KOBUNSHI RONBUNSHU
Online ISSN : 1881-5685
Print ISSN : 0386-2186
ISSN-L : 0386-2186
Volume 58, Issue 9
Displaying 1-9 of 9 articles from this issue
  • Jianhui QIU, Makoto KAWAGOE, Wataru MIZUNO, Mikio MORITA, Tetsuo KUMAZ ...
    2001 Volume 58 Issue 9 Pages 427-434
    Published: September 25, 2001
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    The relationship between of the microstructure and the mechanical properties of Polypropylene (PP) under quasi-static and dynamic tensile loading has been examined with reference to the combined effects of rolling and blending with Liquid Crystalline Polyester (LCP). The rolling process has modified the microstructure and thus has improved the quality of material. Tension test showed that by adding LCP the elongation decreases, but the tensile strength is improved. After experiencing a rolling process, the blended material shows high ductility and higher strength than PP. The fatigue failure resistance was enhanced by adding LCP not only at room temperature but at lower temperature (-10°C), and the failure tended to be more brittle. When they were rolled, the ductile properties of both materials were increased, and the samples did not rupture under any stress amplitude. Moreover, the fatigue resistance of the blended sample was enhanced beyond that of neat PP. The above results suggest that the combination of the rolling and the blending processes are an effective procedure to improve the mechanical properties of polymeric materials.
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  • Kazunori Suzuki, Kunio MORI, Hidetoshi HIRAHARA, Noriyuki YOSHIMOTO
    2001 Volume 58 Issue 9 Pages 435-441
    Published: September 25, 2001
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    Films of 6-dibutylamino-1, 3, 5-triazine-2, 4-dithiol (DB) were formed on the stainless steel substrates by the conventional vacuum deposition method. The metal substrates were baked and unbaked under ultra high vacuum condition to remove adsorbed water. Adsorption and desorption probability of DB molecules, and molecular structures of DB films on stainless steel and Fe substrates were investigated by ellipsometry, XPS and AFM. The results showed that the adsorption probability of DB molecules on a baked substrate was smaller than that on an unbaked substrate. The desorption of DB molecules from the baked substrate did not occur easily. XPS data showed that DB molecules easily formed disulfide bonds on the unbaked substrate surface. It is suggested that adsorbed water on the substrates caused polymerization in the DB films. The adsorption probability of DB molecules on the stainless steel substrate was small and the desorption of DB did not occur easily compared with the Fe substrate. It is assumed that DB was difficult to be polymerized on the stainless steel substrate.
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  • Toshio OGAWA, Hideki JINNAI, Satoshi OSAWA
    2001 Volume 58 Issue 9 Pages 442-447
    Published: September 25, 2001
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    The light deterioration of oriental lacquer film is suppressed when a special fluorescent lamp for museums is used instead of a conventional lamp. However, the light deterioration was anticipated to occur from the past study even if such special lamps were used, when the intensity of luminance was increased. In this study, the wavelength dependence of light deterioration on the film was examined using several fluorescent lamps radiating light of different wavelengths. The gloss of the film decreased a little in the radiation of the visible rays, though the wavelength dependence was not confirmed. The effect on the color difference was not clear. On the other hand, the surface oxidation advanced by the radiation of visible ray, though the oxidation was not so much as compared with that of ultraviolet rays. The content of double bonding on the film surface also decreased by irradiating the visible light having short wavelengths. Therefore, it is sure that the chemical change steadily progresses due to the visible rays, though the apparent change is small in an exposure test for one year. Thus, we conclude that the effect due to visible light was considerably smaller than that due to the ultraviolet ray.
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  • Kazuki HASHIMOTO, Kyoji SUZUKI
    2001 Volume 58 Issue 9 Pages 448-452
    Published: September 25, 2001
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    In order to synthesize cationic water-soluble graft terpolymers, we copolymerized acrylamide (AM) and 2- (dimethylamino) ethyl methacrylate (DMAEMA) on cyclodextrin (CD) or dextrin (D). Grafting and intrinsic viscosity of synthesized graft terpolymers decreased with increasing DMAEMA feed. Moreover, D-graft- (AM-DMAEMA) graft terpolymers showed higher intrinsic viscosity than CD-graft- (AM-DMAEMA) graft terpolymers. The FT-IR spectra proposed that graft terpolymerization was initiated by abstraction of a hydrogen atom at C1 carbon atom in the glucopyranose ring. These cationic graft terpolymers had superior flocculation effect compared with AMDMAEMA copolymer contained as the branches.
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  • Hitoshi INATA, Kunihiko TAKEDA
    2001 Volume 58 Issue 9 Pages 453-461
    Published: September 25, 2001
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    In the tetrabromobisphenol A-bis (2, 3-dibromopropyl ether) (TBA-DB) and polypropylenes (PP) system, the blooming was suppressed by the addition of ethylene/vinyl acetate copolymer (EVA) to PP, and the relation between the EVA content necessary for the suppression of blooming and the TBA-DB content was determined. The appropriate temperature of blooming acceleration test for injection molding was not generally high but moderate around 50°C. A general acceleration test could be applied to the phenomenon where the reaction rate obeys the Arrhenius equation and was accelerated by elevating temperature. In the case of injection moldings a similar behavior to that of a solution where a solute dissolves in a solvent was observed in their blooming phenomenon. Namely, at high temperatures, the solubility is high and the precipitating (blooming) material is scarce (or absent). On the other hand, at low temperatures, although the precipitating material is abundant, the transportation rate is low and hence the blooming does not occur. The most appropriate temperature was determined to be around 50°C on a balance of the above-mentioned compensating effects.
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  • Hitoshi INATA, Koji OHGI, Nobuhiko HIGASHI, Kunihiko TAKEDA
    2001 Volume 58 Issue 9 Pages 462-471
    Published: September 25, 2001
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    The EVA content necessary to suppress the blooming in sheetings was determined. The content was higher than that in the case of injection moldings, and the appropriate blooming acceleration temperature was around 70°C being higher than that in the case of injection moldings. This is assumed to be because the amorphous region of PP in sheetings which can dissolve TBA-DB is less than that in injection moldings and because there exist skin layers where the transportation rate of additives is low in injection moldings. When a stimulation is applied to a part of surface of injection molding or sheeting by, for example, sucking operation and handling just after processing, a blooming generates at the part, and the necessary EVA content was determined to suppress it. TBA-DB has crystalline and amorphous forms, and the crystalline substance was observed as blooms while the transparent amorphous substance was not observed. Whether the crystalline substance is formed in the processed article or not unitarily determines the generation of blooming. When a stimulation was applied to the surface of a processed article at temperatures above the softening temperature of the amorphous substance (40°C), crystallization nuclei generated on it. By aging the processed article at temperatures above 40°C, the nuclei absorbed the amorphous substance, grew and became to be observed as blooms.
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  • Toshio AZECHI, Masanori HANSAKA, Minoru SUZUKI, Naoto MIHUNE, Riichiro ...
    2001 Volume 58 Issue 9 Pages 472-479
    Published: September 25, 2001
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    To economize on the manpower needed for train maintenance, evaluation of the degradation properties of the cone-type axle spring rubber is strongly demanded. It is a very important material to control train vibration, and whether it can be used for a long period of time must be examined. As a result of experiments on degradation properties of the axle spring rubber, the following properties have been revealed. As the initial stage of its usage, the inner layer of axle spring rubber is degraded more in molecular chains than in the middle and outer layers because the vibration load is applied directly to the soft inner layer. As the inner layer is degraded, however, it loses the ability to absorb vibration, and the vibration load is transferred to the middle layer. Consequently, the degradation is the greatest in the middle layer of the three layers after it is used for several years. Moreover, the degradation of the axle spring rubber can mainly be attributed to complex factors, such as environmental conditions, heat generated when the rubber absorbs vibration energy and fatigue due to vibrating stress.
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  • Effect of Blending Method on Impact Resistance
    Hideaki IMANISHI, Tomohiro YAMAGUCHI, Atsushi YASUDA
    2001 Volume 58 Issue 9 Pages 480-485
    Published: September 25, 2001
    Released on J-STAGE: March 15, 2010
    JOURNAL FREE ACCESS
    The impact resistant property of polypropylene (PP) could be improved by the addition offinely powdered calcium carbonate (CC), and the factors for the improvement were investigated including kind of PP and CC, and the blending process with a heat twin roller. PP with high melt viscosity showed excellent effects, and CC of 0.1-0.3 μm in diameter treated with fatty acid salts showed excellent effects. The blending process with a heat twin roller was also a significant factor. An addition of large amounts of CC to PP induced high melt viscosity due to breaking of second coaggulation of CC. These results suggest that the sufficient dispersion of powdery CC in the PP matrix was significant for the improvement of the impact resistant properties. However, SEM observation failed to relate the sufficient dispersion of powdery CC in the PP matrix with remarkable improvement of the impact resistant property.
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  • Hiromasa ADACHI, Teruo HASEGAWA
    2001 Volume 58 Issue 9 Pages 486-488
    Published: September 25, 2001
    Released on J-STAGE: July 27, 2010
    JOURNAL FREE ACCESS
    The static modulus and the dynamic storage modulus were investigated for some open-celled polyethylene foams by static compression tests and dynamic viscoelastic measurements in compression mode. The static modulus has been found to correlate with the dynamic storage modulus positively, especially to relate linearly with the dynamic storage modulus at 50% shrinkage. The dynamic storage modulus is considered to be larger than the static modulus because of the creep deformation due to buckling. The relation given by Iizuka et al. was found to be in reasonable agreement with the experimental data of the static compression modulus in the case that porosity was large and that θ was 15°-24°.
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