Kobunshi Kagaku
Online ISSN : 1884-8079
Print ISSN : 0023-2556
ISSN-L : 0023-2556
Volume 16, Issue 170
Displaying 1-10 of 10 articles from this issue
  • IV. The Relationship Between Heat-Setting and Swelling
    Motohiro Tsuruta, Akio Koshimo, Takashi Tagawa
    1959 Volume 16 Issue 170 Pages 333-336
    Published: June 25, 1959
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    In succession of the previous reports, we examined the swelling of different heat-set nylon 6 fibres in sulfuric acid solution. These results showed that steam-set fibre had good dyeing property, but was very difficult to swell compared with that with dry-heat-setting and without heat-setting. This tendency was very similar to increase of density described in the first report and it was found that the difficulty of swelling depended rather on crystal region than on amorphous region.
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  • Atsuo Nishioka
    1959 Volume 16 Issue 170 Pages 337-339
    Published: June 25, 1959
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    Experimental relation between radiation does and melt viscosity of gamma-irradiated polytetrafluoroethylene is satisfactorily explained by the well known relation between melt viscosity and weight average molecular weight, combined with charlesby's degradation theory.
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  • II. Influence of the Film-forming Conditions and Polymerization Type on the Swelling
    Saburo Imoto, Junji Ukida
    1959 Volume 16 Issue 170 Pages 340-343
    Published: June 25, 1959
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    The films of PVA prepared under the various polymerization conditions were formed at room temperature (about 20°C) and 50°C, and heat-treated at 150°C for 30 minutes, then swelled in water at 30°C after treating in the aqueous periodate solution. The results obtained are as follows: 1) Since the degrees of swelling vary with the film-forming conditions, it seems that the differences in fine texture exist. 2) In the heat-treated films, the degree of swelling of PVA prepared by methanol solution polymerization is smaller than that of PVA obtained from bulk polymerization. 3) When a large amount of benzoyl peroxide is used as the initiator of polymerization, the degree of swelling of PVA obtained is greater than that of PVA polymerized with AZN.
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  • Makoto Shiraishi, Masakazu Matumoto
    1959 Volume 16 Issue 170 Pages 344-348
    Published: June 25, 1959
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    In the previous report we found that oxidized PVA degraded through a reverse aldol reaction when it was treated by alkaline solution, but that only one third of the carbonyl groups of the PVA contributed to the degradation. The reason became clear in the present study. The carbonyl groups of the PVA undergo keto-enol tautomerism depending on pH and temperature and may assume acidic behavior in some conditions. When the PVA is treated in strong acidic solution, all the carbonyl groups take keto-form and contoribute perfectly to the degradation reaction.
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  • XIII. Polymerization in iso-Propyl Chloride and Chain Transfer of Polymer
    Taizo Uno, Keinosuke Yoshida
    1959 Volume 16 Issue 170 Pages 349-352
    Published: June 25, 1959
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    The polymerization of vinyl chloride in iso-propyl chloride was studied at 50°C and 60°C with α, α′-azobisisobutylonitril used as initiator. The rate of polymerization is proportional to the [I] 0.5 and [M] 1.1. The chain transfer constant of the solvent obtained from the plot of 1/P-Rp/AM2 against S/M is 7.0×10-4 (50°C) and 8.2×10-4 (60°C). If iso-propyl chloride is thought as a model of polyvinyl chloride, the chain transfer of PVC nearly equalled the monomer in largeness. The calculated branch content per polymer molecule are about 10 at 94% conversion. This content is similer to the value, 10-20, which Bier, Krämer and Cotoman obtained by measuring the infrared absorption.
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  • V. Effect of Thickness of Samples on the Oxidation Rate of Polyethylene
    Syunzi Kawamatu
    1959 Volume 16 Issue 170 Pages 353-358
    Published: June 25, 1959
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    The rates of oxidation of high polymers are influenced by the thickness of samples. Their reaction rates depend upon principally their oxidizability and oxygen diffusibility into samples. The author measured the oxidation rates of polyethylene at 120°C and above, varing the thickness between 0.05 mm and 3.0 mm. On oxidation existed short induction periods, and after that periods, reaction rates increased rapidly, via maximum, decreased also rapidly. Activation energy calculated from maximum rates was 33 kcal/mol, if the samples were enough slight. When the samples were sufficiently thick, activation energy was 17 kcal/mol. And the diffusion equation on supposing that oxidation rates are proportional to the oxygen content, was solved and compared with experimental results.
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  • VI. Oxidation of Polyethylene by the γ-Ray Irradiation
    Syunzi Kawamatu, Akira Arai
    1959 Volume 16 Issue 170 Pages 358-362
    Published: June 25, 1959
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    It is well known that polyethylene is oxidized in air by γ-ray irradiation at the room temperature. But its oxidation mechanisms have not been elucidated in detail. Therefore, we measured the oxygen absorption with time under the various γ-ray intensities, and studied its oxidation mechanisms. The rates of oxidation increased autocatalitically with its oxygen absorption and then reached maximum values. It is concluded that γ-ray oxidations include apparent radical chain reactions. The oxygen absorption was more effective at weaker intensities than stronger intensities. Moreover, the flow points of the irradiated samples have not practically increased under the irradiation of more than 20 Mrep, and cross-links have not been almost produced.
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  • Ichiro Sakurada, Akio Nakajima, Hideto Sotobayasi
    1959 Volume 16 Issue 170 Pages 363-368
    Published: June 25, 1959
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    The copolyelectrolytes were prepared by the saponification of the copolymer composed of vinylacetate and methylacrylate. For the purpose of obtaining the samples homogeneous both in the composition and in the degree of polymerization, copolymerization was carried out at low conversion and especially from the monomer mixtures containing small amount of methylacrylate. The copolymer acids, obtained by the saponification of the copolyesters, were then converted into the corresponding sodium salts. Viscosity, osmotic pressure, electroconductivity and pH of these sodium salts were measured in aqueous solutions. The spatial configurations of the polymer chain and the number of the effective charge on the polymer were discussed as the functions of the composition of the copolymers and of the concentration of the solutions.
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  • VII. On the Flow Property of Heated Resin
    Riyoji Yokoyama
    1959 Volume 16 Issue 170 Pages 369-375
    Published: June 25, 1959
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    Mixtures of phenol novolac and hexamine were heated and their flow property and solubility in ethanol were measured. The following facts were found in this experiment: The heated resin had some Newtonian flow under the condition of high temperature and high pressure, even when some insoluble resin was formed in it, therefore its absolute viscosity was able to be measured. The viscosity of the heated resin was almost constant before an insoluble resin was formed in it, but the value of viscosity increased as the amount of insoluble resin increased. The soluble resin contained in the heated resin had almost the same flow property at any heating condition, and the value of flow was almost equal to phenol novolac which was not heated, but the insoluble resin in it did not flow, being independent of any heating condition, even at high temperature and high pressure.
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  • VII. Association and Precipitation of Polyvinylalcohol in Solution
    Ryunosuke Naito
    1959 Volume 16 Issue 170 Pages 376-380
    Published: June 25, 1959
    Released on J-STAGE: October 14, 2010
    JOURNAL FREE ACCESS
    Precipitation points were measured at constant polymer concentration for the dilute polyvinylalcohol solutions, where water and dimethylsulfoxide were used as solvents and acetone, methylalcohol, ethylalcohol and n-propylalcohol were used as precipitants. A plot of the precipitation point γ′(volume fraction of precipitant added, that produces the first haze) vs. 1/[η] showed deviations at high molecular weight region from a linear relationship in all systems measured. These anomalies make the fractionation of polyvinylalcohol impossible at high molecular weight region. Then, the intrinsic viscosity, [η], of polyvinylalcohol in water-ethylalcohol mixed solvent, where the polyvinylalcohol molecules associate stably, was measured and compared with the intrinsic viscosity, [η]0 in water at 30°[η]/[η]0, which seems to be the measure of the degree of association, increased with the molecular weight at low molecular weight region but decreased on the contrary at high molecular weight region. Namely, there existed the molecular weight in which the degree of association became maximum. Accordingly, it was concluded that the anomalies of the precipitation point were caused by the effect of the association of polyvinylalcohol.
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