NIPPON GOMU KYOKAISHI
Print ISSN : 0029-022X
Search
Advanced search
OR
Browse
Search
Volume 42, Issue 12
Displaying 1-8 of 8 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
  • PROPERTIES OF CROSSLINKED RUBBER
    (II) EFFECTS OF DEGREE OF CROSSLINKING IN POLYBUTADIENE AND EP RUBBERS
    K. Nakashima, S. Yamashita
    1969 Volume 42 Issue 12 Pages 1009-1015
    Published: 1969
    Released on J-STAGE: April 16, 2008
    DOIhttps://doi.org/10.2324/gomu.42.1009
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Dynamic mechanical properties of polybutadiene (BR) and ethylenepropylene rubber with a wide range of degree of crosslinking were studied. Dynamic shear modulus (G′) of BR increases with increasing the degree of crosslinking, while G′ of EP rubber decreases. This result of EP rubber is observed up to 70°C and frequency of over 3 cps.
    Since it is believed that the decrease of G′ can be attributed to the effect of chain entanglement, the molecular weight between entanglements (Me) was calculated from the G′ on the base′s of theories of rubber elasticity.
    From this calculation, EP rubber shows a large Me value. This is probably due to a small amount of aggregation based on the blockness in a long -(CH2)n- sequence.
    This result may suggest that the measurment of dynamic modulus as a function of degree of crosslinking is a good method for evaluating the blockness.
    In addition, it is found that experimental values of log G′/G60 (static modulus) is propotional to the average molecular weight between crosslinks in the network.
    View full abstract
    Download PDF (587K)
  • EPDM AND EPM IN THE PRESENCE RGANIC COMPOUNDS
    (I) THE EFFECTS OF VARIOUS VINYL COMPOUNDS ON THE PEROXIDE CURE OF EPDM AND EPM
    M. Imoto, Y. Minoura, K. Goto, H. Harada, K. Nishihira, H. Fujita, K. ...
    1969 Volume 42 Issue 12 Pages 1016-1029
    Published: 1969
    Released on J-STAGE: April 16, 2008
    DOIhttps://doi.org/10.2324/gomu.42.1016
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    On the peroxide cure of EPDM and EPM, the effects of various vinyl compounds having different functionalities, chain length between vinyl groups, and electron density of c=c double bond were studied.
    It was found that polyfunctional vinyl compounds (ethylene-dimethacrylate, trimethylolpropantrim-ethacrylate, N, N′-m-phenylenebismaleimide, N, N′-methylenebisacrylamide were more effective than monofunctional vinyl compounds (laurylmethacryrate, maleimide, phenylmaleimide, acrylamide).
    The dimethacrylates having the shorter chain length between the end vinyl groups and the vinyl compounds having the larger value of +e behaved the more effectiveness as the crosslinking additive on the peroxide cure of EPDM and EPM.
    View full abstract
    Download PDF (898K)
  • ON THE MAXIMUM ELONGATION RATIO OF RUBBERS
    T. Kotani, M. Kawashima, S. Suzuki
    1969 Volume 42 Issue 12 Pages 1030-1035
    Published: 1969
    Released on J-STAGE: April 16, 2008
    DOIhttps://doi.org/10.2324/gomu.42.1030
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The maximum elongations of sulfur-cured IR-CZ, IR-DPG, IR-TT, NBR, IIR, Silicone rubber and so on, αb•max were examined to recognize the generality of the equations proposed in the previous papers.
    αb•max=1.24(Mc/MZ)1/2
    (αb•max)0=1.24(Mc/MZ)1/2(ν/ν0)1/2
    where ν, Mc, M and Z are respectively cross-linking density, the molecular weight between cross-links, that of the monomeric unit and a measure of stiffness of the chain. Z was estimated from the stress-strain curves and the birefringence.
    As the experimental results, the reduced elongation ratio, (αb•max)0 was found to be about constant with respect to the kind of rubber, and αb•max was correlated with Z for rubbers tested here except IIR. (αb•max)0 of cis-polyisoprene was hardly changed by the cure system and the crosslinking density, but influenced by the kind of rubber. Thus, the maximum elongation ratio was correlated with a structual factor and others.
    View full abstract
    Download PDF (410K)
  • RUPTURE CHARACTERISTICS OF RUBBER-LIKE POLYMERS
    (PART III) PARAMETER DESCRIPTION OF STRAIN AT BREAK IN GUM VULCANIZATES
    T. Kotani, M. Kawashima, K. Ninomiya
    1969 Volume 42 Issue 12 Pages 1036-1043
    Published: 1969
    Released on J-STAGE: April 16, 2008
    DOIhttps://doi.org/10.2324/gomu.42.1036
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The general needs, the number of necessary parameters and the parameters desirable to be involved were discussed for the analytical expression to describe the temperature dependence of strain at break in gum vulcanizates in regard to the research project aimed at correlating quantitatively the quality of rubber products with their various molecular characteristics.
    After examining the experimental data obtained for various kinds of samples, the following empirical equation was found to have general applicability to the data.
    (αb/αb•max)=1+Bllog[(T-Tg)/(Tmax-Tg)] (Tg<T≤Tmax)
    =exp[-Bh(T-Tmax)] (T>Tmax)
    Here Tg and Tmax represent respectively the glass temperature and temperature where the extension ratio at break, αb reaches its maximum value, αb•max. T stands for the absolute temperature. Bl and B are the material parameters whose values were found to range respectively from 0.4 to 0.6 and from 0.010 to 0.015 for the samples examined.
    View full abstract
    Download PDF (677K)
  • [title in Japanese]
    [in Japanese]
    1969 Volume 42 Issue 12 Pages 1043
    Published: 1969
    Released on J-STAGE: April 16, 2008
    DOIhttps://doi.org/10.2324/gomu.42.1043
    JOURNAL FREE ACCESS
    Download PDF (77K)
  • [title in Japanese]
    [in Japanese]
    1969 Volume 42 Issue 12 Pages 1044-1064
    Published: 1969
    Released on J-STAGE: April 16, 2008
    DOIhttps://doi.org/10.2324/gomu.42.1044
    JOURNAL FREE ACCESS
    Download PDF (1833K)
  • [title in Japanese]
    [in Japanese]
    1969 Volume 42 Issue 12 Pages 1065-1084
    Published: 1969
    Released on J-STAGE: April 16, 2008
    DOIhttps://doi.org/10.2324/gomu.42.1065
    JOURNAL FREE ACCESS
    Download PDF (1315K)
  • [title in Japanese]
    [in Japanese]
    1969 Volume 42 Issue 12 Pages 1085-1086
    Published: 1969
    Released on J-STAGE: April 16, 2008
    DOIhttps://doi.org/10.2324/gomu.42.1085
    JOURNAL RESTRICTED ACCESS
    Download PDF (225K)
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top