NIPPON GOMU KYOKAISHI
Print ISSN : 0029-022X
Volume 57, Issue 12
Displaying 1-8 of 8 articles from this issue
  • R. C. Hirst, [in Japanese]
    1984 Volume 57 Issue 12 Pages 785-795
    Published: 1984
    Released on J-STAGE: April 16, 2008
    JOURNAL FREE ACCESS
    Download PDF (827K)
  • [in Japanese], [in Japanese]
    1984 Volume 57 Issue 12 Pages 795
    Published: 1984
    Released on J-STAGE: April 16, 2008
    JOURNAL FREE ACCESS
    Download PDF (67K)
  • G. R. Hamed, T. Donaitelli, [in Japanese]
    1984 Volume 57 Issue 12 Pages 796-804
    Published: 1984
    Released on J-STAGE: April 16, 2008
    JOURNAL FREE ACCESS
    Download PDF (783K)
  • Yoshiro NAKAMURA, Kunio MORI, Makiko TSUNEISHI, Kosaku TAMURA, Yoshiko ...
    1984 Volume 57 Issue 12 Pages 805-810
    Published: 1984
    Released on J-STAGE: April 16, 2008
    JOURNAL FREE ACCESS
    6-R-1, 3, 5-triazine-2, 4-bis(benzothiazolyl disulfide) (I) and 4, 6-bis-R-1, 3, 5-triazine-2-benzothiazolyl disulfide (II) [R: -NHC6H4NHC6H4, -N(i-C3H7)C6H4NHC6H5.] have been found to react as an extraction-resistant antioxidant with an accelerating activity for vulcanization of IR, SBR, and NBR to give an improved vulcanizates with an ageing resistant property even after solvent extraction. The accelerating activity was much more improved by using coagent such as TMTM, TMTD. A bound per cent was 20-36 and 75-99% for IR and NBR, respectively.
    Download PDF (386K)
  • Shujiro SHIGA, Yufu SATO
    1984 Volume 57 Issue 12 Pages 811-817
    Published: 1984
    Released on J-STAGE: April 16, 2008
    JOURNAL FREE ACCESS
    Gamma ray-irradiated EPM's, as model polymers of branched EPDM, are investigated on the relation g'=gb, where g' is the ratio of intrinsic viscosities of the branched and linear molecules of equal molecular weight (MW), [η]br/[η]1, and g the ratio of mean-square radii of gyration of the two, <s2>br/<s2>1. The MW distributions measured by GPC-LALLS coincide well with theoretical curves of tetrafunctionally and statistically branched polymers obtained by the ideal degradation and crosslinking of the raw EPM, which assumed to have the most probable MW distribution, and the b-value is then determined to be 1.1.
    EPDM samples, polymerized with a soluble vanadium compound-alkyl aluminum halide type catalyst in a contineous well-stirred pilot-reactor, are characterized on number of branching points per molecule for various MW by using the b-value. The higher the MW, the distance between neighboring crosslinking points seems to become the narrower. The reason is discussed. The unsaturated bond by dicyclopentadiene of the rubber crosslinks easier in the manufacturing process than that by 5-ethylidene-2-norbornene. The largest high-MW portion and the broadest MW distribution are observed in the EPDM with the maximum dicyclopentadiene content.
    Download PDF (592K)
  • Kunio MORI, Makiko TSUNEISHI, Yoshiro NAKAMURA
    1984 Volume 57 Issue 12 Pages 818-828
    Published: 1984
    Released on J-STAGE: April 16, 2008
    JOURNAL FREE ACCESS
    Evaluation of 2-antioxidant group-4, 6-bis(4-morphorinyl trithio)1, 3, 5-triazine(Vulcanizing antioxidant) on unsaturated rubbers such as IR, BR, SBR, and EPDM has been investigated for vulcanizing properties, the % bound of antioxidant groups, the structure of crosslinkage, and the heat resistance of vulcanizates. Vulcanizing antioxidants acted as a vulcanizing agent in the copresence of ZnO and stearic acid. The vulcanizing reactivity was influenced by the kind of rubbers. The copresence of accelerators such as TMTM, CBS, and MBTS was very effective to increase vulcanizating rates and crosslinking degree. The % bound of antioxidant groups was large for BR and SBR, but small for IR and EPDM. Both CBS and MBTS were effective accelerators to increase the % bound, and TMTM was effective one to increase the monosulfide crosslinkage contents. The combination of vulcanizing antioxidant and TMTM was found to give the vulcanizates which are effective under the conditons that contact with high temperature and solvents, in which commercial antioxidants commonly are removed, as they have both excellent % bound and monosulfide crosslinkage contents.
    Download PDF (569K)
  • Toru NOGUCHI, Michio ASHIDA, Satoshi MASHIMO
    1984 Volume 57 Issue 12 Pages 829-837
    Published: 1984
    Released on J-STAGE: April 16, 2008
    JOURNAL FREE ACCESS
    The mechanical properties and swelling anisotropy of short fiber-elastomer composites were examined using two kinds of fibers; PET and carbon fiber, and matrix elastomers; EPDM, urethan rubber (UR), and CR. Those properties were affected by orientation of fibers, adhesion between fibers and matrix, and type of matrix.
    Although PET fibers retained their original length after mixing, carbon fibers were broken to pieces of 150μm in length during mixing. Those fibers oriented unidirectionally in matrix rubber for the composites containing less than 10vol.% fibers. For non-polar EPDM with RFL-untreated PET fibers, the yield stress was the half of that of polar CR. In the case of RFL-treated fibers, the tensile stress of the composite increased almost linearlly till fracture with increasing strain. When the tensile stress of untreated PET-UR composite increased gradually, avoid was formed at the end of fiber and elongated longer with increasing strain. The tensile stress of PET-UR composite was increased a little by isocyanate treatment on PET surface. In the transeverse direction of fibers, the tensile stress of these cmposites with untreated PET gave the same values as that of matrix after breaking the adhesion between fibers and matrix. For carbon fiber-elastomer composite, the tensile stress and young's modulus in the longitudinal direction of fibers were much smaller than that of the composites with PET fibers. In the transeverse direction, the composite was not reinforced by carbon fibers because the interaction between carbon fibers and matrix were very weak.
    Download PDF (998K)
  • 1984 Volume 57 Issue 12 Pages 846-847
    Published: 1984
    Released on J-STAGE: April 16, 2008
    JOURNAL RESTRICTED ACCESS
    Download PDF (232K)
feedback
Top