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81.
82.
Preparation of block copolymer by atom transfer radical seeded emulsion polymerization 总被引:1,自引:0,他引:1
Masayoshi?OkuboEmail author Hideto?Minami Jian?Zhou 《Colloid and polymer science》2004,282(7):747-752
Poly(i-butyl methacrylate)-polystyrene block copolymer was successfully prepared in an aqueous medium by two-step atom transfer radical polymerization (ATRP), mini-emulsion- and seeded-ATRP, in which ethyl 2-bromoisobutyrate/CuBr/4,4-dinonyl-2,2-dipyridyl initiator system was used. The block copolymer had narrow molecular weight distribution (Mw/Mn=1.1) and the number-average molecular weight measured by gel permeation chromatography agreed with the calculated value.Part CCXLVIII of the series Studies on Suspension and Emulsion 相似文献
83.
Hideto Minami Zhaoqun Wang Tsuyoshi Yamashita Masayoshi Okubo 《Colloid and polymer science》2003,281(3):246-252
Thermodynamic simulation of the morphology of monomer-adsorbed, cross-linked polymer particles prepared by the dynamic swelling method which the authors proposed was conducted to clarify its thermodynamic stability from the viewpoint of the total interfacial free energy. By comparing it with experimental results reported in previous articles, it was found that the morphology was controlled thermodynamically. Snowman-shaped composite polymer particles having different morphologies were prepared by seeded polymerization of the monomer-adsorbed, cross-linked polymer particles, in which the polymer particles had different cross-linking densities. 相似文献
84.
Formation of ternary ion associates using diprotic acid dyes and its application to determination of cationic surfactants 总被引:1,自引:0,他引:1
A sensitive and selective method is described for the determination of cationic surfactants, such as benzethonium, benzalkonium, cetylpyridinium and trimethylstearylammonium, based on the formation and extraction of ternary ion associates with an acid dye (bromophenol blue or bromochlorophenol blue) and quinidine. Quinidine reacts with divalent anionic dyestuffs to form a bulky 11 complex anion, which is extractable into 1,2-dichloroethane as ternary ion associates with cationic surfactants in nearly neutral media. The ternary ion associate gives a blue product. Linearity of the calibration curve is improved and the extractability of the cationic surfactants is enhanced in the presence of quinidine. In addition, many other amines do not interfere with the determination. The blue ion associates can be used for the selective and sensitive spectrophotometric determination of cationic surfactants. 相似文献
85.
The addition of carbon radicals to glyoxylic imines was studied using zinc dust as a radical initiator. The zinc-mediated radical reaction of glyoxylic oxime ethers and hydrazones proceeded smoothly to give the alkylated products via a carbon-carbon bond-forming process in aqueous media. The reaction of the oxime ethers and hydrazones having an Oppolzer's camphorsultam group provided the corresponding alkylated products, which could be converted into enantiomerically pure alpha-amino acids. The diastereoselectivities observed in the reaction of hydrazones were better than those obtained in the reaction of oxime ethers. 相似文献
86.
Minami H Kobayashi H Okubo M 《Langmuir : the ACS journal of surfaces and colloids》2005,21(13):5655-5658
The influence of sodium dodecyl sulfate (SDS) on the shell formation of hollow polymer particles prepared by the SaPSeP method, which was proposed by the authors for the preparation of micrometer-sized hollow polymer particles, was investigated. A single hole was observed in the shell of the hollow particles prepared by seeded polymerization of micrometer-sized, monodisperse divinylbenzene/p-xylene droplets in aqueous medium in the presence of SDS at concentrations above 43.3 mM, which were prepared by the dynamic swelling method. The fraction of the hollow particles having a single hole in the shell and the area of the hole increased with the SDS concentration. 相似文献
87.
(1,5)-(-)-Karahana ether (8,8-dimethyl-2-methylene-6-oxabi-cyclo[ 3.2.1]octane) and (1,5)-(-)-karahana lactone (8,8-dimethyl-2-methylene-6-oxabicyclo [3.2.1]octan-7-one) were synthesized from ()-3-hydroxy-2,2-dimethylcyclo-hexanone. The natural karahana lactone was shown to be almost racemic (. 1.3 % e.e.). 相似文献
88.
Da-Bing Li Takuya Katsuno Keisuke Nakao Masakazu Aoki Hideto Miyake Kazumasa Hiramatsu 《Journal of Crystal Growth》2006,290(2):374-378
Influence of Si doping on the optical and structural properties of InGaN epilayers with different Si concentrations was investigated in detail by means of high-resolution X-ray diffraction (HRXRD), scanning electron microscope (SEM), Cathodoluminescence (CL) and photoluminescence (PL). It was found that a small amount of Si doping in InGaN could enhance luminescence intensity, improve the crystal quality of InGaN and suppress the formation of V-defects in InGaN. Further investigation by CL showed that V-defects act as nonradiative center, which lower the luminescence efficiency of InGaN. Based on above-mentioned results, one possible mechanism of influence of Si doping on the formation of V-defects in InGaN was also proposed in this paper. 相似文献
89.
Hiroyuki Hayashi Satoru Karasawa Akihiro Tanaka Keisuke Odoi Katsumi Chikama Hideto Kuribayashi Noboru Koga 《Magnetic resonance in chemistry : MRC》2009,47(3):201-204
High water‐soluble hyperbranched poly(styrene) (HPS) polymers carrying stable 2, 2, 6, 6‐tetramethylpiperidine‐1‐oxyl (TEMPO) radicals, HPS‐N‐TEMPO, HPS‐Im‐TEMPO, and HPS‐Im‐(TEMPO)2, were prepared in ca. 60% introducing yield. HPS‐N‐TEMPO and HPS‐Im‐TEMPO were determined to be nearly spherical shapes of the diameter of 2.4 ± 0.6 and 2.2 ± 0.6 nm, respectively, by transmission electron microscope (TEM) images. The values of water‐proton relaxivity, r1, at 25 MHz, 0.59 T, and 25 °C were 6.0, 5.2, and 14 mM?1 sec?1 for HPS‐N‐TEMPO, HPS‐Im‐TEMPO, and HPS‐Im‐(TEMPO)2, respectively. The spin‐lattice relaxation time (T1)‐weighted images in phantom were also observed. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
90.