NIPPON GOMU KYOKAISHI

[title in Japanese]

[in Japanese]

1972 Volume 45 Issue 4 Pages 329-337
Published: April 15, 1972
Released on J-STAGE: October 16, 2009

DOIhttps://doi.org/10.2324/gomu.45.329

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[title in Japanese]

[in Japanese]

1972 Volume 45 Issue 4 Pages 338-344
Published: April 15, 1972
Released on J-STAGE: October 16, 2009

DOIhttps://doi.org/10.2324/gomu.45.338

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[title in Japanese]

[in Japanese]

1972 Volume 45 Issue 4 Pages 345-353
Published: April 15, 1972
Released on J-STAGE: October 16, 2009

DOIhttps://doi.org/10.2324/gomu.45.345

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[title in Japanese]

[in Japanese]

1972 Volume 45 Issue 4 Pages 354-364
Published: April 15, 1972
Released on J-STAGE: October 16, 2009

DOIhttps://doi.org/10.2324/gomu.45.354

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2-Mercaptoimidazoline/6-Ethoxy-2, 2, 4-trimethyl-1, 2-dihydroquinoline/N-Isopropyl-N′-Phenyl-p-Phenylenediamine/Polymerized 2, 2, 4-tritnethyl-1, 2-dihydroquinoline/Testing Methods for Synthetic Rubber BR

1972 Volume 45 Issue 4 Pages 365-373
Published: April 15, 1972
Released on J-STAGE: October 16, 2009

DOIhttps://doi.org/10.2324/gomu.45.365

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SOLUBILITY OF ANTIOXIDANTS IN RUBBER AND RESISTANCE TO FATIGUE OF RUBBER

A STUDY ON DETERIORATION AND STABILITY OF BR AND IR (IX)

Mizuho Tanaka

1972 Volume 45 Issue 4 Pages 374-377
Published: April 15, 1972
Released on J-STAGE: October 16, 2009

DOIhttps://doi.org/10.2324/gomu.45.374

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To study the relation between the fatigue of rubber and the solubility of antioxidants in rubber, PANA (Phenyl-α-naphthyl amine), which is a soluble antioxidant in rubber, DNPPD (Sym. Di-β-naphthyl-p-phenylen diamine), which is an insoluble one, oil (softener), and the control of NR, which has no additive, were used in the test. These materials were examined by repeated tension tests in air and in inert gas. As a result of these tests, the order of the term of life in air is found :
PANA > DNPPD > oil > control while in inert gas, it is oil > PANA > control > DNPPD
That is to say, in presence of oxygen, the soluble antioxidant in rubber lasted long under the fatigue. In inert gas, the soluble one lasted long too regardless of antioxidant. Consequently, it is supposed that the resistance to fatigue is due to the relaxation of the concentrated stress by those compounding agents.

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(PART V) MECHANICAL PROPERTIES OF VULCANIZED SBR-LOW MOLECULAEWEIGHT SUBSTANCE MIXTURES

STUDIES ON HETEROGENEITY OF FILLED RUBBER SYSTEMS

K. Fujimoto, T. Nishi

1972 Volume 45 Issue 4 Pages 378-388
Published: April 15, 1972
Released on J-STAGE: October 16, 2009

DOIhttps://doi.org/10.2324/gomu.45.378

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Dynamic mechanical properties and failure characteristics of vulcanized SBR-low molecular weight substance mixtures which can be regarded as compatible systems are examined in the glassy, transition and rubbery region with varying volume content and varying softening point of the several low molecular weight substances.
Measured value of the mechanical properties is compared with the calculated value which is obtained by assuming the system to be homogeneous. In the calculation the variation in the degree of molecular motion of the system, the decrease in rubber fraction and the change in the crosslink density are considered.
Good agreement with the calculated and measured value is obtained in the glassy and transition region of the system but there is considerable discrepancy between them in the rubbery region.
It is infered to explain the discrepancy that there is phase seperation in the molecular order or there is developed a microheterogeneous structure according to the difference in the glass transition temperature between SBR and the low molecular weight substance. It is suggested that if the latter has a higher glass transition temperature than SBR, it has reinforcing effect and if the reverse is the case, it has diluting or weakening effect.

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Failure Process (Part II) Fatigue Failure under Constant Repeating Stress

STUDY ON FAILURE MECHANISM OF RUBBER VULCANIZATES (IX)

Kunihiko Fujimoto, Tetsuhiko Migita

1972 Volume 45 Issue 4 Pages 389-392
Published: April 15, 1972
Released on J-STAGE: October 16, 2009

DOIhttps://doi.org/10.2324/gomu.45.389

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In order to make clear the failure mechanism of rubber vulcanizates, the tensile failure process was studied in the previous report, following the fatigue failure process under constant repeating stress. The relations between fatigue life and morphology of fracture surface were discussed for carbonblack filled SBR vulcanizates. The fatigue failure process was classified into three phases on the basis of repeating stress conditions, as follows.
Phase I : In the region of higher repeating stress. Determined by the growth and breakdown of “fracture nuclear molecular chains group”, such as in the case of thensile failure process.
Phase II : In the region of middle repeating stress. Determined by the growth and breakdown of “fracture nuclear molecular chains group”, larger than those in the case of Phase I.
Phase III : In the region of lower repeating stress. Determined by the crack growth from the tip of local fractured defects.
To describe the fatigue failure process systematically, a critical condition was established and the qualitative molecular mechanism to fulfil that condition was discussed.

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[title in Japanese]

1972 Volume 45 Issue 4 Pages 393-394
Published: April 15, 1972
Released on J-STAGE: October 16, 2009

DOIhttps://doi.org/10.2324/gomu.45.393

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