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Predecessor
Volume 46, Issue 12
Displaying 1-12 of 12 articles from this issue
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[in Japanese]1973 Volume 46 Issue 12 Pages 973-983
Published: December 15, 1973
Released on J-STAGE: October 16, 2009
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[in Japanese]1973 Volume 46 Issue 12 Pages 984-991
Published: December 15, 1973
Released on J-STAGE: October 16, 2009
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[in Japanese]1973 Volume 46 Issue 12 Pages 992-1001
Published: December 15, 1973
Released on J-STAGE: October 16, 2009
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[in Japanese], [in Japanese]1973 Volume 46 Issue 12 Pages 1002-1008
Published: December 15, 1973
Released on J-STAGE: October 16, 2009
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1973 Volume 46 Issue 12 Pages 1009-1011
Published: December 15, 1973
Released on J-STAGE: October 16, 2009
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SOLVENT CRACK GROWTH OF RUBBER (PART II)Katuhide MANABE, Kunihiko NAKASHIMA1973 Volume 46 Issue 12 Pages 1012-1015
Published: December 15, 1973
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSExperiments on the solvent crack growth of rubber were attempted in various solvents such as a romatics, esters and ketons. The rate of crack growth shows a linear relation against the extension and this rate differs with solvents, but the critical extension shows a constant value in spite of the difference in solvent. The crack growth rates tend to decrease with an increase of the molecular volume of the solvent. When the rate of crack growth is plotted against the diffusion constant of solvent into rubber, lines with different gradients were obtained for ketones, esters and aromatics. However, when the crack growth rate was plotted against the swelling rate of rubber, the plots became a straight line.
Therefore, it was found that the rate of crack grow h depended on the diffusing time of a definite volume of solvent into rubber.View full abstractDownload PDF (628K) -
SOLVENT CRACK GROWTH OF RUBBER (PART III)Kunihiko NAKASHIMA, Katuhide MANABE1973 Volume 46 Issue 12 Pages 1016-1020
Published: December 15, 1973
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSThis report relates to the effects of the density and the type of crosslinking of NBR on the rate fo solvent crack growth. The rate of solvent crack growth increases with an increase of crosslinking, while critical extensions decrease. As to the type of crosslinking, the rate of crack growth of C-C bond is higher than that of any other type such as C-S-C or C-Sx-C, whereas the critical extension ratio shows the reverse tendencies.
Critical extension ratios are plotted against Mc1/2, where Mc is the number average molecular weight between crosslinks, showing a linear relation. The slopes of these straight lines do not depend upon the type of crosslinkings, but when these straight lines are extrapolated to zero critical extension, Mc of C-C bond becomes higher than those of others. Discussion was made on these results with respect to the homogeneity and heterogeneity of the crosslinking.View full abstractDownload PDF (921K) -
SOIVENT CRACK GROWTH OF RUBBER (PART IV)Katuhide MANABE, Kunihiko NAKASHIMA1973 Volume 46 Issue 12 Pages 1021-1025
Published: December 15, 1973
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSThe solvent crack growth of rubber compounded with various carbon blacks or calcium carbonate was measured to investigate the influence of filler in rubber. It was found that the rate of crack growth of filler-loaded rubber was in a linear relation to extention ratio as well as NBR gum valcanizates described in the previous paper.
The rate of crack growth passes through a minimum as the filler loading is increased and it is dependent on the particle size of the fillers; small particles show much greater effect than coarse ones. When the rates of crack growth of high loading samples were plotted against the extension ratio, characteristic plots consisting of two straight lines having a bending point were obtained.
It was found that the extension ratio of this “bending point” depended upon the loading and particle size of filler and was in a linear relation to the root of distance between fillers.
The slope of the line above the bending point varies with kinds of the filler; that of carbon black loading becomes sharp and that of calcium carbonate loading is dull in comparison with the line below the bending point.
Discussion was made on both results with respect to the differnce of the surface activities.View full abstractDownload PDF (926K) -
Yoshihiro Todani, Shizuye Sagaye1973 Volume 46 Issue 12 Pages 1026-1030
Published: December 15, 1973
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSThe changes in polymer dispersion in various blended rubber vulcanizates after repeated elongations were observed with an electron microscope.
As a result, it was found that the polymers, which were initially in unevenly island-like dispersion (0.11μdimension), became agglomerated into several round-shaped groups. This phenomenon can only be explained by assuming that each part in the specimen has undergone deformation at varying degrees.
In the case of SBS block-copolymer, the styrene phases, which were initially rod-like shapes, were fractured into small particles by repeated elongation. This fracture occurred partially in the scale of μ.View full abstractDownload PDF (1957K) -
Yoshihiro Todani, Shizuye Sagaye1973 Volume 46 Issue 12 Pages 1031-1038
Published: December 15, 1973
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSThe electrical resistance of carbon blak-filled rubber vulcanizates was measured under repeated elongations (and retractions) and stress relaxation. Also the changes of carbon black distribution due to elongation were observed with an electron microscope.
It was found that the electrical resistance of vulcanizates decreased under stress relaxation, but increased by repeated elongation.
It was found under an electron microscope that partial deformation occurred in the specimens on a scale of μ and the carbon black distribution became more heterogeneous under large elongation.
We supposed that the carbon black particles in the places where the contents of carbon black became higher under elongation may agglomerate and finally a very heterogeneous structure may appera after repeated elongations.
It was also found that the carbon black in SBR vulcanizate showed a different behavior from those in N R and BR.View full abstractDownload PDF (1870K) -
Yoshihiro Todani, Nagatoshi Sugi, Hirokatsu Seya1973 Volume 46 Issue 12 Pages 1039-1045
Published: December 15, 1973
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSUsing the balloon type extension apparatus, we determined the tensile stress, tensile strength and ultimate elongation of various kinds of vulcanizates under uniform biaxial extension for comparison with those under simple extension.
Whereas the tensile stress under uniform biaxial extension increased remarkably at large deformation in the cases of gum vulcanizates and non-reinforcing filler containing vulcanizates, that of carbon-black filled vulcanizates showed only a slight increase.
The differences of tensile strength or ultimate elongation between various vulcanizates are smaller under uniform biaxial extension than under simple extension. Then it may be said that a fracture directly reflecting the structure of rubber phase is more liable to happen under uniform biaxial extension.
We knew that the vulcanizates showing higher tensile strength under uniform biaxial extension than under simple extension exhibit lower tear strength.View full abstractDownload PDF (1103K) -
1973 Volume 46 Issue 12 Pages 1046-1047
Published: December 15, 1973
Released on J-STAGE: October 16, 2009
JOURNAL RESTRICTED ACCESSDownload PDF (382K)
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