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  • 1995-1999  (9)
  • monodisperse  (4)
  • Chemistry  (3)
  • dynamic swelling method  (3)
  • micron-size  (3)
  • Key words Dynamic swelling method  (2)
  • 99.10.+g  (1)
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  • 1
    ISSN: 1090-6487
    Schlagwort(e): 85.25.Cp ; 74.50.+r ; 99.10.+g
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1435-1536
    Schlagwort(e): Key words Dynamic swelling method ; micron size ; monodisperse ; composite ; seeded polymerization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract  In order to develop the seeded polymerization technique utilizing the dynamic swelling method (DSM) proposed by authors for the production of micron-sized mono-dispersed “composite” polymer particles consisting of two kinds of polymers, the seeded polymerization for the dispersion of ethyl methacry-late (EMA)-swollen PS particles prepared utilizing DSM was carried out. Monodispersed PS/poly(ethyl methacrylate) (PEMA) composite particles having 7 μm in diameter were produced by the addition of NaCl to lower the solubility of EMA in medium and by the addition of CuCl2 as a water-soluble inhibitor to depress the by-production of submicron-sized PEMA particles.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1435-1536
    Schlagwort(e): Key words Morphology ; composite particles ; micron-size ; seeded polymerization ; dynamic swelling method
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract  Micron-sized mono-dispersed polystyrene (PS)/poly(n-butyl methacrylate) (PBMA) composite particles (PS/PBMA=2/1 by weight) having a heterogeneous structure in which many fine PBMA domains dispersed in a PS matrix near the particle surface were produced by seeded polymerization of n-butyl methacrylate (BMA) of which almost all had been absorbed by 1.8 μm-sized monodispersed PS seed particles utilizing the dynamic swelling method. The morphology was varied by changing the PS/BMA ratio and polymerization temperature. It was concluded that the swelling state of 2 μm-sized BMA-swollen PS particles in the seeded polymerization process is one of the important factors to control the morphology of the composite particles.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1435-1536
    Schlagwort(e): Composite polymer particles ; seeded polymerization ; dispersion polymerization ; morphology ; dynamic swelling method
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Three kinds of micron-sized monodispersed polystyrene (PS)/poly(n-butyl methacrylate) (PBMA) composite particles (PS/BMA=2/1, wt. ratio) were produced by two kinds of seeded polymerizations ofn-butyl methacrylate (BMA) in the presence of about 2 μm-sized monodispersed PS particles, and their morphologies were examined. One was produced by a seeded dispersion polymerization where almost monomers and initiators exist in an ethanol/water (1/1, w/w) medium. The others two were produced by seeded polymerizations utilizing the dynamic swelling method, where almost monomers exist in the PS seed particles, with 2,2′-azobisisobutyronitrile initiator in the monomer-swollen particles and with 2,2′-azobis [2-(2-imidazolin-2-yl)propane] initiator in an ethanol/water (1/5, w/w) medium. In the former polymerization, the produced composite particles had a core-shell structure consisting of a PS-core and a PBMA-shell, whereas in the latter two polymerizations, they had a POO (Polymeric Oil-in-Oil) structure consisting of a PS-matrix and many PBMA-domains, regardless of the location of initiator in the systems. From these results, it is concluded that the location of BMA monomer in the seeded polymerization systems with micron-sized monodispersed PS seed particles greatly affects the morphologies of produced PS/PBMA composite particles.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1435-1536
    Schlagwort(e): Key words Composite polymer particles ; core/shell ; seeded dispersion polymerization ; morphology ; monodisperse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract  Micron-sized monodispersed polymethyl methacrylate (PMMA)/polystyrene (PS) (PMMA/PS=2/1, wt ratio) composite particles consisting of PMMA-core and PS-shell were successfully produced by seeded dispersion polymerization of styrene in a methanol/water medium in the presence of about 2 μm-sized monodispersed PMMA particles. From the view point of thermodynamic equilibrium, such a morphology is difficult to form by usual seeded polymerization in a polar medium such as water. It is concluded that seeded dispersion polymerization in which almost all monomers and initiators exist in the medium has an advantage to produce core/shell polymer particles in which polymer layers accumulate in their order of the production regardless of the hydrophobicity of polymers, because of high viscosity in polymerizing particles.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    ISSN: 1435-1536
    Schlagwort(e): Key words Dynamic swelling method ; cross-linked polymer particles ; monomer adsorption ; micron-size ; monodisperse ; snow-man shape
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Micron-sized, monodispersed highly styrene-“adsorbed” particles having snow-man shape were prepared by the dynamic swelling method (DSM) with tightly cross-linked polymer seed particles as follows. First, 3.8 μm-sized monodispersed polystyrene (PS)/ poly(divinylbenzene) (PDVB) (PS/PDVB = 1/10 wt. ratio) composite particles produced by seeded polymerization utilizing DSM were dispersed in an ethanol/water (6/4, w/w) solution dissolving styrene monomer, and poly(vinyl alcohol) as a stabilizer. Second, water was subsequently added to the dispersion with a micro-feeder at a rate of 2.88 ml/h at room temperature. The cross-linked seed particles adsorbed a large amount of styrene onto the surfaces and resulted in mono-dispersed highly styrene-“adsorbed” snow-man shape particles having about 10 μm in diameter.
    Materialart: Digitale Medien
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  • 7
    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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  • 8
    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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  • 9
    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
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