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  • 1965-1969  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Colloid-chemical properties of ω-phenylalkyltrimethylammonium bromides in aqueous solutions (1969)
    Springer
    Colloid & polymer science 229 (1969), S. 159-166 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Surface tension, electrical conductivity, light scattering and nuclear magnetic resonance measurements were carried out in aqueous solutions of a series ofω-phenylalkyltrimethylammonium bromides. The conclusion is summarized as follows. 1) The pentyl and higher homologs form micelles in aqueous solutions, provided the concentration is larger than a definite value (CMC). As expected, CMC decreases and association number of a micelle increases with an increase in the alkyl-chain length. 2) The butyl derivative does not form large aggregates that are qualified to be called “micelles”. No distinct CMC is observed. 3) In a micellar solution, surfactant molecules are rapidly exchanged between micelles and bulk water phase. 4) Critical micelle concentration is affected by the introduction of a phenyl group at the end of an alkyl chain in such a manner as if 2.7 methylene groups were introduced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01552711
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Sintering of aluminium nitride: Particle size dependence of sintering kinetics (1969)
    Springer
    Journal of materials science 4 (1969), S. 1045-1050 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effect of particle size (0.78 ∼ 4.4 μm) on the sintering kinetics of AIN powder was investigated in the temperature range from 1600 to 2000° C and the results were analysed on the basis of vacancy diffusion models. The mechanisms of sintering are discussed. Fractional shrinkage is proportional to the nth power of soaking time with n = 0.20 for 4.4 μm and 1.5 μm powders and 0.33 for 0.78 μm powder. For the 0.78 μm powder at 1900° C, however, n decreases gradually as grain growth proceeds. The experimental activation energy for sintering is between 92 kcal/mole for 4.4 μm and 129 kcal/mole for 0.78 μm powder. Unlike this activated energy, the rate of sintering and the diffusion constant calculated from it increase drastically with decrease of particle size; the derived diffusion constant for 1.5 μm powder is 101 to 102 times larger than that of 4.4 μm powder, and for 0.78 μm powder the diffusion constant is estimated to be still higher. The particle-size dependence of parameter n and the diffusion constant seems to be caused by a variation in predominant diffusion mechanisms; namely, bulk diffusion in coarse powder and surface or grain-boundary diffusion in fine powder.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00549842
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Viscosity of concentrated styrene solutions of polystyrene (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 9-11 
    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: Viscosities of concentrated solutions of polystyrene of different intrinsic viscosities were measured at varying polymer concentration and temperature. By modifying Martin's equation, an empirical equation correlating the viscosity of the solution as a function of the polymer concentration, the intrinsic viscosity of the polymer, and temperature was obtained.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120102
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    Paper (German National Licenses)
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