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  • Polymer and Materials Science  (187)
  • Physical Chemistry  (13)
  • Wiley-Blackwell  (200)
  • 1970-1974  (191)
  • 1950-1954  (9)
  • 1973  (191)
  • 1950  (9)
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  • Wiley-Blackwell  (200)
Years
  • 1970-1974  (191)
  • 1950-1954  (9)
Year
  • 1
    Electronic Resource
    Electronic Resource
    A cooperative molecular weight distribution test (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 269-282 
    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 development of gel permeation chromatography (GPC) has provided a convenient tool for the rapid determination of molecular weight distribution. The question has arisen as to the suitability of the method for specification purposes. The present work, suggested by the Naval Air Systems Command, represents an attempt to assess the precision of the method through a series of tests carried out by a number of laboratories using identical procedures on the same samples. Ten laboratories agreed to take part. Naval Ordnance Station, Indian Head, worked out standard conditions for operation of the chromatograph, for calibration of the columns, and for analysis of the GPC curves. Two samples of polystyrene were used by the various organizations for calibration of their instruments. Number-average molecular weight, heterogeneity index, and cumulative molecular weight distribution curves were determined on four samples of carboxyl-terminated polybutadiene (CTPB) and two samples of hydroxyl-terminated polybutadiene (HTPB), all unidentified except by letter code. All laboratories used identical directions for setting up CTPB and HTPB calibration curves which were based on curves determined from vapor-pressure osmometer molecular weights and GPC count numbers of fractionated material. Variation among the different laboratories was 0.15 in heterogeneity index, and a maximum of 1200 in molecular weight provided one aberrant set of values was eliminated. The six samples had heterogeneity indices from 1.15 to 1.54, while molecular weight varied from approximately 3000 to 6000. The average coefficient of variation of the molecular weight values was 6.2 ± 0.7%, which is quite acceptable. Variation in heterogeneity index was too great for specification purposes when considered among the different laboratories, but may be sufficiently good when measured by any one laboratory.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070170121
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  • 2
    Electronic Resource
    Electronic Resource
    The electroinitiated polymerization of N-vinylcarbazole with zinc bromide, IIPart I: cf.12.. Kinetics of polymerization (1973)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 169 (1973), S. 177-189 
    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 elektroinitiierte Polymerisation von N-Vinylcarbazol (VCZ) wurde in Aceton bei 25°C mit Zinkbromid als Katalysator unter Verwendung von Platinelektroden eingehend untersucht. Die Polymerisationsgeschwindigkeit erwies sich als direkt abhängig von der Stromstärke, der Zinkbromid-Konzentration und dem anfänglichen Wassergehalt des Solvens.Die Molekulargewichte der entstandenen Polymeren (1000-6000) sind unabhängig von der Stromstärke, der Zinkbromid-Konzentration und dem Umsetzungsgrad des Monomeren zum Polymeren, werden jedoch beeinflußt durch Wasser, die Monomerkonzentration und das Elektrodenmaterial. Die chemische Zusammensetzung der Polymeren ändert sich nicht mit der Stromstärke, der Zinkbromid-Konzentration, dem Umsetzungsgrad und dem Elektrodenmaterial. Sie ändert sich jedoch ein wenig mit dem Wassergehalt des Acetons.
    Notes: The electroinitiated polymerization of N-vinylcarbazole (VCZ) in acetone solvent at 25°C with zinc bromide, as catalyst, and platinum electrodes was investigated in detail. The polymerization rate was found to be directly dependent on current strength, zinc bromide concentration and the initial water content of the solvent.The molecular weights of the formed polymers (1000-6000) are independent of current strength, zinc bromide concentration and degree of conversion of monomer to polymer, but are affected by water, monomer concentration, and by the type of electrodes used. The chemical composition of the polymer is invariant with current strength, zinc bromide concentration, degree of conversion, and electrode material but does vary slightly with the water content of acetone.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1973.021690117
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  • 3
    Electronic Resource
    Electronic Resource
    The photodegradation of poly(1,3-phenylene isophthalamide) films in air (1973)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 11 (1973), S. 683-688 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1973.130111104
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  • 4
    Electronic Resource
    Electronic Resource
    The photodegradation of poly(1,3-phenylene isophthalamide) films under vacuum (1973)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 11 (1973), S. 149-155 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1973.130110301
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  • 5
    Electronic Resource
    Electronic Resource
    The rate of γ-benzyl-L-glutamate NCA polymerizations (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 647-654 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The primary amine initiated homopolymerization of γ-benzyl-L-glutamate NCA in dioxane at 25°C, 35°C, 50°C, and 65°C has been investigated. The reactions were virtually independent of temperature indicating an activation energy of less than 1 kcal/mole. The entropy of activation was estimated to be -65 entropy units at 300°K. The reaction proceeded in two stages. The first stage was zero-order with respect to monomer, whereas the second was first-order with respect to monomer. Both stages were first-order with respect to initiator. These results were interpreted by assuming that the rate constant for propagation was not independent of the degree of polymerization up to the point where a conformational transition to α-helix occurred.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360120316
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  • 6
    Electronic Resource
    Electronic Resource
    Vibrational spectra and dispersion curves of poly-L-proline II chain (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 1377-1385 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using Wilson's GF-matrix method as modified by Higgs for infinite helical polymers, dispersion curves and the frequency distribution function have been calculated for poly-L-proline II chain. Infrared spectrum is obtained and a Urey-Bradley force field, which provides best fit with the observed frequencies, is evaluated. The result are discussed from the viewpoint of the conformational characteristics of forms I and II.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360120613
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  • 7
    Electronic Resource
    Electronic Resource
    Polymerization of methyl methacrylate by catalyzed peroxide decomposition without applied heat (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 2771-2782 
    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 exotherm for the polymerization of methyl methacrylate was monitored by a simple thermal technique to gain useful information about the effect of several factors on the polymerization rate and the degree of completion. All reactions were begun at room temperature (24°C) and no external heating was provided. Initiation was by decomposition of benzoyl peroxide (and mixtures with lauroyl peroxide) catalyzed by the accelerator N,N-dimethyl-p-toluidine. Specific factors examined were peroxide and accelerator levels, sample size, peroxide combinations, and crosslinking agents. The results are discussed in terms of the stoichiometry of the initiator system; the balance of heat generation, heat capacity, and heat loss; and the autoacceleration effect.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070170914
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  • 8
    Electronic Resource
    Electronic Resource
    Atmosphärische Korrosion des Eisens bei periodischer Befeuchtung (1973)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 24 (1973), S. 684-691 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Atmospheric corrosion of iron with periodic moisteningPeriodic moistening has a considerable bearing on the model of the corrosion of iron. The frequency of condensation is much more important than the duration of the existence of a condensed layer. Immediately upon condensation a steep increase of the corrosion rate is found. These periods of condensation thus control the rate and the intensity of the attack. The results of measurements concerning the dependence on time, and of radiochemical experiments (concerning the behaviour of sulphate ions) allow the conclusion that condensation intervenes in the reaction system and affects the availability of sulphate ions at the interphase as well as the function of water. In this context the difference between adsorbed and condensed aqueous layers should be taken into consideration. It is suggested to develop a numerical index allowing the duration of accelerated corrosion to be determined in terms of the frequency of condensations.
    Notes: Periodische Befeuchtungen beeinflussen das Modell der Eisenkorrosion beträchtlich. Dabei ist die Häufigkeit der Kondensationen wesentlich einflußreicher als die Dauer der Existenz einer kondensierten Schicht. Unmittelbar nach der Kondensation ist ein starker Anstieg der Korrosionsgeschwindigkeit festzustellen. Diese Kondensationsperioden bestimmen daher die Geschwindigkeit und die Stärke des Angriffs. Auf der Grundlage der Messungen über die Zeitabhängigkeit und auf der Basis von radiochemischen Untersuchungen (über das Verhalten der Sulfationen) kann man schließen, daß die Kondensation in das Reaktionssystem eingreift, und zwar hinsichtlich der Verfügbarkeit der Sulfationen an der Grenzfläche und hinsichtlich der Funktion des Wassers. Dabei ist auch der Unterschied zwischen adsorbierten und kondensierten Wasserschichten zu berücksichtigen. Es wird vorgeschlagen, eine Indexzahl zu entwickeln, welche die Bestimmung der Dauer der beschleunigten Korrosion in Abhängigkeit von der Häufigkeit der Kondensation ermöglicht.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19730240803
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  • 9
    Electronic Resource
    Electronic Resource
    Copolymerization of γ-benzyl-D,L-glutamate NCA (1973)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 169 (1973), S. 191-197 
    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 Copolymerisation von γ-Benzyl-D- und L-glutamat wurde in Dioxan bei 25, 35, 50 und 65°C untersucht. Die Bruttogeschwindigkeitskonstanten wurden auffällig wenig von der Temperatur beeinflußt, was auf eine Aktivierungsenergie von weniger als 1 kcal/mol hinweist. Die Umsatz/Zeit-Kurven zeigen zwei unterschiedliche Prozesse an: eine anfängliche, von der Monomerzusammensetzung unabhängige Reaktion des wachsenden Polymeren in der Konformation eines statistischen Knäuels mit dem Monomeren und eine zweite, stereoselektiv verlaufende Wachstumsreaktion des Polymeren in der Konformation einer α-Helix. Die Stereoselektivität der Polymerisation rührt vermutlich von einer spezifischen Adsorption des Monomeren an einer Stelle zwischen dem helixartigen und etwa dem drittletzten Grundbaustein des nicht-helixartigen Teils jedes wachsenden Polymermoleküls her.
    Notes: The copolymerization of γ-benzyl D- and L-glutamates has been investigated in dioxane at 25,35,50, and 65°C using hexylamine as initiator. Temperature changes had remarkably little effect on the overall rate constants indicating an activation energy of less than 1 kcal/mol. The rate curves indicated two stages in the polymerization process: an initial reaction of random coil with monomer which was independent of monomer composition and a final reaction between α-helical polymer and monomer which occurred stereoselectively. The conclusion was reached that the origin of the stereoselectivity was a specific adsorption of monomer at a site between the α-helical polymer and the “random” three or so end units of each polymer molecule.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1973.021690118
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  • 10
    Electronic Resource
    Electronic Resource
    Heats of thermally induced helix-coil transitions of DNA in aqueous solution (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 1829-1836 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermal denaturation of calf thymus DNA at both alkaline and neutral pH values was studied by differential scanning calorimetry. It was shown that the dependence of the enthalpy of transition on pH and salt concentration could be accounted for on the basis of a heat capacity change of +40 cal deg-1(base pair)-1. In the pH range between 10.3 and 11.3, a release of 0.6 proton per base pair was calculated from the pH dependence of the melting temperature. The heat effect associated with the release of this proton was calculated to be 5 kcal mole-1.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360120810
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