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Predecessor
Volume 41, Issue 3
Displaying 1-10 of 10 articles from this issue
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N. Yoshimura, K. Fujimoto1968 Volume 41 Issue 3 Pages 161-164
Published: March 15, 1968
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSThe degree of mixing of vulcanized and unvulcanized SBR/BR blends was investigated by the measurement of temperature dependence of dynamic shear modulus G′ and tan δ at 10 cps. JSR # 1500 was used as SBR and JSR BR01 and EBR (emulsion polymerized polybutadiene) as BR.
The results obtained are as follows :
a) The unvulcanized SBR/BR blends represented micro-heterogeneous mixtures.
b) On the other hand, the vulcanized SBR/BR blends showed micro-homogeneous patterns in G′ and tana measurements.
c) This change of patterns was not due to heat effect during vulcanization but ascribable to network forming by cross linking.
d) This network forming effect was considered to be caused by co-cross linking between different polymers.
e) It was thus considered that the vulcanized SBR/BR blends were actually heterogeneous but showed homogeneous patterns by mutual molecular chain interactions attained by co-cross linking.View full abstractDownload PDF (700K) -
(PART III) THE EFFECT OF CROSSLINKING DENSITY ON THE PHYSICAL PROPERTIES OF POR GUM VULCANIZATEM. Ohba, S. Maeda, M. Ueda, M. Kanaoka, Y. Minoura1968 Volume 41 Issue 3 Pages 165-170
Published: March 15, 1968
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSChanging the crosslink density of gum vulcanizate obtained from POR, the effects of the crosslink density on physical properties, i. e., dynamic modulus, loss tangent (tanδ), tensile strength, hardness, tensile hysteresis, repeated tension, and heat build-up, were studied.
From the results, it was found that the physical properties of gum vulcanizate of POR was influenced remarkably by crystallinity. The degree of crystalization of POR of low crosslink density was higher than that of high crosslink density.
The gum vulcanizate of POR showed, in comparison with the other synthetic rubbers, lower heat buildup, better properties at low temperature, and higher tensile hysteresis loss.View full abstractDownload PDF (958K) -
(PART IV) CARBON BLACK COMPOUND OF PORM. Ohba, S. Maeda, M. Ueda, T. Shirakami, Y. Minoura, M. Kanaoka1968 Volume 41 Issue 3 Pages 171-177
Published: March 15, 1968
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSThe effects of carbon black on the properties of POR were studied. The effects of unsaturated contents in POR on cure rate were made clear, that is, the rate of cure was increased according to increasing unsaturated content, but the effects of Mooney viscosity and unsaturated content on the physical properties were not found.
Changing the amount of carbon blacks (HAF, SAF for 20 to 100 PHR), the reinforcement effects were tested. As a result, we found that tensile strength and tear resistance showed maximum value at 40 to 60 PHR carbon black. The other properties (modulus, permanent set, heat build-up, etc.) increased in proportion to the amount of carbon black.
Further, we studied the physical properties of several carbon black compounds (HAF, SAF, CRF, EPC, and FT). The study shows that modulus, tensile strength, heat build-up, permanent set, and so forth, increase in proportion to the amount of iodine adsorption of carbon black.View full abstractDownload PDF (1186K) -
(PART V) EFFECTS OF WHITE FILLERS ON PORM. Tsukasa, T. Nagafune, A. Nagao, Y. Minoura1968 Volume 41 Issue 3 Pages 178-183
Published: March 15, 1968
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSThe physical properties of propylene oxide rubber (POR) in white filler compounds were studied in relation to the appropriate level and type of filler. White fillers used were fumed silica, hydrated silica, clay, active calcium carbonate and calcium carbonate.
From the results, it was found that both fumed and hydrated silica pigments developed the most excellent reinforcement with an increase in the tensile strength and the abrasion resistance. On the other hand, calcium carbonate pigments did not develop any reinforcement. Clay and active calcium carbonate pigments developed an intermediate reinforcement between silica and calcium carbonate.
As the amounts of filler increased, the tensile strength reached a maximum and then decreased. This maximum tensile strength was developed at 30 phr of silica and at 40 to 60 phr of clay and calcium carbonate.View full abstractDownload PDF (844K) -
(PART VI) PEROXIDE CURE OF PORK. Azuma, K. Shikata, T. Ogura, T. Oikawa, Y. Minoura1968 Volume 41 Issue 3 Pages 184-189
Published: March 15, 1968
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSPolypropylene oxide (PPO) was not vulcanized with peroxides alone, while propylene oxide-allylglycidyl ether copolymer (POR) was vulcanized.
In the vulcanization of PPO, the combinations with coagent, such as sulfur, styrene, N, N′-(m-phenylene) bismaleinimide, or divinyl benzene were necessary. Sulfur, among these coagents, had the most favorable effects on vulcanization.
Addition of polyisocyanate compounds to a dicumylperoxide-sulfur curing system greatly improved the properties of vulcanizates.View full abstractDownload PDF (758K) -
(PART III) ON THE REINFORCEMENT OF SBR WITH XYLENE-MELAMINE RESINSChing Yun Huang, K. Ueno, S. Kawamura, K. Masawaki1968 Volume 41 Issue 3 Pages 190-196
Published: March 15, 1968
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSIt was stated in our previous paper that xylene-melamine resin prepared by modification of melamine formaldehyde resin with xylene formaldehyde had good dispersive effect on SBR and gave SBR excellent reinforcement.
In this paper, the effects of xylene-melamine resin on SBR were studied in further details. The results were obtained as follows.
1) The effect of reinforcement on SBR depended on the composition of xylene-melamine resin. A maximum value of tensile strength was obtained from a resin consisting of 80 parts of xylene resin and 100 parts of melamine resin.
2) The vulcanization rates were generally decreased by addition of xylene-melamine resin.
3) Some kinds of accelerators affected the cure rate of resin. The acidic compounds, thiurame and thiazole increased the cure rate, but, the basic compounds, guanidine and imidazole decreased it.
4) The relationship between the amount of xylene-melamine resin and its reinforcing effect on SBR was examined. Maximum value of tensile strength was shown when the resin of 25 phr was added into SBR.
5) The milling time to the optimum physical properties of reinforced SBR was somewhere between 6 and 9 minutes, the physical properties were rather reduced when the milling time was longer.
Dispersion state of resins in the cured SBR was also observed under a phase-contrast microscope.View full abstractDownload PDF (10722K) -
[in Japanese], [in Japanese]1968 Volume 41 Issue 3 Pages 197-204
Published: March 15, 1968
Released on J-STAGE: February 05, 2010
JOURNAL FREE ACCESSDownload PDF (1277K) -
[in Japanese]1968 Volume 41 Issue 3 Pages 205-218
Published: March 15, 1968
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSDownload PDF (1873K) -
[in Japanese]1968 Volume 41 Issue 3 Pages 219-226
Published: March 15, 1968
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSDownload PDF (4071K) -
1968 Volume 41 Issue 3 Pages 227-228
Published: March 15, 1968
Released on J-STAGE: October 16, 2009
JOURNAL RESTRICTED ACCESSDownload PDF (281K)
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