NIPPON GOMU KYOKAISHI
Print ISSN : 0029-022X
Volume 93 , Issue 5
Showing 1-8 articles out of 8 articles from the selected issue
General Reviews
  • Rikka SAKAMOTO
    2020 Volume 93 Issue 5 Pages 147-151
    Published: 2020
    Released: July 15, 2020
    JOURNALS RESTRICTED ACCESS

    The 2030 Agenda for Sustainable Development is a plan of action for people, planet and prosperity. The 17 Sustainable Development Goals and 169 targets demonstrate the scale and ambition of this new universal Agenda. They seek to build on the MDGs and complete what they did not achieve.

    The Government of Japan established a new Cabinet body headed by the Prime Minister and composed of all ministers. The SDGs Promotion Headquarters was established to lead the comprehensive implementation of SDGs-related measures as a control tower.

    The Kansai SDGs Platform was established in December of 2017 as a body designed to bring together actors from a wide spectrum in Kansai.

    The primary aim of the Kansai SDGs Platform is to widely publicize the importance of the SDGs in Kansai and to increase awareness and understanding of this topic.

    The Kansai Bureau of Economy, Trade and Industry (METI-KANSAI) is committed to contributing to the development of the local economy by mobilizing the experience, expertise and various policies. METI-KANSAI actively supports the creation and worldwide dissemination by Kansai businesses of a “Japanese SDGs model", towards the realization of a sustainable economy and to aid in preparations for the upcoming Expo 2025 Osaka, Kansai.

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  • Yuichi AOYAGI
    2020 Volume 93 Issue 5 Pages 152-158
    Published: 2020
    Released: July 15, 2020
    JOURNALS RESTRICTED ACCESS

    In practice, sealing materials are always used under deformation and are subject to various aging processes as a function of ambient factors for example, temperature and oxygen, frequently manifested in stress relaxation impacted critically with respect to the long-term functioning of the seal. This study thus aims to contribute to a detailed understanding of the specific aging mechanism of stress relaxation in the case of EPDM elastomers. To this end, the influence of material and ambient parameters on irreversible changes in the crosslinking and chemical structures of the polymer matrix under mechanical load was extensively examined. Attainment of the targeted objective of this study involved further development and optimization of innovative characterization methods like low-field time-domain NMR spectroscopy with inverse Laplace transformation (ILT) and chemiluminescence under deformation. The NMR methods and the ILT analysis methods further developed here were used to describe as precisely as possible the structural changes occurring in the network and with respect to chain mobility. With the help of this method, it was possible to quantify structural changes like crosslinking, the share of free chain ends and free chain fragments formed during the aging process. All the aforementioned material parameters were found to have a significant impact on the aging-related change in stress relaxation at constant deformation. The rate of thermal oxidation under deformation was also shown to be greater than in a non-deformed state. The new characterization methods allow for a much more precise description, and thus a markedly better understanding, of the stress relaxation mechanism among elastomers.

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Advanced Course on Rubber Science and Technology
  • Yukio NAKAJIMA
    2020 Volume 93 Issue 5 Pages 159-165
    Published: 2020
    Released: July 15, 2020
    JOURNALS RESTRICTED ACCESS

    Tire pattern is related to various tire performances. The first step for the design of tire pattern is to design pattern rigidity and then tune the pattern to satisfy the required performances by using the simple design tool based on the analytical model, numerical simulation and designer's experience. The pattern design for pattern rigidity, tire noise, hydroplaning, maneuverability and wear will be discussed in this paper.

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  • 3. Structure of Silane Coupling Agent at the Interface in Composite
    Yoshinobu NAKAMURA, Tomoyasu HIRAI, Syuji FUJII
    2020 Volume 93 Issue 5 Pages 166-169
    Published: 2020
    Released: July 15, 2020
    JOURNALS RESTRICTED ACCESS

    The network and the hairy structures expected to be formed on the filler surface by the treatment with trialkoxy and dialkoxy types of silane coupling agent (SCA) having mercapto group, respectively. The stress-strain curve of the filled isoprene rubber (IR) composite was investigated. The 300% modulus was higher in the dialkoxy than in the trialkoxy system. The entanglement of SCA and IR chains tends to occur in the dialkoxy system. The loose network structure is formed by the mixture of dialkoxy and smaller amount of trialkoxy types. The loose network was more effective to improve the 300% modulus. The interpenetrating polymer networks (IPN) by the SCA and IR chains expected to be formed at the interface. In order to reinforce the IR composite with calcium carbonate particles, the surface treatment with a mixture of amino- and mercapto-functional SCAs was useful. Interaction between the amino group and the calcium carbonate surface, covalent bonding between the mercapto group and the IR, and dense network formation of trialkoxy SCAs were important for improving the mechanical properties.

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  • Chapter3 : Mixing and Separation of Materials
    Masao DOI
    2020 Volume 93 Issue 5 Pages 170-175
    Published: 2020
    Released: July 15, 2020
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    Mixing and separation are fundamental processes in material making. Here, thermodynamic bases of mixing and separation are discussed for solutions (a mixture of solute and solvent) and gels (a mixture of polymer network and solvent). It is shown that all equilibrium properties of these materials are calculable from the free energy function, written as a function of temperature and concentration (for solutions) or temperature and stretch ratio (for gels).

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  • 1. Chemistry of Sulfur Chain and Sulfur-Containing Silane Coupling Agents
    Toshikazu TAKATA
    2020 Volume 93 Issue 5 Pages 176-182
    Published: 2020
    Released: July 15, 2020
    JOURNALS RESTRICTED ACCESS

    Chemistries of sulfur and sulfur-containing silane coupling agent as important materials in rubber manufacture are discussed directed toward the understanding of fundamental property of sulfur chains. In relation to polymeric sulfur insoluble in carbon disulfide which is used as a key material for crosslinking of tire rubber, basic property of sulfur and chemistry of sulfur chain involving more than two sulfur atoms are introduced, where instability of oligosulfide is emphasized under both radical and ionic reactions. Chemistry of oligosulfide linkage of silane coupling agents used for automobile tires reinforced by silica is effectively contributed to the development of the new manufacturing method of the silane coupling agent at 2000.

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Introduction to Rubber Science and Technology
Technical Note
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