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  • 1
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: A novel intrinsic photosensitive polyimide containing a diazo group in the main chain was prepared, and the quantum yield for the photocrosslinking reaction was determined to be 0.13 under air at room temperature by GPC measurement. The quantum yield for the photo-decomposition reaction of the diazo group was also determined to be 0.06. These values are higher by about two orders of magnitude than those for the photocrosslinking reaction of a benzophenone-containing polyimide, which is prepared from benzophenonetetracarboxylic dianhydride (BTDA) and methylene bis(2-ethylaniline) (DEDPM). The reaction was found to proceed via its singlet excited state to give a long-lived active intermediate, a carbene, which plays a great role in the increase in the photoreactivity. Characteristics of the photoreaction and the fluorescence behavior of a series of imide-substituted diphenyldiazomethanes were also investigated, showing that the reactivity of the diazo groups is not affected by the existence of charge transfer structures of the imide groups.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 0887-624X
    Schlagwort(e): dynamic swelling method ; particle ; monodisperse ; micron-size ; seeded polymerization ; emulsion polymerization ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: For the purpose of extending the size range of polymer seed particles used in “dynamic swelling method” (DSM), first it was verified theoretically that the submicron-sized polymer particles produced by emulsion polymerization can also absorb a large amount of monomer by DSM in both equilibrium and kinetic control states. Next, on the basis of the theoretical results, experimentally about 2.6 μm-sized styrene-swollen polystyrene (PS) particles were prepared utilizing DSM in the presence of 0.64 μm-sized monodispersed PS seed particles produced by emulsifier-free emulsion polymerization. Moreover, 2.5 μm-sized monodispersed PS particles were produced by the addition of cupric chloride as a water-soluble inhibitor to depress the by-production of submicron-sized PS particles in the seeded polymerization at 30°C with 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) initiator. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2513-2519, 1998
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 1025-1031 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Recently, we suggested a novel swelling method to make polymer seed particles absorb a large amount of monomer prior to the seeded polymerization for preparing monodispersed polymer particles having diameter above 5μm, which we named the “dynamic swelling method.” This article discusses the thermodynamic background of this method, both theo-retically and experimentally. © 1996 John Wiley & Sons, Inc.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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