. This behavior is in agreement with the predictions of a free-volume model for the permeation of gas mixtures proposed by Fang, Stern, and Frisch. From a quantitative viewpoint, the permeability coefficients for the components of the mixtures agreed, on the average, to better than 25% with the predicted values. The theoretical permeability coefficients can be estimated from the model by using parameters determined with the pure components only.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210802
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  • 9
    Electronic Resource
    Electronic Resource
    The diffusion of CO2, CH4, C2H4, and C3H8 in polyethylene at elevated pressures (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 441-465 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Diffusion and solubility coefficients have been determined for the CO2-, CH4-, C2H4-, and C3H8-polyethylene systems at temperatures of 5, 20, and 35°C and at gas pressures up to 40 atm. Diffusion coefficients were obtained from rates of gas absorption in polyethylene rods under isothermal-isobaric conditions by means of a new diffusivity apparatus. The concentration dependence of the diffusion coefficients was represented satisfactorily by Fujita's free-volume model, modified for semicrystalline polymers, while the solubility of all the penetrants in polyethylene was within the limit of Henry's law. Semiempirical correlations were found for the free-volume parameters in terms of physicochemical properties of the penetrant gases and the penetrant-polymer systems. These correlations, if confirmed, should permit the prediction of diffusion and permeability coefficients of other gases and of gas mixtures in polyethylene as functions of pressure and temperature.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210310
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