KOBUNSHI RONBUNSHU
Online ISSN : 1881-5685
Print ISSN : 0386-2186
ISSN-L : 0386-2186
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Volume 64, Issue 6
Displaying 1-9 of 9 articles from this issue
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Review Articles
  • Living Radical Polymerization
    —Current Status and Future Perspective—
    Takeshi YAMADA, Kazunori IIDA, Shigeru YAMAGO
    2007 Volume 64 Issue 6 Pages 329-342
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.329
    JOURNAL FREE ACCESS
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    Living radical polymerization (LRP) has attracted a great deal of attention recently from various viewpoints. This is not only because the development of new LRP methods is a scientific challenge, but also because LRP would allow the synthesis of high-valued functional polymeric materials with controlled macromolecular structures for nanosciences and technologies. This review summarizes and compares representative LRP methods developed during the past 15 years from the mechanistic viewpoint to understand their similarities and differences. Nitroxide-mediated living radical polymerization (NMP), atom transfer radical polymerization (ATRP), reversible addition fragmentation chain transfer radical polymerization (RAFT), and organotellurium-mediated living radical polymerization (TERP) are discussed. This review will be published as two sections. This first section deals with the definition of LRP, the historical background of its discovery, common reaction mechanisms, and the mechanism of NMP. The second section will describe mechanisms of ATRP, RAFT, and TERP, and recent topics and future perspective of LRPs.
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Comprehensive Papers
  • Kinetics of Microemulsion Polymerization
    Kiyoshi SUZUKI, Mamoru NOMURA
    2007 Volume 64 Issue 6 Pages 343-354
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.343
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    A kinetic model for microemulsion polymerization is proposed considering that the number of micelles is by far larger at any stage of the polymerization than the number of polymer particles or that of radicals in the system. The model assumes that every radical in the aqueous phase enters each micelle separately, propagates therein to form a polymeric radical, and transforms the micelle into a polymer particle. According to the model, propagation of a polymeric radical is stopped only by chain transfer reaction to a monomer or to a chain transfer agent, and the growth of polymer particle is stopped only by desorption of the resultant radical from the particle. The model predicts the rate of polymerization, the molecular weight distribution of produced polymer, the number and the size-distribution of polymer particles produced which agree well with those observed experimentally in the microemulsion polymerization of styrene. The lower rate of polymerization with oil-soluble initiators than with water-soluble initiators even under the same rate of radical production suggests that a pair of radicals generated in a small space such as a micelle or a polymer particle tend to terminate therein bimolecularly with each other.
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  • Optical Properties of Magnetic Colloidal Crystals
    Norihito SOGOSHI, Seiichiro NAKABAYASHI
    2007 Volume 64 Issue 6 Pages 355-360
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.355
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    Optical properties of magnetic colloidal crystals were studied to clarify the magnetic color tuning and to promote magneto optical devices. Magnetic particles of silica spheres containing iron oxide cores were synthesized using a 2-step synthetic procedure. Liquid phase colloidal crystals of the magnetic particles showed a remarkable color switching function on magnetization. Magneto-optical effects of magnetic colloidal crystals deposited on glass substrates were enhanced at the photonic band edge due to the reduced group velocity of light.
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Original Papers
  • Preparation of Micro-porous Polyethylene Membrane by 3-Component Melt-Process
    Haruyuki YONEDA, Hiroshi HACHIYA, Masayuki ADACHI
    2007 Volume 64 Issue 6 Pages 361-367
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.361
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    A separator for lithium ion secondary battery was made by PE-inorganic powder-solvent 3-component melt process. Phase separation was studied by a new torque method. The relationship between phase separation and membrane morphology was examined. The effects of extension on the morphology of the membrane was also examined. The rate phase separation of 3-component process was slower than that of 2-comonent process. Thus, even in liquid-liquid phase separation, no cell structures were found in the membrane. After phase separation, extension and extraction of inorganic powder and solvent were carried out. The puncture strength increased with extension.
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  • Preparation of Micro-Porous Polyethylene Membrane by 2-Component Melt-Process
    Haruyuki YONEDA, Takahiko KONDO
    2007 Volume 64 Issue 6 Pages 368-372
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.368
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    A separator for lithium ion secondary battery was made by PE-solvent 2-component melt process. The relationship between phase separation and membrane morphology was examined. The effects of extension on the morphology of the membrane was also examined. In liquid-liquid phase separation, cell structures were found in the membrane. The cell diameter increased with slower cooling and with decrease in alkyl chain length in dialkyl phthalates. In solid-liquid phase separation, no cell structures were found. After phase separation, extension and extraction of the solvent were carried out. The puncture strength increased with extension.
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  • Molecular Assembly and Blood Compatibility of Poly[2-(methacryloyloxy) ethyl phosphorylcholine-b-dimethylsiloxane] Block Copolymers
    Nobuyuki TANIGAWA, Kohei SHIRAISHI, Kazuo SUGIYAMA
    2007 Volume 64 Issue 6 Pages 373-379
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.373
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    Block copolymers, poly(MPC-b-DMS)-I~IV, were prepared by the radical polymerization of 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) initiated with an azo-initiator having polydimethylsiloxane chains (azo-PDMS) in the presence of 2-mercaptoethanol as a chain-transfer agent. From scanning probe microscope (SPM) measurements, poly(MPC-b-DMS) was found to form microphase- separated structures. The self-organization of poly(MPC-b-DMS) was analyzed by fluorescence and 1H NMR measurements. The critical micelle concentrations of poly(MPC-b-DMS) were 90—600 mg L−1. The blood compatibility of poly(MPC-b-DMS)-I~IV was evaluated from the Michaelis constant (Km) for the enzymatic reaction of thrombin and a synthetic substrate, S-2238. Km was found to be 0.10—0.16 mM.
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  • Study on Thermal Stability and Chemical Structure of Polyamide Blended with Small Amount of Cu
    Tsuyoshi ARAI, Tomonaga UENO, Takafumi KAJIYA, Tomoyuki ISHIKAWA, Kuni ...
    2007 Volume 64 Issue 6 Pages 380-386
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.380
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    The thermal stability and the chemical structure of Polyamide 66(PA66) blended with a small amount of copper have been studied. The thermal degradation of the blend with 35 ppm or more of copper was restrained and no strong influence of the concentration of copper was observed. The molecular weight of PA66 decreased by the thermal aging process but the amount of decrease of the blend was smaller than that of the non-blend. The water uptake of the blend increased. The chemical structure, which was observed by IR and NMR, changed slightly by blending with copper after aging at higher temperatures. Multiple items influenced the thermal stability of PA66 blended with a small amount of copper instead of just one. Namely, the main chain of PA66 is cut by heat and the degree of the cut is restrained by the copper. The diffusion time of copper atoms that disperse uniformly in the PA66 matrix is short enough to cover the individual amide groups and the effect enlarges the entire configuration of the PA66 chain to enhance the thermal stability.
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  • Nylon 6/Modified Butyl-Rubber Blend Systems with Heterogeneous Morphologies: Mechanical Properties and Changes in Chemical Structure
    Sho YOKOYAMA, Tatsuya ENOMOTO, Daisuke SAWAI, Tetsuo KANAMOTO
    2007 Volume 64 Issue 6 Pages 387-393
    Published: 2007
    Released on J-STAGE: October 01, 2007
    DOIhttps://doi.org/10.1295/koron.64.387
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    The mechanical properties, morphologies and chemical structures of PA6/BIMS blend systems with heterogeneous morphologies, prepared by blending moisturized PA6 with BIMS, were examined by stress-strain behavior, AFM, DSC, IR, and solid state 13C NMR spectroscopy. The stress-strain curves and AFM observations revealed that the recovery of strain in the PA6/BIMS blends strongly depends on their morphologies. The PA6/BIMS blends maintained sheet forms even after extraction of a large amount of PA6 from the blends with formic acid. The strain recovery of the residue improved with increasing the amount of extracted PA6 and approached that of neat butyl-rubber at the maximum extraction. The IR spectrum and the potassium iodide starch test suggested that a small amount of PA6, which could not be extracted with formic acid, remained on the surface of the BIMS particles. The solid state 13C NMR spectra of the PA6/BIMS blends revealed that chemical reactions occur between the amide groups of PA6 and the bromine groups of BIMS during the hot mixing, giving rise to graft copolymers of PA6 and BIMS.
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