Kobunshi Kagaku
Online ISSN : 1884-8079
Print ISSN : 0023-2556
ISSN-L : 0023-2556
Volume 22, Issue 245
Displaying 1-5 of 5 articles from this issue
  • III. Influence of Molecular Weight and Molecular Weight Distribution on Flow Behavior
    Kenji Kamide, Yoshihiko Inamoto, Kunio Ohno
    1965 Volume 22 Issue 245 Pages 529-538
    Published: September 25, 1965
    Released on J-STAGE: February 20, 2012
    JOURNAL FREE ACCESS
    Seven fractions of isotactic polypropylene ranging in molecular weight from 1.1×105 to 7.7×105 and five blends with molecular weight of approximately 1.7×105 were used to investigate the melt flow behavior at 250°C through capillary. A non-newtonian parameter, N(=d ln η/d ln D) increases with increasing molecular weight and molecular weight distribution (MWD), and another parameter proposed in this paper a(=d{1/ln η}/dln τ) strongly depends upon MWD. The three methods of determining the zero-shear stress viscosity η0 were discussed.η0 from method 1 (plots of ln 1/4ηa vs.τ) and method 2 (plots of In η vs.τ) were less precise than that from method 3 (linear plots of 1/ln η vs.τ) because of the curvature of the former plots. The following equations were obtained between η0, and viscosity average molecular weight Mv, respectively
    _??_
    and
    _??_
    Melt viscosity of blends is usually smaller than that of the fractions having the same Mv. Irregular shapes of the extruded filaments appear at constant shear stress τc≈1×106 dyne/cm2 for the fractions irrespective of Mvc for the blends is greater than that of the fractions however. Dependence of Barus effect on molecular weight was well explained with the theory proposed in the preceding paper.
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  • Fukuji Kurihara
    1965 Volume 22 Issue 245 Pages 539-545
    Published: September 25, 1965
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    We have studied the thermal and ultraviolet oxidation of polyoxymethylene (Delrin) film.
    The changes in tensile strength, infrared absorption spectrum, melt flow rate, specific gravity and crystallinity were remarkable by the higher energy irradiation of ultraviolet ray 254mμ, 316mμ and heat treatment at 170°C, while these changes were slow by the lower energy irradiation of ultraviolet ray 354mμ and 380mμ.
    The mechanism of degradation was considered as the random and/or the end scission of polyoxymethylene chain by oxidation.
    We found that higher molecular weight polymer was more stable than lower one in high energy ultraviolet ray irradiation and heat treatment at 170°C and we also observed the increase of crystallinity by oxidation.
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  • Jun Nishino, Kogen O, Makoto Kishida, Takeshi Saburi, Zenshiro Ishikaw ...
    1965 Volume 22 Issue 245 Pages 546-551
    Published: September 25, 1965
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    Vinyl benzoate (I), vinyl α-naphthoate (II), vinyl triphenylacetate (III), vinyl p-chlorobenzoate (IV), vinyl 2, 4-dichlorobenzoate (V), vinyl hexahydrobenzoate (VI), vinyl trimethylacetate (VII), and vinyl dichloroacetate (VIII) were synthesized mainly by means of transesterification of vinyl acetate with the corresponding carboxylic acids.(V) is a new monomer which melts at 38°C and boils at 105-110°C/4mm Hg. It was found that (IV) boils at 62-69°C/5mm Hg, although 115°C/3mm Hg has been reported as a boiling point of the monomer.
    These monomers were polymerized mainly in bulk at 60°C with AIBN as an initiator. While (III) gave no polymer and (II) gave only a small amount of polymer, the other monomers than (II) and (III) were polymerized in high yields. Polymerization rates of (IV), (V), (VI), (VII), and (VIII) were nearly the same one another, but the rate of (I) was considerably lower than those of the others. For the every monomer, molecular weights of obtained polymers increased with increase of conversion, and sometimes insoluble polymers were produced. Some discussions were given for these results.
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  • IV. On the Effect of Organic Sulfur Compounds in Thermal Degradation
    Yukio Mizutani, Hirofumi Ihara, Keiichi Yamamoto, Seishiro Matsuoka
    1965 Volume 22 Issue 245 Pages 552-556
    Published: September 25, 1965
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    The thermal degradation of polypropylene at the presence of organic sulfur compounds was studied. Organic sulfur compounds used were tetramethylthiuram disulfide (TT), tetramethylthiuram monosulfide (TS), dibenzothiazole (DM) and 2-mercaptobenzothiazole (M). These compounds showed the accelerating effect for the thermal degradation of polypropylene, and the order of these effectiveness was as follows: DM>M>TT>TS.
    The activation energy for the scission reaction of polymer chain at the presence of 1% TT by weight was 23.7 kcal/mol.TT showed the stabilizing effect for the oxidation of polypropylene not only before but also after, the degradation and the other sulfur compounds made polypropylene susceptible of oxidation.
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  • IV. The Polymerization Initiated by Organic Peroxides in Dimethylsulfoxide
    Hiroshi Kiuchi, Masamoto Watanabe
    1965 Volume 22 Issue 245 Pages 557-565
    Published: September 25, 1965
    Released on J-STAGE: February 20, 2012
    JOURNAL FREE ACCESS
    Several organic peroxides were used as the initiator in the homogeneous polymerization of acrylonitrile (AN) in dimethylsulfoxide (DMSO), and lauroyl peroxide (LPO) was found to be effective. Lauroyl peroxide-dimethylaniline (DMA) system has been shown to be the most favorable redox initiator in this work. In this case the rate and the degree of polymerization could be represented by the following equations respectively.
    The rate of polymerization:
    _??_
    The degree of polymerization:
    _??_
    where,
    _??_
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