NIPPON GOMU KYOKAISHI
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Volume 85, Issue 11
Displaying 1-4 of 4 articles from this issue
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General Reviews
  • Structural Analysis of Crosslinking Junctions of Vulcanized Natural Rubber by Field Gradient-Fast Magic Angle Spinning Solid-State NMR Spectroscopy
    Seiichi KAWAHARA
    2012 Volume 85 Issue 11 Pages 347-353
    Published: 2012
    Released on J-STAGE: August 02, 2013
    DOIhttps://doi.org/10.2324/gomu.85.347
    JOURNAL FREE ACCESS
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    Field gradient-fast-magic angle spinning (FG-FMAS) probe, developed for solid-state NMR spectroscopy, was applied to investigate crosslinking junctions of vulcanized natural rubber. Resolution of 1H- and 13C-NMR spectra and correlation between 1H and 13C of the vulcanized natural rubber were investigated by one- and two-dimensional measurements. Signals, appearing between 40 and 60 ppm, were well assigned by FG-FMAS solid state NMR spectroscopy; for instance, signal at 40 ppm was assigned to C1 of trans-1,4-isoprene units, signals at 44 ppm was to secondary carbons adjacent to carbons linking to S atom and signals at 58 ppm were to tertiary and quaternary carbons linking to S atoms. Based on the assignments of the signals, origin of outstanding mechanical properties of the vulcanized natural rubber was related to the structure of crosslinking junctions.
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Report
Activity Report
  • Flow Behaviors of Unvulcanized Rubber Compounds to Control the Practical Processability
    —Mainly about the Processability in Extrusion—
    Hitoshi NISHIZAWA
    2012 Volume 85 Issue 11 Pages 361-367
    Published: 2012
    Released on J-STAGE: August 02, 2013
    DOIhttps://doi.org/10.2324/gomu.85.361
    JOURNAL FREE ACCESS
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    Most important way to analyze processability of unvulcanized compounds in practical process is to evaluate the flow behaviors of the rubber compounds, and to estimate the processability indexes, such as viscosity, pressure loss, relaxation coefficient and others. In this report, I would like to describe the flow behaviors in practical extrusion processes and the relations between these flow behaviors and processability indexes. Furthermore, the trouble occurred in extrusion processes and the countermeasures to solve these troubles will be discussed on the standpoint of these processability indexes and other flow characteristics of unvulcanized compounds.
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Technical Note
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