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Volume 50, Issue 4
Displaying 1-19 of 19 articles from this issue
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Shiro KOBAYASHI, Hiroshi UYAMA1993 Volume 50 Issue 4 Pages 209-221
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSThis article describes preparations of monodisperse polymer particles having poly (2-oxazoline) chains on the surface. The particles were prepared by dispersion copolymerization, soap-free emulsion copolymerization, or emulsion copolymerization using Poly (2-oxazoline) macromonomer. The macromonomer acted as acomonomer as well as a stabilizer or an emulsifier. ESCA analysis showed that poly (2-oxazoline) chains were locally present on the surface.View full abstractDownload PDF (2968K) -
Tohei YAMAMOTO, Minoru HANATANI, Kuniharu HIROTA, Hiroyuki KISHIBE, Os ...1993 Volume 50 Issue 4 Pages 223-225
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSInitiator-free photo-emulsion polymerization of vinyl propionate (VPr) and its copolymerization with vinyl acetate (VAc) were carried out in aqueous media at 0°C by using polyoxyethylene nonyl phenyl ether sodium sulfate as an emulsifier. In each case, poly (vinyl propionate) (PVPr) or the copolymer was obtained in a good yield. The average degree of polymerization (Pn) of poly (vinyl alcohol) (PVA) obtained by saponification of PVPr was not high, and the ratios of isotactic triad (I), heterotactic triad (H), and syndiotactic triad (S) were 18.5, 49.6, and 31.6%, respectively. Pns of PVA's from the copolymers were higher than those from PVPr's, and the ratios of the tacticites of PVA's from the copolymers varied with varying feed monomer compositions.View full abstractDownload PDF (538K) -
Masafumi KAMIYAMA, Kikuhiko KOYAMA1993 Volume 50 Issue 4 Pages 227-233
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSA procedure is described for preparing polymer microspheres by suspension polymerization. Preparation of composite microspheres with inorganic material is also described. The following suspension process is proposed: monomer and water phases, held in separate vessels, are fed at an accurate rate to the disperser. Particles from 2 to 20 μm of mean diameter with narrow size distribution are obtained. Suspension of the monomer phase in which inorganic materials are dispersed yields composite polymer particles. Size distribution is not affected by the composite materials.View full abstractDownload PDF (1735K) -
Norio TSUBOKAWA, Kazuhiro FUJIKI, Tohru SASAKI1993 Volume 50 Issue 4 Pages 235-241
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSTo prepare a branched polymer-grafted carbon black with a high percentage of grafting, the postgrafting of polyesters from previously grafted polymer chain on the carbon black surface was investigated. For the initiation of postgraft polymerization from grafted polymer chains on the carbon black surface, poly (potassium acrylate) (PPA) and poly (styrene-co-PA) were grafted onto the carbon black surface by the polymerization and copolymerization of the corresponding vinyl monomers initiated by azo groups introduced onto the surface. The anionic ring-opening alternating copolymerizations of epoxides with cyclic acid anhydrides were successfully initiated by pendant potassium carboxylate groups of grafted PPA and poly (styrene-co-PA) on the carbon black surface. During the polymerization, the corresponding polyesters were effectively grafted from these grafted polymer chains to give branched polymer-grafted carbon black with a high percentage of grafting; the percentage of grafting of polyester onto PPA was determined to be 17.1-116.5%. The rate of the postgraft polymerization of epoxides with cyclic acid anhydrides and grafting of polyester were remarkably affected by the structure of grafted PPA and poly (styrene-co-PA) and by the solubility of these grafted polymer chains in the polymerization system. The branched polymer-grafted carbon black with a high percentage of grafting produced a stable colloidal dispersion in organic solvents.View full abstractDownload PDF (1185K) -
Kazuhiko TAKAHASHI, Shigeo MIYAMORI1993 Volume 50 Issue 4 Pages 243-250
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSDispersion polymerizations of methacrylic acid esters (RMA) were investigated to prepare polymeric particles in the micron size range. In the polymerization of methyl methacrylate, microspheres with narrow size distribution were produced using polyvinylpyrrolidone as the dispersing agent without any co-stabilizers in methanol. This procedure was utilized for dispersion polymerization of other monomers. The mixed hydrophilic solvents composed of good and poor solvents for the polymers were used. For six monomers, using different sorts and compositions of solvents, microspheres were formed in the 1-10μm size range. The higher the solubility of polymer is, the larger the particle size is. In the polymerization, the followings are observed. 1) The microspheres whose size is in the 3-5 μm size range have rather narrow size distribution. 2) The larger the particle size is, the lower the molecular weight of polymer is. 3) The particle size is not necessarily a function of the solubility parameter of mixed solvents.View full abstractDownload PDF (2547K) -
Kazuhiko TAKAHASHI, Shigeo MIYAMORI1993 Volume 50 Issue 4 Pages 251-257
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSEffects of polymerization conditions on particle size were investigated in dispersion polymerization of methyl methacrylate in mixed hydrophilic media with a dispersing agent, polyvinylpyrrolidone. As a result, a correlation of the particle size with the ultimate molecular weight of the polymer was found in the polymerization under various conditions. The larger the size of particle is, the lower the molecular weight of polymer is. In spite of this phenomenon, the paticle sizes were not determined by the molecular weight of polymers alone. Furthermore, particle size is varied with the amount of dispersing agent, and relationship between the particle size and molecular weight of polymer was not unequivocal.View full abstractDownload PDF (1191K) -
Masato NAKAMURA, Ryuichi FUJINO, Mikio IKEDA1993 Volume 50 Issue 4 Pages 259-261
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSArtificial support material for use in passive agglutination immunoassay was prepared from the complex coacervation of gelatin and gum arabic. The gelatin particles with a diameter of 2.5 gm and with a zeta potential of-15 mV at an ionic strength of 0.10, pH 7.2 were appropriate for use in passive agglutination immunoassay. Red, blue, and purple colored-gelatin particles were obtained by changing the dye. Thus, the color, size, and electrophoretic mobility of the gelatin particles prepared from the complex coacervation tecnique were controlled to some extent and the gelatin particles were found to be suitable for use in passive agglutination immunoassays.View full abstractDownload PDF (940K) -
Katsutoshi NAGAI, Hiroaki KATAOKA, Noriyuki KURAMOTO1993 Volume 50 Issue 4 Pages 263-270
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSPolymer encapsulation of porous, silica gel particles by radical polymerization of styrene (ST) with potassium persulfate (KPS) in the presence of a cationic surface-active monomer in aqueous system was investigated. The surface-active monomers used here were quaternary salts (C8Br, C12Br and C16Br, mainly C12Br) of dimethylaminoethyl methacrylate with n-alkyl bromide having 8, 12, and 16 carbon atoms, respecitvely. The cationic monomer not only adsorbed onto silica gel particles but also formed an oil-soluble salt with KPS, which deposited onto adsorbed layers of the cationic monomer on the surface of the particles. The polymerization of ST solubilized into the adsorbed layers of cationic monomer was found to afford polymer-encapsulated particles with little formation of the latex polymer. The surface coverage of the resultiong particles increased with increase in the polymer content and nearly completely encapsulated particles were also obtained by the present encapsulation method.View full abstractDownload PDF (1324K) -
Shinji WATANABE, Seiichi NAKAHAMA, Kazuo YAMAGUCHI1993 Volume 50 Issue 4 Pages 271-277
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSLatices having phospholipid on the surface were produced as a stable biomembrane model by seeded emulsion polymerization of styrene, where polystyrene latex and a polymerizable phospholipid were employed as a seed particle and an emulsifier, respectively. The latex diameter and the density of phospholipid bound on the surface were controllable by feeding ratios of styrene monomer and phospholipid to the seed particle. Total amount of the lipid copolymerized with styrene was determined by ICP atomic emission spectroscopic (ICP-AES) measurement of the emulsion produced. The amount of the lipid bound on the latex surface was analyzed by ICP-AES measurement of hydrolyzed phospholipid and by XPS measurement of the dried latex. From the results of the phosphorus analyses, it was found that most of the lipid copolymerized with styrene localized on the latex surface. The latex bearing both mercapto groups and phospholipid was also produced in a similar manner using the seed latex having isothiuronium salt, which was hydrolyzed with alkali to mercapto groups after polymerization. Surface characterizations were similarly conducted to reveal that both the mercapto groups and phospholipid were bound on the surface of the latex.View full abstractDownload PDF (1711K) -
Kazutoshi TERADA, Hirotoshi MIYAZAKI, Mototsugu YOSHIHARA, Toshiaki SA ...1993 Volume 50 Issue 4 Pages 279-286
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSUsing thiolacetic acid as a chain transfer agent in radical polymerization of styrene, polystyrene having a thioacetate group at one end of the chain (PSt-SAc) was obtained. Transesterification reaction of the thioester group with methanol afforded polystyrene having a mercapto group at one end (PSt-SH). Vinyl acetate was polymerized in the presence of PSt-SH, and an A-B type block copolymer (PSt-b-PVAc) was obtained. Dispersion polymerization of styrene was performed in ethanol using the block copolymer (PSt-b-PVAc) thus obtained or a partially hydrolyzed block copolymer [PSt-b-P (VA/VAc) ]. Polystyrene (PSt) particles of 0.3-417 pm average diameter with relatively sharp particle size caused coagulation in the course of polymerization. With an increase in the amount of the block copolymer, particle diameters decreased. After the middle stage of the polymerization the particles grew with the almost constant number of particles.View full abstractDownload PDF (1837K) -
Yukihiko NAKA, Yukio YAMAMOTO1993 Volume 50 Issue 4 Pages 287-293
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSUltrasonic vibration during radiation-induced polymerization of diethyleneglycol dimethacrylate in ethyl acetate gives doublet nonspherical particles. The particles were effectively prepared by 10-min ultrasonic vibration at the middle of 2h period of the polymerization by r ray irradiation (4 kGy h-1). The contact of two spheres by the ultrasonic vibration and the following accumulation of polymer chains on the particle resulted in the nonspherical particles. The nonspherical shape supports the proposed “cross-linking promotion polymerization” mechanism for microsphere growth. The polymer chains generated in the liquid phase are drawn into the particle surface by the cross-linking reaction.View full abstractDownload PDF (2367K) -
Shuntaro HOSAKA, Kumiko MIURA, Sanae MASUKO, Yasuo MURAO1993 Volume 50 Issue 4 Pages 295-302
Published: April 25, 1993
Released on J-STAGE: November 29, 2010
JOURNAL FREE ACCESSCarboxyl or mercapto groups were introduced into microparticles of glycidyl methacrylate copolymenrs. When gycidyl methacrylate, methacrylic acid, and a glycol dimethacrylate were copolymerized in an organic medium such as ehyl propionate, the copolymer precipitated into microparticles. The content of carboxyl groups in the copolymers was found to be almost identical with that in the monomer mixture. Alternatively, carboxyl groups were introduced into microparticles by the addition of thioglycolic acid to the epoxy groups of glycidyl methacrylate copolymers. The resulting microparticles contained over 1meq/g of carboxyl groups. Direct treatment of the microparticles of the copolymer of glycidyl methacrylate, 2-hydroxyethyl methacrylate, and tri (ethylene glycol) dimethacrylate with dithiothreitol resulted in the introduction of sulfur into the copolymer up to 8.8%, while successive treatment of the same microparticles with sodium thiosulfate and dithioerythritol gave microparticles containing 5.5% sulfur. The mercapto group content of the latter was determined to be 0.094meq/g. Although as little as 0.14% sulfur was detected in the microparticles treated with hydrogen sulfide, an enough amount of human γ-globulin, 5.3 mg/m2, was immobilized using succinimidyl 4- (maleimidomethyl) cyclohexanecarboxylate as a binder.View full abstractDownload PDF (2094K) -
Kohji YOSHINAGA, Kenji NAKANISHI, Kenichi NAGAO, Taketoshi KITO1993 Volume 50 Issue 4 Pages 303-308
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSIntroductions of functional group, mainly amino group, on the surface of poly (styrene) -coated monodispersed colloidal silica particles (PST/Sio2) were investigated. Although surface nitration and successive reduction of PST/Sio2composite led to introduction of amino group, the silica core of the composites was spoiled by strong acids during the reactions. Radical polymerization of styrene (ST) and divinylbenzene (DVB) with chain transfer reagent, having amino or carboxyl group, in silica colloid-ethanol solution gave dispersible PST/Sio2 composites having the functional group. However, the surface amino groups were not able to react with poly (methyl methacrylate) (PMMA-COOH) having a carboxyl end group, so that most of them were apparently buried in the PST network. Surface chloromethyl group on polymer/Sio2 composite, prepared by copolymerization of ST, DVB and chloromethylstyrene in the silica colloid solution, was converted to amino group via aminolysis of the phtalimide. The amino group formed was shown to be effective for binding PMMA-COOH by condensation.View full abstractDownload PDF (1343K) -
Teruaki ASHIHARA, Kenichiro ISOMOTO, Ryozo ORITA1993 Volume 50 Issue 4 Pages 309-318
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSPollution-free waterborne emulsion sadhering to polypropylene (PP) without defatting by 1, 1, 1-trichloroethane (TCE) were synthesized and these properties were measured. The microsuspension polymerization was used with the system of chlorinated PP (CPP) /macromonomer (Mc) /monomer (s) or (CPP/) monomers. The results showed that 1) emulsions synthesized with 2-ethylhexyl methacrylate (EH) or cyclohexyl methacrylate (CH) as a base monomer are a stable and compatible multi-component system, 2) these particles are O. 5-0. 8μm in diameter, 3) these dried emulsion films adhere fully to PP substrate.View full abstractDownload PDF (1791K) -
Akira YOSHIMATSU, Tukasa ITO, Akihiro KONDO, Rikio TSUSHIMA1993 Volume 50 Issue 4 Pages 319-325
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSA novel seeded polymerization method (“Accelerated Molecular Diffusion Method”) was developed by improving the molecular diffusion process. A seed particles dispersion and DVB (divinylbenzene) /iso-amyl acetate/benzoyl peroxide mixed emulsion were prepared separately. A monomer emulsion, which was homogenized with ultrasonic irradiation, was added to the seed (-2μm) dispersion, portion by portion, with stirring over period of 3-4h. Swelling of seed particles occurred with a swelling ratio of about 20 to 300 fold, responding to the added monomer weight. Micron-size polymer particles (4-20 μm) were obtained after polymerization (80°C). The fact that iso-amyl acetate accelerates the diffusion of DVB monomer from DVB/iso-amyl acetate emulsion droplets was discussed on the basis of the molecular diffusion process. iso-amyl acetate would play important roles of l) making DVB droplets fine and stable, and 2) destabilizing smaller DVB droplets after iso-amyl acetate completely diffuses into seed particles.View full abstractDownload PDF (2117K) -
Chiaki AZUMA, Hiroshi HIRAYAMA1993 Volume 50 Issue 4 Pages 327-335
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSSol-gel reactions of the ternary monomer system consisting of tetraethoxysilane (TEOS), methyltriethoxysilane (MTEOS) and dimethyldiethoxysilane (DMDEOS) have been carried out in methanol or ethanol in the presence of ammonia as a catalyst in order to prepare silica-silicone hybrid super-micro-gel. The reaction in the methanol system proceeds more rapidly and quantitatively than that in the ethanol system, but it tends to yield insoluble products. The soluble products are the super-micro-gel particles with the particle diameter in the range of 10-30nm. The insoluble products are caused by the aggultination of the super-micro-gel particles. A threshold value exists for the overall rate of the reaction yielding the insoluble products. For higher rates than that, the reaction yields the insoluble products. The maximum yield of the insoluble products is less than 60% and the soluble products come from the reaction of only TEOS and MTEOS. In the case of the binary monomer system consisting of TEOS and MTEOS, the reaction yields the soluble products quantitatively. The initial thermal decomposition temperature of the products obtained from the reaction of the ternary monomer system decreases to 270°C with increasing yield, the weight loss by heating until 500°C is about 15%.View full abstractDownload PDF (1494K) -
Kunio FURUSAWA, Kazuomi NAGASHIMA, Chikai ANZAI1993 Volume 50 Issue 4 Pages 337-342
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSTo prepare composite particles with multilayers comprised of usual latex (2a=180-900 nm), NiO·ZnO·Fe2O3particles (2a=20nm), and polystyrene layer, based on heterocoagulation and encapsulation polymerization, the synthetic conditions have been investigated as the functions of pH in the medium and their particle size ratio. Regular heterocoagulates, which are made up of many magnetic particles regularly adhering to latex surface, were generated under the suitable medium conditions (pH 2.5) from these mixed suspensions. Encapsulation conditions of the heterocoagulates with polystyrene via emulsion polymerization were also examined. Encapsulation is promoted greatly by the existence of an adsorption layer of sodium oleate on the heterocoagulates. This made uniform composite particles with multilayers. The total sizes of composite particles with multilayers can be controlled freely by selecting latex particles with different sizes as the core.View full abstractDownload PDF (1850K) -
Kunio FURUSAWA, Kazuomi NAGASHIMA, Chikai ANZAI1993 Volume 50 Issue 4 Pages 343-347
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSSuitable Conditions to prepare regular composite fine particles which were comprised of organic and inorganic compounds were investigated using polystyrene lattices (2a=180nm) and a-alumina powders with different particle sizes (2a=1100nm, 850nm, and 400nm), based on heterocoagulation theory. It is apparent that under suitable conditions (medium pH=3-4, particle number ratio of latex and a-alumina≥ 300/1), the heterocoagulates generated from their mixtures were comprised of regular composite particles. These were made of latex particles adhering on a-alumina particles in the core. The fraction coverage of lattices increased with decreasing the particles size of alumina. Further, the behavior was influenced dramatically by the concentration of alumina particles in the mixing process; a ragular composite can be generated only from the diluted suspensions of ca. 0.2 wt%.View full abstractDownload PDF (1666K) -
Shigeki CHUJO, Masahiro RIKUICAWA, Kohei SANUI, Naoya OGATA1993 Volume 50 Issue 4 Pages 349-352
Published: April 25, 1993
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSRadical polymerization reaction of styrene was carried out in mixed solvents of ethanol and n-hexane in the presence of poly (methyl vinyl ether) (PMVE) which was used as a matrix polymer to control its morphology in the polymer solution where styrene monomer might be concentrated. Size and dispersity of the resulting polystyrene microspheres could be controlled by changing morphology of the matrix polymer which was caused by the ratio of ethanol to n-hexane.View full abstractDownload PDF (880K)
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