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  • Articles  (6)
  • Polymer and Materials Science  (6)
  • Physics  (1)
  • 1965-1969  (6)
  • 1
    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: Für die Molekulargewichtsbestimmung von Nichtelektrolyten in der Ultrazentrifuge werden Gleichungen für den Virialkoeffizienten B und den Mittelwert M̄z+1 für zwei Kondensationspolymere abgeleitet. Das Verhältnis M̄z+1/M̄z wird 4/3 für A—B- und 10/3 für A—R—B2-Polykondensate. Für die apparenten Mittelwerte M̄z und M̄w ergibt sich für die Virialkoeffizienten die Beziehung Bz/Bw = 2 M̄w/M̄z.Verzweigte niedermolekulare Polymere, die aus „dentcorn“-Stärke isoliert waren, ergaben M̄z/M̄w = 2,9, während sich aus Bz/Bw der Wert 3,9 errechnet. Für die Komponenten am Zellenboden war M̄z,b/M̄w,b = 1,6, während dort aus Bz/Bw der Wert 2,0 folgt. Damit erklärt die theoretische Gleichung, warum Bz kleiner sein kann als Bw.
    Notes: Equations were developed for the concentration coefficient of a nonelectrolyte in ultracentrifugal molecular weight determinations and for the expected value of M̄Z+1 for both A—B- and A—R—B2-condensation polymers. The value of M̄Z+1/M̄Z is 4/3 for A—B-polymers and 10/3 for A—R—B2-polymers. The equations show that the concentration coefficient from the apparent Z-average molecular weight (Bz) divided by that from the apparent weight-average molecular weight (Bw) should be Bz/Bw = 2 (M̄w/M̄z). Data were obtained on a low-molecular-weight branched polymer isolated from dent corn starch. The values of M̄z/M̄w obtained from the extrapolated molecular weights for the entire sample and for the components at cell bottom (b) were M̄z/M̄w = 2.9 and M̄z,b/M̄w,b = 1.6, whereas the respective values of the ratio from Bz/Bw were M̄z/M̄w = 3.9 and M̄z,b/M̄w,b = 2.0. Hence, the theoretical equation Bz/Bw = 2 (M̄w/M̄z) explains why the value of Bz can be less than the value of Bw for heterogeneous polymers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1795-1799 
    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
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    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: Kinetic equations for the decomposition of S-hydroxymethyl cellulose xanthate in the presence of acid and formaldehyde are derived. The assumed mechanism involves an equilibrium between the S-hydroxymethyl cellulose xanthate and cellulose xanthic acid and xanthate ion. Decomposition appears to proceed via interaction between the cellulose xanthate ion and hydrogen ion which form an activated complex that subsequently decomposes to cellulose and carbon disulfide. The equations derived show the proper dependence on acid and formaldehyde concentrations. An estimate of the equilibrium constant between cellulose xanthate and S-hydroxymethyl cellulose xanthate is calculated from the rate constants.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 2511-2525 
    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 comparative study was made of two methods of mounting yarns in the Weatherometer. In the first, in which test materials are wound continuously around separated halves of wooden hubs, the yarns tend to bunch. In the second, the sample is constrained from bunching but is free to relax or to shrink. Use of the second method of mounting significantly shortens exposure time and greatly improves the repeatability of tensile and elongation tests performed on exposed yarns.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Nylon 66 films exhibiting form I melting behavior show the γ mechanical relaxation at -140°C. Samples which have form II melting behavior do not show this relaxation. The γ relaxation disappears when material having form I behavior is converted to material having form II behavior by annealing or by cold drawing. The form I and form II types of melting behavior are also found in poly(ethylene terephthalate); the interconversions and thermal behavior of the forms are analogous to the nylon 66 case. In poly(ethylene terephthalate), the β relaxation at -40 to -60°C is present only when form I melting behavior is found. Conversion to form II melting behavior by annealing or drawing (80°C) again causes the relaxation to disappear. No β relaxation was found in amorphous polymer. The γ dispersion in nylon 66 and the β dispersion in poly(ethylene terephthalate) can therefore be associated with the crystalline structure responsible for form I melting behavior. Form I melting behavior has been associated with foldedchain crystals based on previous work. It is therefore postulated that the γ dispersion in nylon 66 and the β dispersion in poly(ethylene terephthalate) are associated with motions in the chain folds. This assignment is not inconsistent with the change in the γ dispersion of nylon 66 with the number of backbone CH2 units, since these will affect the fold structure.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 627-638 
    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 mobility of polymer chain segments is shown to play a major role in the diffusion of dyes in nylon 66. The rate of dye diffusion has been related to the time-dependent mechanical properties, such as creep and stress relaxation, which are controlled by the mobility of the chain segments. The theoretical relations derived by Fujita et al. relating the diffusion of small molecules in amorphous polymers to other properties are shown to be applicable for the dyeing of semicrystalline nylon. Data showing the effects of surface area, temperature, and the amount of dye absorbed at saturation on the dyeing rate are presented and discussed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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