NIPPON GOMU KYOKAISHI
Print ISSN : 0029-022X
Volume 82, Issue 3
Displaying 1-9 of 9 articles from this issue
Regular Papers
  • Tetsuo YAMAGUCHI, Satoshi OHMATA, Masao DOI
    2009 Volume 82 Issue 3 Pages 93-97
    Published: 2009
    Released on J-STAGE: April 05, 2010
    JOURNAL FREE ACCESS
    In this paper, we report our studies on sliding friction of an adhesive gel-sheet. Due to the stickiness of the gel, it never slips at the contact area but can make relative motions via the propagation of detachment waves. We found that the patterns of the detachment waves transform from regular stripe-like at larger pull velocities to irregular bubble-like at smaller pull velocities. Furthermore, from photo-elasticity experiments to visualize the stress state of the contact area, we discovered that the irregular bubble-like patterns are closely related to inhomogeneity in stress fields.
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  • Hiroaki KONDO, Yoshito OHTAKE
    2009 Volume 82 Issue 3 Pages 98-104
    Published: 2009
    Released on J-STAGE: April 05, 2010
    JOURNAL FREE ACCESS
    The composite of natural rubber mechanically mixed with fullerol using the open roll mill contained large agglomerate of fullerol in the fracture surface of tensile test piece, and no effect in reinforcement was observed. On the other hand, the composite prepared by wet-process method in which fullerol solution mixed with the NR latex contained well dispersed fullerol, and showed increased modulus and tensile properties at break compared with fullerol free. Fullerol dispersed in polymer inhibited decrease of tensile strength after aging and production of carbonyl group by oxidative degradation.
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  • Hiroshi WADA, Hiroki FUKUDA, Shigeaki YONEMORI
    2009 Volume 82 Issue 3 Pages 105-111
    Published: 2009
    Released on J-STAGE: April 05, 2010
    JOURNAL FREE ACCESS
    Three kinds of aromatic diamines (DETDA,tBu-TDA,CPA) as chain extenders and novel polypropylene glycols (designated PPGs) were used for polyurethaneurea reaction injection molding (designated RIM) elastomer. The morphology and physical properties of each polyurethaneurea RIM elastomer were studied by using TEM, SEM, dynamic mechanical thermal analysis. The polyurethaneurea RIM elastomer by using CPA as a chain extender showed superior heat sag data as compared with DETDA and tBu-TDA .
    As novel PPGs contain an extremely smaller amount of by-products (monools), the actual functionalities of novel PPGs are higher than that of conventional ones. Polyurethaneurea RIM elastomers by using novel PPGs showed good physical properties and productivity. Especially, heat resistance property from 150 °C to 230 °C was improved by the increase of crosslinking density of polyurethaneurea RIM elastomers. It was also revealed that the increase in molecular weight of novel PPGs and a rise of the post cure temperature accelerate the phase separation of polyurethaneurea RIM elastomers. The transformation of morphology was observed.
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Technical Papers
  • Eiichi TAKATORI, Takatoshi SHIMURA
    2009 Volume 82 Issue 3 Pages 112-116
    Published: 2009
    Released on J-STAGE: April 05, 2010
    JOURNAL FREE ACCESS
    Load of the extrusion oscillates during the extrusion of high density polyethylene melt. We studied this phenomenon through the rheometry. It was concluded that in some cases this oscillation phenomenon is related with melt steady state compliance Je0 of high density polyethylene melt.
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  • Nobuyuki ITO, Tsuneo HIRONAKA, Hideyoshi NAKAMURA, Tamotsu SATO
    2009 Volume 82 Issue 3 Pages 117-123
    Published: 2009
    Released on J-STAGE: April 05, 2010
    JOURNAL FREE ACCESS
    The cure bonding between chlorosulfonyl polyethylene (CSM) and fluoroplastic (terpolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride) has been developed. In the case of cure bonding of chlorinated polyethylene by trithiocyanuric acid (TCA), the difference in accelerator, such as tetra-n-butylphosphonium benzotriazolate and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) salts, did not influence on cure bonding, however, the presence of water was found important to get high bonding strength. Thus the addition of sodium acetate trihydrate that releases water of crystallization during cure bonding significantly improved the bonding strength.
    For compounds of conventional CSM having 1 wt% of sulfur in the chlorosulfonyl group as a cross-linking site with sodium acetate trihydrate and TCA, their viscosity became too high to be mill mixed and molded, when an accelerator DBU salt such as formate or benzoate having a melting point below milling temperature, 130 °C, was used. DBU salts having melting points above milling temperature, such as trimellitate and pyromellitate, showed poor cure bonding.
    A compound of CSM having 0.3 wt% of sulfur in the chlorosulfonyl group with TCA, DBU phenolate and sodium acetate trihydrate was able to be mill mixed, molded and cure bonded. The vulcanizate satisfied the specifications of automotive fuel hoses.
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General Reviews
  • Kazuya NAGATA, Shigeki HIKASA
    2009 Volume 82 Issue 3 Pages 124-129
    Published: 2009
    Released on J-STAGE: April 05, 2010
    JOURNAL FREE ACCESS
    Many researchers reported that the impact strength and modulus of composites were depended markedly on the dispersion states of elastomer and filler particles in polypropylene (PP). The effects of dispersion states of blended elastomer (SEBS) particles and fine CaCO3 particles on the impact strength of the composites are systematically reviewed in this paper. Furthermore, the mechanism of impact strength improvement of the composites is discussed based on the results of optical microscope observation of fractured specimens.
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  • Sadaki MORI
    2009 Volume 82 Issue 3 Pages 130-134
    Published: 2009
    Released on J-STAGE: April 05, 2010
    JOURNAL FREE ACCESS
    Materials used in shoes have been widely developed according to the application conditions. Especially shoe sole is an important part to produce high-performance and prevent injuries. On the other hand, not only the development of new sole material but also adhesive technology and molding process of each individual part are so important in the shoes designing process. A shoe sole is consisted of many kinds of materials, for example, high abrasion rubber, EVA sponge and resin, etc. These parts are adhered with solvent adhesion manually. Therefore sole fabrication processes take much time and the qualities, such as adhesive strength and sole durability, are unstable.
    In this few years, adhesive and molding methods have been developed with considering environmental issue. In this paper, the current technological aspects, material development, adhesive, molding technology and environmental issue are presented.
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Advanced Course on Rubber Science and Technology
  • Shigeru YAMAGO, Yasuyuki NAKAMURA
    2009 Volume 82 Issue 3 Pages 135-140
    Published: 2009
    Released on J-STAGE: April 05, 2010
    JOURNAL FREE ACCESS
    Living radical polymerization (LRP) has been becoming an indispensable method for the synthesis of functional polymer materials, because this method possesses attractive features of both radical and living polymerizations. This four-series article describes the methods to carry out LRP and their uses for material synthesis. We shall mainly focused on nitroxide-mediated LRP (NMP), atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer polymerization (RAFT), organotellurium-, stibine-, and bismuthine-mediated LRP (TERP, SBRP, and BIRP, respectively), and cobalt-mediated LRP (CORP). This first article mainly focuses on methods and mechanisms of NMP and ATRP, in which the persistent radical effect plays an important role in the polymerization mechanism.
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Technical Note
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