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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Colloid & polymer science 274 (1996), S. 433-438 
    ISSN: 1435-1536
    Schlagwort(e): Dynamic swelling method ; hollow ; micron-size ; monodisperse ; cross-linking ; seeded polymerization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Micron-sized monodispersed cross-linked polymer particles having one hollow in the inside were produced by seeded polymerization for the dispersion of (toluene/divinylbenzene)-swollen PS particles prepared utilizing the dynamic swelling method which the authors proposed. In order to control the hollow size, the weight ratio of toluene/PS was changed in the range of 5∼20. The hollow size increased with an increase in the weight ratio. Even if benzene and xylene were used in place of toluene, similar hollow particles were produced, though the hollow size was affected by their solubility in water.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Colloid & polymer science 275 (1997), S. 992-997 
    ISSN: 1435-1536
    Schlagwort(e): Key words Dynamic swelling method ; hollow ; micron-size ; monodisperse ; cross-linking ; formation mechanism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract  Recently, the authors reported that micron-sized monodispersed cross-linked polymer particles having a single hollow in the inside were produced by seeded polymerization for the dispersion of (toluene/divinylbenzene)-swollen polystyrene (PS) particles prepared utilizing the dynamic swelling method which the authors had proposed. In this article, the particles at various conversions of the seeded polymerization were observed with an optical microscope in detail. From the obtained results, the formation mechanism of the hollow structure is suggested as follows. As seeded polymerization proceeds, poly-divinylbenzene (PDVB) molecules precipitated in the swollen particle are trapped near the interface and gradually pile at the inner surface, which results in a cross-linked PDVB shell. PS which dissolves in the swollen particles is repelled gradually to the inside. After the completion of the polymerization, toluene in the hollow evaporates by drying, and PS clings to the inner wall of the shell uniformly.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Colloid & polymer science 267 (1989), S. 193-200 
    ISSN: 1435-1536
    Schlagwort(e): Polymer emulsion ; polymer microsphere ; micron-size ; chloromethyl group ; dispersion polymerization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Micron-size monodisperse polymer microspheres having chloromethyl groups thereon were prepared by two-step polymerization process as follows. First, micron-size monodisperse polystyrene particles were prepared by dispersion polymerization with 2,2′-azobisisobutyronitrile as initiator in ethanol-water medium in the presence of poly(acrylic acid) as stabilizer under various conditions. Secondly, in the presence of the 1.9-Μm monodisperse polystyrene particles produced under the optimum conditions, seeded copolymerization for styrene and chloromethyl styrene was carried out. The seeded copolymerization proceeded smoothly without producing new particles, and it was confirmed by x-ray photoelectron spectroscopy that the chloromethyl group existed more at the surface of the produced microsphere than at that of film cast from the benzene solution in which the microspheres were dissolved.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1435-1536
    Schlagwort(e): Anomalous particles ; emulsion polymerization ; heterocoagulation ; composite polymer particles ; morphology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Variation of surface unevenness of anomalous composite polymer particles produced by the “stepwise” heterocoagulation, which we had suggested in previous articles, of small cationic polymer particles onto large anionic polymer particle (LP) by heat treatment was examined with transmission and scanning electron microscopes. When the anomalous polymer emulsion was kept at higher temperature than the glass transition temperature ofLP, the particle surfaces were continuously changed from uneven to smooth state with the treatment time.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Colloid & polymer science 274 (1996), S. 428-432 
    ISSN: 1435-1536
    Schlagwort(e): Multihollow particles ; emulsion polymerization ; morphology ; carboxyl group ; transition temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Submicron-sized multihollow styrene-methacrylic acid (92.6/7.4, molar ratio) copolymer particles having high transition temperature above 100°C were produced by using the stepwise alkali/acid method proposed by the authors. The original particles were prepared by emulsion copolymerization of styrene and methacrylic acid. The effects of pH, temperature and time in the alkali treatment process as the first step on the multihollow structure were clarified under the same acid treatment conditions.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Colloid & polymer science 274 (1996), S. 520-524 
    ISSN: 1435-1536
    Schlagwort(e): Composite polymer particle ; emulsion polymerization ; morphology ; anomalous shape ; phase separation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Recently, the authors found that anomalous polystyrene/polybutyl acrylate composite particles, whose surfaces had many dents, were produced by emulsifier-free seeded emulsion polymerization of butyl acrylate with polystyrene seed particles. Such a particle was named a “golf ball-like” particle. In this article, the morphology and the formation mechanism of the golf ball-like composite polymer particles were studied.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Colloid & polymer science 272 (1994), S. 933-937 
    ISSN: 1435-1536
    Schlagwort(e): Multihollow particle ; emulsion polymerization ; emulsion ; latex ; morphology ; carboxyl group
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract The effects of pH, temperature and time in the acid-treatment process on the multihollow structure formed within submicron-sized monodispersed polymer particles by the stepwise alkali/acid method proposed by the authors were examined in detail. The original particles were produced by emulsifier-free emulsion terpolymerization of styrene, butyl acrylate, and methacrylic acid. It was clarified that the number and the size of hollows per particle were drastically changed by the acid treatment conditions as well as those in the alkali treatment process.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    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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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Colloid & polymer science 275 (1997), S. 82-85 
    ISSN: 1435-1536
    Schlagwort(e): Key words Multi-hollow particle ; emulsion polymerization ; morphology ; carboxyl group ; alkali swelling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract  The effects of molecular weight, particle diameter and cooling condition on the formation of multi-hollow structure formed within submicron-sized styrene-methacrylic acid copolymer particles by the “alkali/cooling method” proposed by the authors were examined and the formation mechanism was proposed. The original particles were produced by emulsion copolymerization in the presence of n-octyl mercaptan as a chain transfer agent.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Colloid & polymer science 275 (1997), S. 634-639 
    ISSN: 1435-1536
    Schlagwort(e): Key words Multi-hollow particles ; emulsion polymerization ; morphology ; acid swelling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract  Recently, we reported that multi-hollow polymer particles can be prepared from carboxylated polymer particles by the stepwise alkali/acid method. In this article, an attempt was made to prepare similar particles from acid-swellable polymer particles by the stepwise treatment with acid and alkali, which was named the stepwise acid/alkali method. The acid-swellable particles were produced by emulsion terpolymerization of styrene, butyl acrylate, and dimethyl 2-amino ethyl methacrylate. The effects of initial pH value, temperature, and time in the acid and alkali treatment processes on the multi-hollow structure were examined.
    Materialart: Digitale Medien
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