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  • Chemistry  (8)
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  • 1
    Electronic Resource
    Electronic Resource
    Role of pH in charging of glycogen (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 891-896 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Glycogen acquires a negative charge in both alkaline and acidic solutions and can move in an electrical field, its mobility being related to the degree of alkalinity or acidity. There is a slight increase in relative viscosity at both ends of the pH spectrum. These effects and the changes in nuclear magnetic resonance as a function of pH are interpreted.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090803
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  • 2
    Electronic Resource
    Electronic Resource
    Gel-water relationships in hydrophilic polymers: Thermodynamics of sorption of water vapor (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 2023-2032 
    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: A thermodynamic study was conducted of water vapor adsorption on four hydrophilic polymers (agar, carboxymethyl cellulose, gelatin, and maize starch) at 12 and 25°C. Monolayer coverage amounted, after correction for crystallinity, respectively, to 0.93, 1.46, 0.51, and 0.77 mol water/mol monomer. Evidence is adduced from the Bradley equation and thermodynamic data to indicate that at least during coverage with the second layer of water, the energy of adsorption is greater than that due to condensation alone. Differences in the amount of sorption and in the trend of values of ΔS̄° and ΔH̄° with the amount of sorbed water are related with differences in the strength of intermolecular association as affected by steric hindrances.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120904
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  • 3
    Electronic Resource
    Electronic Resource
    Gel-water relationships: Dielectric dispersion (1968)
    New York : Wiley-Blackwell
    Biopolymers 6 (1968), S. 1453-1459 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: At low frequencies, the dielectric constant of gels of agar, carboxymethyl cellulose, gelatin, mid maize starch is much higher than that of water. It decreases continuously as the frequency increases, tending to level off at about 108 cps. The dielectric constant is lower the higher the concentration of polymer; it increases in the order: carboxymethyl cellulose, agar, starch, and gelatin. Results are most reasonably explained by assuming a more solid structure of water the lower the dielectric constant.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1968.360061008
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  • 4
    Electronic Resource
    Electronic Resource
    Role of hydrogen ion concentration in retrogradation of starch sols (1962)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 6 (1962), S. 571-574 
    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: Cornstarch sols were prepared with pH adjusted to various values both before and after gelatinization. Retrogradation was ascertained by measurement of crystallinity (x-ray), enzymatic digestibility, and cold water solubility. When the starch was gelatinized after pH adjustment, maximum retrogradation was at a pH value of about 5, with diminishing retrogradation at higher and lower values. When the starch was gelatinized before pH adjustment, maximal retrogradation occurred at pH values 1-2, with diminishing retrogradation at higher values. After an initial period of rapid retrogradation, retrogradation at all pH values studied follows first-order kinetics. The data are explained in terms of molecular size, role of pH in hydrogen bond rupture, the weakly acidic character of starch, and changes in the configurational entropy of starch molecules.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1962.070062312
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  • 5
    Electronic Resource
    Electronic Resource
    Gel/water relationships in hydrophilic polymers: Nuclear magnetic resonanceThis research was supported by the National Science Foundation (Grant GB 4732). (1968)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 116 (1968), S. 140-145 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die NMR-Spektren der Gele von Agar, Carboxymethylcellulose, Gelatine und Stärke wurden gemessen und analysiert. Die Linienbreite der Protonenresonanz der Hydroxylgruppe nimmt mit der Konzentration des Polymeren zu, im selben Maße nimmt die Signalstärke ab. Außerdem ist eine kleine paramagnetische Verschiebung zu beobachten. Die Änderungen der Signalflächen werden als eine Änderung der relativen Anteile an „festem“, „gebundenem“ und „freiem“ Wasser interpretiert; in Gelen von Gelatine und Stärke wurde kein „festes“ Wasser gefunden. Der Anteil an freiem Wasser nimmt in allen Gelen kontinuierlich mit zunehmender Polymerenkonzentration ab. Die sehr starke Verbreiterung der OH-Resonanz schon bei niederen Agarkonzentrationen wird durch einen wasserordnenden Einfluß der D-Galactopyranoseeinheiten erklärt.
    Notes: The spectra of nuclear magnetic resonance were recorded and analyzed for different concentrations of gels of agar, carboxymethyl cellulose, gelatin, and starch. The line width of the signal of the hydroxyl proton broadens with increasing concentration of polymer, and the signal height continually decreases. A small paramagnetic shift also occurs. Changes in signal areas are interpreted in terms of “solid”, “bound”, and “free” water, with no “solid” water found in gels of gelatin and starch. Free water decreases continuously with increasing concentration in all gels. The very great line-broadening for low concentrations of agar gels is explained by the water-organizing effect of the D-galactopyranose moiety.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1968.021160114
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  • 6
    Electronic Resource
    Electronic Resource
    A low angle spacing in starch (1962)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 56 (1962), S. S10 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1962.1205616330
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  • 7
    Electronic Resource
    Electronic Resource
    Pectic substances-water. I. Structural changes in the polygalacturonide chains during water adsorption (1956)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 22 (1956), S. 303-314 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An apparatus suitable for studying adsorption of water vapor both volumetrically and gravimetrically is described. Water vapor isotherms of highly esterified pectin, sodium pectate and pectic acid were determined. Equatorial and meridional spacings of the x-ray diffraction patterns were measured as a function of equilibrium water content in these materials. The interchain separations, as measured by the changes in the equatorial spacings of x-ray reflections, follow the shape of the adsorption isotherms. In esterified pectin and sodium pectate, the fiber repeat period increases until 5 molecules of water content per 3 galacturonide residues are adsorbed, thereafter remaining constant. The fiber period of pectic acid is constant throughout water adsorption.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1956.1202210112
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  • 8
    Electronic Resource
    Electronic Resource
    Crystallization in starch: The role of ions in the lyotropic seriesThis investigation was supported by grant EF-155 from the U.S. Public Health Service. (1963)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 1 (1963), S. 3547-3559 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The crystallization (retrogradation) of starch from solution has been investigated as a function of electrolyte composition and concentration. The anion effects follow a lyotropic series which causes retrogradation in the approximate descending order: CNS-, (PO4≡, CO3=), I-, NO3-, Br-, Cl-, C2H3O2-, F-, SO4=. Cations also tend to follow the lyotropic series of Ba++, Sr++, Ca++, K+, Na+, Li+. Increasing concentrations of most salts (except for NaF and MgSO4) result in decreased precipitation of starch. The descending order of ions in the lyotropic series is best explained in terms of the decreasing polarity and decreasing relative intensity of electric charge, due either to increasing ion symmetry or to increasing area of charge distribution as a result of resonance among several configurations. It is suggested that the polar, higher charge intensity in ions at the upper end of the series brings about charging of the starch molecule, which leads to solubilization because of (1) the repulsion of the similarly charged molecules and (2) the aggregation of a water mantle about each molecule.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1963.100011203
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