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Volume 64, Issue 6
Displaying 1-8 of 8 articles from this issue
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[in Japanese]1991 Volume 64 Issue 6 Pages 339-345
Published: 1991
Released on J-STAGE: July 09, 2007
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[in Japanese]1991 Volume 64 Issue 6 Pages 346-359
Published: 1991
Released on J-STAGE: July 09, 2007
JOURNAL FREE ACCESSDownload PDF (1258K) -
[in Japanese]1991 Volume 64 Issue 6 Pages 360-362
Published: 1991
Released on J-STAGE: July 09, 2007
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Koh HASEGAWA, Yutaka OBATA, Nobuo TAGATA1991 Volume 64 Issue 6 Pages 363-371
Published: 1991
Released on J-STAGE: July 09, 2007
JOURNAL FREE ACCESSCyclic elongation fatigue tests have been done from zero to constant stress level (σ) at a fixed rate of elongation, for three carbon black filled elastomers (SBR, BR, NR). Speed of crack growth and criterion size of crack that leads to macroscopic failure were related to σ by the morphological analysis of fatigue fracture surface. Diameter of the crack observed by that of striation region was increased exponentially against the number of elongation cycles. The criterion size of crack was found to obey Griffith′s criterion condition.
And the change of the internal structure of fatigue sample was estimated by pulsed NMR measurement. In the early stage of fatigue we observed characteristic change of spin-spin relaxation time T2.View full abstractDownload PDF (2431K) -
EFFECT OF SULFUR AND WATER RESISTANCEYoshiyuki IKEDA, Hidemi NAWAFUNE, Shozo MIZUMOTO, Koichi YAMAGUCHI, Ka ...1991 Volume 64 Issue 6 Pages 372-377
Published: 1991
Released on J-STAGE: July 09, 2007
JOURNAL FREE ACCESSWith the rubbers adhesion-cured onto an electroless Pd-P alloy deposit, the effect of sulfur dosage on peel strengths before and after aging in hot water was investigated. At over 0.5phr of sulfur in SBR valcanizates and over 2.5phr in NR valcanizates, cohesive failures were significantly observed. The decrease in peel strength under the excessive sulfur addition is not due to the decrease in adhesion force but increase in cohesive force of rubber which caused the drop in tear resistance. The adhesion strengths were not influenced at all after hot water aging (at 95°C for 3 days). Also any adhesion deterioration caused by amines, which were derived from the degradation of accelerators or antioxidants seemed not to be found. Thus, it appears that the electroless Pd-P alloy deposit gratly improves to hot water aging durability of peel strength of SBR or NR.View full abstractDownload PDF (672K) -
Kazuhiro FUJIKI, Katsuaki MAGARA, Norio TSUBOKAWA, Yasuo SONE1991 Volume 64 Issue 6 Pages 378-385
Published: 1991
Released on J-STAGE: July 09, 2007
JOURNAL FREE ACCESSThe introduction of amino and methylol groups onto furnace black or acetylene black by using electrophilic substitution reaction of polycondensed aromatic rings on the surface was investigated. The introduction of amino groups was achieved by the reduction of nitrated carbon black which was prepared by the treatment of carbon black with fuming nitric acid. Methylol groups were successfully introduced by the reaction of aromatic rings of the carbon black with formaldehyde in the presence of sodium hydroxide as catalyst. The amino and methylol groups introduced onto furnace black Philblack O were determined to be 0.04 and 0.12mmol/g, respectively. It was found that carbon black having amino groups has an ability to initiate the anionic polymerization of γ-methyl-L-glutamate N carboxyanhydride (NCA). In the polymerization, poly (amino acid) was grafted onto carbon black based on the propagation of the polymer from amino groups on the surface: the percentage of grafting reached to about 50%. Furthermore, the polymerization of acrylamide (AAm) was found to be initiated by a redox system consisting of ceric ion and methylol groups on the surface. In the polymerization, polyAAm was effectively grafted onto the surface because the polymerization was initiated by radicals formed on the surface by the redox reaction of methylol groups with ceric ion. Therefore, amino and methylol groups introduced by electrophilic substitution reaction were found to be available for the grafting of polymers onto carbon black having few functional group.View full abstractDownload PDF (927K) -
Norimichi YOSHITAKE, Mutsuhisa FURUKAWA, Tetsuo YOKOYAMA1991 Volume 64 Issue 6 Pages 386-394
Published: 1991
Released on J-STAGE: July 09, 2007
JOURNAL FREE ACCESSIn a previous paper concerning pyrolysis gas chromatography of polyurethanes by using silicagel column, we have reported that the pyrograms bears a close resemblance to those of polymer glycols used for preparation and suggested that the pyrograms provides a useful method of identification of polyurethanes. In this study the reference pyrograms of polyether glycols, polyester glycols, and hydroxyl-terminated polybutadiene were compared with those of polyurethanes in more detail. As a result it was concluded that the constituent polymer glycols of polyurethanes can be identified easily from their pyrograms.View full abstractDownload PDF (870K) -
[in Japanese]1991 Volume 64 Issue 6 Pages 395-396
Published: 1991
Released on J-STAGE: July 09, 2007
JOURNAL RESTRICTED ACCESSDownload PDF (248K)
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