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  • 1960-1964  (3)
  • Polymer and Materials Science  (3)
  • Life and Medical Sciences
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  • 1
    Electronic Resource
    Electronic Resource
    Transport of liquids in structurally modified polyethylene (1964)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 8 (1964), S. 897-933 
    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: Cast linear polyethylene films subjected to dry and solvent annealing display markedly different sorption and difusion barrier properties than do untreated films. The subsequent sorption of liquid o- and p-xylene and cis- and trans-acetylene dichloride per unit volume of amorphous polymer increases as the annealing temperature and/or treating solvent concentration increases. Integral diffusivities calculated from sorption and steady-state permeation rates show a monotonic increase with sorption per unit volume of amorphous polymer. The concentration dependence, however, is less marked than observed in similar systems at low permeant activity. Apparently the above treatment reduces the effective crosslinking imposed by the crystallites on the amorphous polymer chains through disentangling and incorporating some of these chains into crystallites. Thus the polymer is capable of a greater degree of swelling when brought into contact with a compatible liquid in a spite of a higher degree of crystallinity. The low concentration dependence of the diffusivities is probably due to heterogeneous distribution of excess permeant in a treated film. If the excess permeant were preferentially sorbed in regions of low polymer concentration then the above observations could be explained. Long-duration, osmotic stress-induced swelling and recrystallization have been cited to account for time-dependent permeation rates in treated and untreated films.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1964.070080229
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Some effects of cocatalyst structure on the anionic polymerization of ε-caprolactam (1964)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 8 (1964), S. 1363-1369 
    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: N-Acetyl, N-butyryl, N-stearyl, N-benzoyl, N-4-methoxybenzoyl, and N-4-nitrobenzoyl caprolactams were prepared and used as cocatalysts for the anionic polymerization of caprolactam. The results of these studies indicate that all of the cocatalysts used, except N-acetylcaprolactam, exert a steric effect which lowers both the rate and degree of polymerization. The N-benzoyl derivative appeared to be a slightly better cocatalyst than the N-4-methoxybenzoyl derivative. This may be due to the fact that the N-benzoyl group is the more electron-attracting group. N-4-Nitrobenzoylcaprolactam was unstable under the reaction conditions employed.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1964.070080326
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Carriers and unpaired spins in some organic semiconductors (1964)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 2 (1964), S. 2787-2806 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Semiconduction and electron spin resonance studies on a number of conjugated polymers representative of the polyacetylenes, the polybenzimidazoles, and the polyacene quinone radical polymers were made. Observed resistivities ranged from 270 to 1016 ohm-cm. at room temperature. These and the spin concentrations, the relaxation times, and the energies of activation of conductance and spin concentration were found to be functions of the molecular structure. It was considered impressive evidence that impurity effects on the electronic properties of molecular solids are far less than those commonly observed with the covalently bonded semiconductors such as Ge and Si, for example. A detailed analysis was made of the carrier and free radical formation and life-times in these ekaconjugated molecular solids using a simple model.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1964.100020629
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    Paper (German National Licenses)
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