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Volume 42, Issue 6
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[in Japanese]1969 Volume 42 Issue 6 Pages 409
Published: 1969
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSDownload PDF (144K) -
[in Japanese]1969 Volume 42 Issue 6 Pages 410
Published: 1969
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSDownload PDF (123K) -
PART IV. THE ULTIMATE TENSILE PROPERTIES OF FILLED AND UNFILLED SBR VULCANIZATESK. Fujimoto, T. Migita, T. Kasuya1969 Volume 42 Issue 6 Pages 411-425
Published: 1969
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSIn order to make clear the failure mechanism of rubber vulcanizates, the ultimate tensile properties of SBR vulcanizates with and without carbonblack were investigated. To confirm the structure of these vulcanizates the measurements of dynamic modulus, dielectric loss and NMR were performed. From the results, the following conclusions were obtained.
1) In the series of SBR gum vulcanizates with various network chain densities νs, the transition temperature increases with increasing νs, but the temperature Tab, at which the maximum ultimate elongation αb, max, is obtained, scarcely changes. Though αb, max decreases with increasing νs, we cannot establish the relation that αb, max is linearly related with νs, -1/2 which is assumed from the fully stretched molecular chain and is held in NR gum vulcanizates.
2) In the series of carbonblack-filled SBR vulcanizates, αb, max changes little with increasing carbonblack fraction φ, but Tab increases with φ. In addition, “two stage phenomena” in failure envelope appear more clearly with increasing φ.
3) These results, which are mentioned above 1) and 2), are interpreted as follows: In case of pure gum vulcanizates, the relaxation time will be short with increasing νs, and in carbonblack-filled vulcanizates, the relaxation time will be long with φ.
4) In case of carbonblack-filled SBR vulcanizates, the bond ruptures mainly occur in rubber matrix, and scarcely occur on the surface of carbonblack. In addition, the proportion of the bond rupture on the filler surfaces is maximum at Tab.
5) The temperature TF2, which corresponds to the higher inflection point in failure envelope of the filled rubber vulcanizates, will show the measure of relaxation time, which means the deformation of dense rubber structure around carbonblack or the change of relative position between carbonblack.View full abstractDownload PDF (1338K) -
Y. Ueno, T. Kasabo, H. Hironaka, Y. Minoura1969 Volume 42 Issue 6 Pages 426-432
Published: 1969
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSReactions of poly (vinyl chloride) with magnesium were made to occur under various conditions, but poly (vinyl chloride) did not react with magnesium.
The reactions of poly (vinyl chloride) with benzylmagnesium chloride and allylmagnesium chloride as Grignard reagents were carried out in tetrahydrofuran at reflux temperature. It was found that the chlorine atom in the poly (vinyl chloride) was substituted with benzyl and allyl groups by the coupling reaction and that a small amount of Grignard reagent of poly (vinyl chloride) was formed by the magnesium-halogen exchange reaction. The extent of substitution increased with an increase of the reaction period and concentration of the Grignard reagent.
The polymers thus obtained became soft with an increase of the extent of substitution.View full abstractDownload PDF (519K) -
(PART VII) GREEN STRENGTHC. Tosaki, M. Takashima, G. Yasuda, K. Ninomiya1969 Volume 42 Issue 6 Pages 433-438
Published: 1969
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSAn yield value of the nominal stress appearing generally in the stress-strain diagram obtained at a con-stant rate of strain was suggested to be one of the most reasonable measures for the so-called green strength of unvulcanized rubber.
Both the yield stress, fv, and the yield strain, γv, were then correlated to the relaxation modulus in extension, E(t), and other quantities for a linear viscoelastic body. Thus we have
fY=E(t)/t=γvγ0
where γ0 stands for the strain rate applied.
An approximation of a simple power function type to the relaxation spectrum of a sample further gives a relationship such that
γY=(1-m)/m
Here m is the value of the power to the relaxation time in the approximation.
Application of those results to the experimental data on various species of rubber unvulcanizates ap-peared to be fairly successful.View full abstractDownload PDF (461K) -
(I) BLENDINGS OF THE EPDM WITH EPMM. Imoto, Y. Minoura, K. Goto, H. Harada, K. Nishihira, H. Fujita, K. ...1969 Volume 42 Issue 6 Pages 439-442
Published: 1969
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSRoll blending of EPDM with EPM was carried out. The blend rubbers were vulcanized using three different agents, i.e., sulfur, dicumyl peroxide, and brominated alkyl phenol resin. As EPM is unsuitable for sulfur or resin cure, blend rubbers are required to contain a surplus EPDM.
Both blend rubbers could be vulcanized with DCP. Physical properties of the blend rubbers are proportional to the blend ratio.View full abstractDownload PDF (256K) -
[in Japanese]1969 Volume 42 Issue 6 Pages 443-455
Published: 1969
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSDownload PDF (960K) -
[in Japanese]1969 Volume 42 Issue 6 Pages 456-463
Published: 1969
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSDownload PDF (639K)
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