Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A model of physical adsorption of gasesThis paper was part of a Ph.D. thesis (Frankfurt am Main, December 1977) of one of the authors (H.G.B.). (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 24 (1979), S. 1479-1495 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Using the Gibbs description of surfaces, a sorption model is developed which describes sorption isotherms for such systems as water in polymers. Moreover, the Freundlich isotherm for monolayer sorption is obtained. The physical interpretation of the constants of the model and the boundary conditions required for application to sorption isotherms are discussed. On basis of the Freundlich isotherm, a multilayer model is proposed to describe the water sorption in polymers. Experimental results within the whole range of relative humidity are found to be in excellent agreement with the multilayer model. Disagreement between model isotherm and experimental data of some polymers at relative humidities above 90% might be due to capillary phenomena not considered in the present model description.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070240609
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The thermodynamic state of water in cellulose acetate membranes (1980)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 20 (1980), S. 305-309 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Using experimental sorption data and corresponding experimental results from calorimetric investigations, the state of water in cellulose acetate (CA) membranes is discussed by applying a theoretical treatment of sorption reported previously (1-3). The sorption of water can be attributed to a gain in surface energy at the polymer/vapor interface. Using differential thermodynamic potentials of sorbed water together with experimentally determined heat capacities of sorbed water, the thermodynamic potentials G, H, and S of sorbed water are estimated for the temperature interval -40 to + 40°C. At constant temperature, each thermodynamic potential depends on the water content. The resulting distribution function of G indicates that the sorbed water exists in different states. Comparing the Gibbs free energy of sorbed water with that of ice or liquid water at the same temperature leads to the conclusion that none of the sorbed water freezes to ice within the temperature interval used. Based on the Gibbs free energy of water in electrolyte solutions and the distribution function of G for sorbed water, partition coefficients of salts within CA membranes may be estimated. The results are in good agreement with experimentally determined partition coefficients which are available from the literature. As the partition coefficient of a salt is directly related to the salt rejection of the membrane, this provides a method of estimating the desalination performance of a membrane from its water sorption isotherm.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760200415
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Thermodynamic and mechanistic characterization of water sorption in homogeneous and asymmetric cellulose acetate membranes (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 20 (1976), S. 789-797 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The water sorption isotherms for homogeneous and asymmetric cellulose acetate membranes have been measured at different temperatures. Subtle differences between the water sorption isotherms for asymmetric and homogeneous membranes have been interpreted by suggesting that capillary condensation contributes significantly to sorption in asymmetric membranes at high activities and also to an intriguing excess sorption observed in homogeneous membranes at intermediate activities. This model has been supported by the experimentally determined values of the enthalpy and entropy changes associated with sorption.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1976.070200319
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Characterization of water structure in cellulose acetate membranes by calorimetric measurements (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 473-484 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The heat capacities of homogeneous and asymmetric cellulose acetate membranes have been measured at different water contents within the temperature range of -40 to +20°C. The experimental heat capacity-temperature curves were verified by DTA measurements within a temperature range of -120 to +20°C. The results for the partial heat capacity of water within the membranes as well as for the heat of fusion were interpreted by assuming two different states of water - unfreezing bound water due to a sorption process and unbound water due to capillary phenomena, which freezes with a freezing point depression and a reduced heat of fusion.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070230217
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Characterization of transport across cellulose acetate membranes in the presence of strong solute-membrane interactions (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 25 (1980), S. 323-347 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Certain organic solutes, including phenol, undergo anomalous enrichment when hyperfiltered through cellulose acetate membranes: the solute concentration is higher in the permeate than in the feed solution. A number of existing theoretical approaches describing hyperfiltration phenomena are presented and their merits and limitations upon application to the transport of phenol discussed. A new two-parameter transport relationship is derived based on an extension of the solution-diffusion model. The enrichment, or negative solute rejection by the membrane, is predicted to occur whenever the pressure-induced solute permeation velocity exceeds that of water. By acknowledging and incorporating the effect of pressure on the chemical potential of the solute, the present extended solution-diffusion model relationship successfully describes hyperfiltration data of phenol in homogeneous and asymmetric cellulose acetate membranes provided the contribution of convective flow to the overall solute transport is insignificant. In addition to the transport parameters of the extended solution-diffusion model, the transport parameters of the phenomenological, Kedem-Spiegler, and combined viscous flow-frictional relationship are evaluated from hyperfiltration data obtained with 0.05 and 0.1 wt % phenol feed solutions and homogeneous cellulose acetate membranes of different acetyl content.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1980.070250301
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...