Kobunshi Kagaku
Online ISSN : 1884-8079
Print ISSN : 0023-2556
ISSN-L : 0023-2556
Volume 24, Issue 263
Displaying 1-8 of 8 articles from this issue
  • Masanobu Taniguchi, Kazuo Ozaki, Nariyoshi Kawabata, Junji Furukawa
    1967 Volume 24 Issue 263 Pages 193-197
    Published: March 25, 1967
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    We have prepared diethyl -α- picolylaluminum (α-PA) by the reaction of diethylaluminum chloride with α-picolyllithium, and examined the catalytic activity of α-PA for the polymerization of various monomers. Like triethylaluminum, α-PA is slightly active for the polymerization of vinyl monomers, cyclic ethers, lactones and ketenes. However, α-PA is more active than triethylaluminum in the polymerization of acetaldehyde, yielding crystalline polyacetaldehyde in better yield than triethylaluminum. α-PA-TiCl4 system induces the polymerization of ethylene, although the catalytic activity of the system is lower tham that of Et3Al-TiCl4 system. The catalytic activity of α-PA-α-TiCl3 system is nearly equal to that of Et3Al-TiCl3 system for the polymerization of propylene, but α-PA-α-TiCl3 system gives isotactic polypropylene in better yield.
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  • I. Effect of Polymerization Conditions and Polymerization Mechanism
    Shunsuke Murahashi, Takao Niki, Takao Obokata, Heimei Yuki, Koichi Hat ...
    1967 Volume 24 Issue 263 Pages 198-202
    Published: March 25, 1967
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    The polymerization of methyl methacrylate by diethyl aluminum diphenylamide (Et2AlNPh2) was carried out in toluene at various temperatures. The rate of polymerization was remarkably increased with decreasing the polymerization temperature, showing maximum at -50°C. It decreased at the lower temperature. At a constant catalyst concentration the degree of polymerization was increased proportionally to the amount of polymer produced at the temperature ranging from -20 to -50°C. This suggests that the rates of chain transfer and of chain termination in the polymerization were very small in comparison with the rate of propagation.
    The polymerization system gave no ESR signal at room temperature and at -50°C. The UV spectrum of polymer showed that the polymer has a terminal Ph2N-group in the molecule. The copolymerization of MMA and styrene by this catalyst at 60°C gave a copolymer composition curve similar to that given by the radical copolymerization of these monomers, while the copolymerization at -20°C showed the composition curve being of anionic mechanism. These results suggest that the polymerization at low temperature was initiated by the scission of Al-N bond in Et2AlNPh2 and with anionic mechanism.
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  • Tadashi Yamaguchi, Yasuo Hata
    1967 Volume 24 Issue 263 Pages 203-208
    Published: March 25, 1967
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    The polymerization of methyl methacrylate with metallic sodium or potassium as a catalyst in trimethylamine was carried out.
    In the case of sodium as the catalyst, the rate of polymerization was proportional to catalyst concentration and monomer concentration. The overall activation energy was 3.0 kcal/mol. The molecular weight of polymers obtained was proportional to monomer concentration, but inversely proportional to catalyst concentration. The molecular weight increased with increase of conversion. Being different from polymerization of styrene, the stable living polymethyl methacrylate was not formed. When potassium was used instead of sodium, the rate of polymerization decreased.
    Block copolymer of styrene and methyl methacrylate, furthermore, was synthesized from living polystyrene and the properties of the block copolymers obtained were examined.
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  • Tadashi Yamaguchi, Yasuo Hata
    1967 Volume 24 Issue 263 Pages 209-214
    Published: March 25, 1967
    Released on J-STAGE: July 27, 2010
    JOURNAL FREE ACCESS
    The polymerization of styrene with metallic sodium as a catalyst in trimethylamine was carried out.
    The rate of polymerization was proportional to catalyst concentration and monomer concentration. The overall activation energy was 5.3kcal/mole. The molecular weight of polymers obtained was proportional to monomer concentration, inversely proportional to catalyst concentration and was independent to polymerization temperature. The molecular weight increased with increasing conversion. As the result of measurement of molecular weight distribution, molecular weight distribution wa srather sharp although this reaction has been carried out in heterogeneous system using metallic sodium. For instance, Mw/Mn (molecular weight 200000) was 1.24. The relation of the degree of polymerization vs. monomer concentration and catalyst concentration was represented by the following equation:
    and the formation of living polystyrene was suggested.
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  • Shizunobu Hashimoto, Yasuhiko Nagasuna
    1967 Volume 24 Issue 263 Pages 215-223
    Published: March 25, 1967
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    The preparation and properties of polyesters from 2, 6-dimethylol pyridine with aliphatic dicarboxylic acids and pyridine dicarboxylic acid derivatives with diols by melt or interfacial polycondensation have been studied. Polyesters from 2, 6-dimethylol pyridine with dimethylesters of aliphatic dicarboxylic acids were prepared by melt polycondensation. Polyesters from dimethyl isocinchomeronate, diphenyl isocinchomeronate, or 2, 6-dimethyl-3, 5-dicarbobethoxy pyridine with diols were prepared by melt polycondensation. All-aromatic polyesters were prepared from three kinds of pyridine dicarboxylic acid dichlorides with aromatic diols by interfacial polycondensation. The physical properties of these polyesters prepared, such as melting point, solution viscosity, melt spinnable property, and solubility, were measured. The all-aromatic polyesters prepared by interfacial polycondensation had high solution viscosity and rather high melting point, which is above 300°C.
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  • IV. Fracture of Single Crystals
    Kiyoshi Tsuboi, Takani Mochizuki
    1967 Volume 24 Issue 263 Pages 224-229
    Published: March 25, 1967
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    Polyvinyl alcohol (PVA) single crystals fractured by ultrasonic irradiation or by using a mortar are examined by electron microscope and X-ray diffraction. The X-ray patterns from fractured single crystals exhibit an increase in the half-widths. The absorption of Congo red or iodine on fractured single crystals is larger than that on unfractured crystals. Single crystals drawn on PVA film break along lines parallel to the corrugations. Further, single crystals deposited on a carbon coated grid are deformed by bending the grid to an appropriate curvature. Single crystals either break or are converted into fibers in which the b-axes are parallel to the axis of stretching.
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  • I. Synthesis and Optical Rotatory Dispersion of Poly-γ-methyl-glutamates
    Akio Nakajima, Toshio Hayashi
    1967 Volume 24 Issue 263 Pages 230-235
    Published: March 25, 1967
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    Poly-γ-methyl-L-glutamate (PMLG) and poly-γ-methyl-D-glutamate (PMDG) were synthesized by the NCA method, and fractionated. With fractionated samples, molecular conformation in several solvents was investigated by measuring the optical rotatory dispersion. It was found that poly-γ-methyl-glutamates exist in dichloroacetic acid and trifluoroacetic acid as a random coil, while in m-cresol, PMLG and PMDG are in righthanded and left-handed helical forms, respectively.
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  • II. Molecular Conformation of Poly-γ-methyl-L-glutamate in Various Two-Component Solvents
    Akio Nakajima, Toshio Hayashi
    1967 Volume 24 Issue 263 Pages 235-240
    Published: March 25, 1967
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    The molecular conformations of poly-γ-methyl-L-glutamate in various solvents were studied by viscosity and optical rotatory dispersion measurements, and helix-random coil transformation was discussed as a function of solvent composition. The mixed solvents used were dichloroacetic acid-m-cresol system, trifluoroacetic acid-acetic acid system, and mixtures of dichloroacetic acid and organic solvents, such as alcohols, carboxylic acids, halides, hydrocarbons, and other polar solvents. Many helix-solvents composed of twocomponent mixture were found in this study.
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