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Predecessor
Volume 45, Issue 7
Displaying 1-6 of 6 articles from this issue
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[in Japanese]1972 Volume 45 Issue 7 Pages 625-639
Published: July 15, 1972
Released on J-STAGE: October 16, 2009
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[in Japanese], [in Japanese]1972 Volume 45 Issue 7 Pages 640-665
Published: July 15, 1972
Released on J-STAGE: October 16, 2009
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[in Japanese]1972 Volume 45 Issue 7 Pages 666-669
Published: July 15, 1972
Released on J-STAGE: October 16, 2009
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S. Yabuta1972 Volume 45 Issue 7 Pages 695-700
Published: July 15, 1972
Released on J-STAGE: February 05, 2010
JOURNAL FREE ACCESSAn application of the extreme theory to the analysis for the facture phenomena of vulcanized rubbers under constand engineering stress is presented. The distribution function, which can describe the statistical fluctuations of observed fracturing time, is given theoretically.
This function can be derived by transformation of the random variable from a distribution function of tensile data under constant strain rate. The analytical form is given by;
Π (tb) =exp [- {log {(tb) / (tb)1} /log {(tb)2/ (tb)1}} ασ],
-∞<log (tb) <∞, log (tb)2≥log (tb)1
log (tb) ≥log (tb) 1, ασ>0,
where log (tb) 1 and log (tb) 2, the smallest value of logarithmic fracturing time and the characteristic logarithmic fracturing time, respectively, are location parameters and ασ is dimensionless scale parameter.
The numerical analysis by using the published data in the reference leads to the following results; The applicability of this function to experimental data is verified to be reasonable, In a given vulcanized rubber, the characteristic logarithmic fracturing times decrease linearly with initial loads.
On the other hand, the scale parameter is not affected them. Then, the fluctuations of the observed fracturing times under a given initial load can be described by making the former relationship clear numerically.View full abstractDownload PDF (1145K) -
Yutaka Kuwabara, Katuhiro Ishikawa, Teizo Kotani1972 Volume 45 Issue 7 Pages 701-708
Published: July 15, 1972
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSTo correlate the chemical structure and physical properties of polyisoprene, polyisoprenes were synthesized with anisole-butyl lithium system varying cis-content from 90 to 40% and keeping the average molecular weight and the distribution to be constants. The polymers were press-cured with dicumyl peroxide and the physical properties were measured to suggest the following conclusions; (1) Glass transition temperature was well correlated with the microstructures. (2) In transition region, the shape of relaxation modulus against time was much similar to each other and the difference was reflected on the glass temperature. (3) In rubbery region, the strage modulus was independent of the microstructure but depended on the density of cross linked chain. (4) The loss modulus and loss tangent were increased with the decrease of cis-content. (5) Assuming the shape of the relaxation spectra as Aθ-m, the constant, m, was increased with decrease of cis-content. (6) Tmax, at which the maximum elongation at break was observed, was shifted from 100° to-40°C by the chemical structure. (7) The back bone chain was stiffened mainly with 3, 4-structure. (8) Combining these facts with heat build-up, durability, extensibility and so on, high cis-polyisoprene would be more desirable than low cis-polymers for rubber products such as tires.View full abstractDownload PDF (1269K) -
1972 Volume 45 Issue 7 Pages 709-710
Published: July 15, 1972
Released on J-STAGE: October 16, 2009
JOURNAL RESTRICTED ACCESSDownload PDF (292K)
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