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  • Polymer and Materials Science  (15)
  • Life and Medical Sciences  (6)
  • Acoustics  (1)
  • 1960-1964  (15)
  • 1955-1959  (7)
  • 1940-1944
  • 1
    Electronic Resource
    Electronic Resource
    Philadelphia : Wiley-Blackwell
    Journal of Cellular and Comparative Physiology 56 (1960), S. 169-188 
    ISSN: 0095-9898
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    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 faint emission of light by various classes and types of polymers when heated in the presence of oxygen, oxyluminescence, was studied by means of a photomultiplier tube and sensitive microammeter. Among the polymers with a carbon-carbon backbone, the polymers having the greater number of tertiary carbon atoms generally showed greater intensities of luminosity. Polystyrene was a notable exception to this generalization. The shape of the luminosity versus time curves varied with the type of polymer. It was also found that the emission of light did not stop instantly when the oxygen atmosphere was replaced by an inert gas, but rather followed an exponential type of decay. The rate of decay appeared to be different with different types of polymers. The intensities of luminescence and the times required to reach maximum or steady state luminescence were compared with oxygen uptake data for various polymers. In general there was a qualitative, but not necessarily quantitative correlation between the luminous intensities and polymer stabilities in the presence of oxygen.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 8 (1964), S. 997-1006 
    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 oxyluminescence of polypropylene and polyethylene stabilized with various amounts of 4,4′-thiobis(3-methyl-6-tert-butylphenol) were studied and compared with oxygen uptake data. It was found that there was a correlation, although not linear, between the two methods. In the case of the stabilized polypropylenes, a pronounced aging effect was noticed. The oxyluminescent behavior of stabilized polyethylene was somewhat different from that of stabilized polypropylene. The temperature coefficients of the oxyluminescence of polypropylene, polyethylene, nylon 6, polystyrene, polyurethane and polymethyl methacrylate were obtained. From these data the apparent activation energies for the light-emitting reaction were calculated. For the olefin polymers, these values are close to the activation energies of the oxidative degradation reaction obtained by other means. Both polyethylene and polymethyl methacrylate have different activation energies below their transition points as compared to higher temperature, indicating a different mode of reaction in the solid state from that occurring in the melt. An interesting transition luminescence, which was more pronounced in the absence of oxygen, was observed in the case of polyethylene.
    Additional Material: 4 Ill.
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  • 4
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 23 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 1 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 2 (1959), S. 198-202 
    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: Polymers and copolymers were prepared from the acetoxy derivatives of m- and p-hydroxybenzoic acids. Molecular weights of over 20,000 were obtained for poly(m-hydroxybenzoic acid) and copolymers containing up to 60% para isomer. These polyesters were crystalline, and the degree of crystallinity increased as the para isomer content was increased. Blocks of the high-melting, insoluble poly(p-hydroxybenzoic acid) tend to form in copolymers containing a high proportion of the para isomer because of the difference in reactivity of the two isomers. Copolymers containing at least 55% of the meta isomer are soluble in several classes of solvents. The copolymers do not have sharply defined melting points, but have softening temperatures ranging from 150°C. to over 300°C. Tensile strengths of approximately 10,000 psi and elongations of about 6% to 40% were obtained. The polymers were relatively stable to oxidative degradation, but not to hydrolysis.
    Additional Material: 3 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 4 (1960), S. 219-224 
    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: Attention is called to the variables effecting the extraction of polypropylene. Under controlled conditions, the extraction of polypropylene with first diethyl ether and then n-heptane will give reproducible results. It is necessary to extract with heptane in an atmosphere of nitrogen. The values obtained by the extraction procedure described are regarded as relative measures of the amounts of isotactic, stereoblock and atactic material present in a sample. Extraction with n-heptane alone by this procedure also gives the same value of relative isotacticity. Infrared studies showed that the ether soluble fractions were essentially atactic, while the n-heptane-soluble or stereoblock material possessed a degree of order corresponding to 20-40% isotactic polypropylene.
    Additional Material: 2 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 7 (1963), S. 959-969 
    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 initial stages of isotactic polypropylene oxidation were investigated by oxidizing at 130°C. to various extents up to 10 ml. of oxygen consumed per gram of polymer. The development of infrared absorption bands in the carbonyl regions was followed, as increasing amounts of oxidation occurred. The oxidation uptake curves showed that both autocatalytic rate and induction time depended primarily on the thickness of the sample, contrary to the case of polyethylene. This indicated the initiation process was primarily diffusion controlled for samples of the thickness range studied. The presence of copper shortened the induction times and increased the autocatalytic rate. In this case, the dependency of the induction time on thickness was less. Dielectric data showed that polypropylene became unsuitable electrically at about the point where the autocatalytic oxidation set in. It was also found that the effects of prior exposure to oxidative conditions were cumulative to a considerable extent, and thus resulted in shorter induction times.
    Additional Material: 6 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 47 (1960), S. 259-265 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Anhydrous lithium perchlorate is an effective catalyst for the polymerization of certain vinyl monomers. Evidence shows that it behaves more as a cationic catalyst than a radical type, but is much milder in action than the better known representatives of this type of catalyst. Other perchlorates and lithium compounds show only a fraction or none of the activity of anhydrous lithium perchlorate in initiating vinyl polymerization.
    Additional Material: 5 Tab.
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  • 10
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 57 (1962), S. 641-650 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of a variety of phenols on the rate and degree of polymerization of styrene has been studied. With 1-naphthol it is found that polystyryl radicals abstract the phenolic hydrogen atom, since 1-naphthol has a far greater effect on the rate and degree of polymerization than 1-deuteroxynaphthalene. Many phenols do not significantly retard the polymerization of styrene and transfer constants ranging up to 7.7 × 10-3 have been estimated for them. Other phenols, such as 1-naphthol, 4-methoxyphenol and 2,6-diisopropylphenol, significantly decrease the rate and degree of polymerization. Transfer constants for these retarders have been calculated, both from the rate data alone by means of the treatment of Jenkins and from molecular weight data. The estimated values depend on the assumptions made concerning the mode of disappearance of the retarder radicals produced in the transfer reaction. Most of the retarders investigated give transfer constants in the range 10-2 to 10-1 but catechol, tert-butylcatechol, and pyrogallol give larger values. An increased rate of polymerization observed in mixtures of styrene and some phenols is probably due to a higher rate of production of radicals by the initiator, azobisisobutyronitrile.
    Additional Material: 2 Tab.
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