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  • 1
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 1 (1990), S. 19-25 
    ISSN: 1042-7147
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: When a water-swollen polyelectrolyte gel is interposed between a pair of electrodes and DC current is applied, the gel undergoes electro-chemomechanical contraction and concomitant water exudation both in water and in the air. In order to clarify the mechanism of the phenomenon, contractile experiments were carried out under various conditions and led to the conclusion that the contraction is essentially associated with electrically driven movement of hydrated micro- and macroions in the gel (electrokinetic process).
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1306-1311 
    ISSN: 0032-3888
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: It is shown that ion-dipole interactions induce considerable miscibility enhancement in blends of styrene ionomers with poly(alkylene oxides). Dynamic mechanical studies, in conjunction with transparency and brittleness of the samples, are used to evaluate miscibility. The effect is clearly thermodynamics in that phase separation can be induced in miscible samples by raising the temperature, with miscibility reestablished ons cooling. The miscibility enhancement in these systems is compared with that resulting from hydrogen bonding. In addition to the styrene/alkylene oxide system, ion-dipole interactions are found to be effective in enhancing the miscibility of many ionic polymer/polar polymer pairs. The ionomers used in this study were styrene lithium methacrylate and ethyl acrylate lithium acrylate copolymers, while polyethers, polysulfides, polyesters, polyimines, and substituted polyethylenses served as polar polymers.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 55 (1995), S. 343-349 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The shifts in membrane potential, caused by the injection of some amino acids into a permeation cell, were measured using immoblized γ-globulin membranes. The shifts in membrane potential were observed to be positive or negative when the isoelectric point of each amino acid injected into the cell was less or higher than 6.0. The potential response caused by the injection of each amino acid shows an individual and characteristic curve depending on the amino acid, and the difference in potential curves between D-aspartic acid and L-aspartic acid is significantly observed in the immobilized γ-globulin membranes. The t3/4 value was found to increase in the following order: lysine = glutamic acid 〈arginine 〈 D-aspartic acid = asparagine 〈 L-aspartic acid 〈 histidine 〈 alanine, where t3/4 indicates the time at which 75% of the shifts in membrane potential has been observed. The modified membrane potential theory provides satisfactory explanations for the membrane potential obtained experimentally before and after the injection of L-alanine, and the theoretical shifts can explain the experimental shifts in membrane potential due to the injection of L-alanine into the cell. © 1995 John Wiley & Sons, Inc.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 27 (1989), S. 1043-1056 
    ISSN: 0887-6266
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The structure of soluble polyelectrolyte complexes composed of heparin (Hep) and partially aminoacetalized poly(vinyl alcohol) (PVAA) in aqueous solution was investigated by light scattering. The pH was fixed at 3.2 while the ionic strength and mixing ratio were varied. At high ionic strength (0.5), polyelectrolyte complexes were not formed owing to the screening effect of simple salts on polyion charges. At low ionic strength (0.005), polyelectrolyte complexes formed were stable and dispersed when either the polycation or the polyanion was in great excess, whereas the complexes became unstable and coagulated when the concentrations of polycation and polyanion approached each other. At intermediate ionic strength (0.1), when PVAA was in excess, complex formation was similar to that at low ionic strength (0.005); but with an excess of Hep, polyelectrolyte complexes with similar structure (i.e., roughly spherical with average diameters about 2,700 Å) were formed over a wide range of mixing ratio. This observation is of interest in connection with the physiological activity of Hep in vivo.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 25 (1987), S. 1407-1418 
    ISSN: 0887-6266
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The effect of counterions on the solution properties of two types of ionomers, one based on sulfonated polystyrene and the other based on styrene-methacrylic acid copolymer, was studied by viscosity and light scattering measurements. It was found that the order of counterion binding of ionomers in a polar solvent and the order of aggregation of ionomers in a low-polarity solvent were the same for the same ionomer system. However, the order for the sulfonated ionomer was Li 〈 Na 〈 K 〈 Cs, whereas that for the carboxylated ionomer was the opposite. This can be explained by a difference in desolvation during anion-cation interaction and by considering site-binding in a polar solvent and the association of ion pairs in a low-polarity solvent. These findings for ionomer systems are parallel to the association behavior of small ions in water, cation affinity in crosslinked resins, and counterion binding of polyelectrolytes in water.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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