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Predecessor
Volume 43, Issue 6
Displaying 1-9 of 9 articles from this issue
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[in Japanese]1970 Volume 43 Issue 6 Pages 417
Published: 1970
Released on J-STAGE: April 16, 2008
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[in Japanese]1970 Volume 43 Issue 6 Pages 418-425
Published: 1970
Released on J-STAGE: April 16, 2008
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[in Japanese]1970 Volume 43 Issue 6 Pages 426-441
Published: 1970
Released on J-STAGE: April 16, 2008
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[in Japanese]1970 Volume 43 Issue 6 Pages 442-443
Published: 1970
Released on J-STAGE: April 16, 2008
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[in Japanese]1970 Volume 43 Issue 6 Pages 443
Published: 1970
Released on J-STAGE: April 16, 2008
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Y. Umezawa, M. Hirai, N. Horii1970 Volume 43 Issue 6 Pages 452-456
Published: 1970
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSStatic and dynamic properties of Alfin rubber compounds were studied. From the experimental results, it is considered that Alfin rubber compounds are excellent in abrasion resistance and crack growth resistance.
To confirm these characteristics, tests of tires consisting of Alfin rubber tread compounds were carried out in comparison to emulsion SBR/BR-blended compound being generally used for tread, and the following conclusions were obtained:
(1) Tread compounds containing Alfin rubber were found to be about 17% better than emulsion SBR/BR tread in wear resistance and to have good cracking resistance.
(2) In addition, static and dynamic traction forces of treads containing Alfin rubber were found to be more than 10% better.
(3) Braking characteristic was found to be slightly better.View full abstractDownload PDF (316K) -
(PART VIII) ROLLING FRICTION COEFFICIENTK. Yamamoto1970 Volume 43 Issue 6 Pages 457-464
Published: 1970
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSRolling friction measurements have been made with an apparatus of Flom and Bueche type on various vulcanized rubber samples to test the validity of the theory advanced by Takemura and others.
Effects of the loading and the rolling velocity conditions as well as temperature on the rolling friction coefficient of each sample were found reasonably predictable from the Takemura′s Equation (Eq. (I) in the text).
The observed value of the rolling friction coefficient of each sample was compared to that calculated with the Takemura′s Equation from the data on the linear viscoelastic properties of the same sample. It is concluded therefrom that the dependence of the rolling friction coefficient on the viscoelastic properties of a sample can be fairly well described by the relationship given by Takemura.View full abstractDownload PDF (594K) -
(PART II) STRUCTURE OF FILLED VULCANIZATES AND THEIR STRUCTURAL CHANGE DUE TO MECHANICAL STIMULIK. Fujimoto, T. Nishi1970 Volume 43 Issue 6 Pages 465-476
Published: 1970
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSThe structure of vulcanized rubbers filled with carbon blacks has been investigated by using the pulsed NMR method.
The molecular motion and the amount of the degenerated rubber phase (C-phase) formed around the carbon blacks and the rubber phase (A-phase) apart from the carbon blackes have been analysed. The structure of filled vulcanized rubber has been compared with that of vulcanizates without fillers and that of plastics from the view point of the degree of molecular motion. At the same time our previous exprimental results on structural change of filled vulcanizates due to mechanical stimuli have been re-examined and the following concousions have been deduced.
(1) The vulcanized rubber filled with carbon blacks consists of a quasi-glassy plase (C-phase) around filler particles and a liquidlike phase (A-phase) apart from filleres. The molecular motion of rubber molecules in the former phase is rather restrictive and it gives the NMR half width of about 5 gauss. The thickness of the C-phase is about 45Å in the case of ISAF grade Carbon blacks, although it depends upon the reinforcement of the fillers.
On the other hand, the molecular motion in the latter phase, though it depends on the crosslink density, is as free as in the liquid, showing NMR half width of about 60-120m gauss in the case of natural rubber when the chain length between crosslinks Nl is in the range of 1000-150Å.
(2) A carbon black filled vulcanizates is a micro-heterogneous mixture of thermodynamically different phases-liqidlike phase and solidlike phase. Each phase changes to the more stable state by mechanical stimuli, namely to the more disordred state and to the more ordered state, respectively and the heterogeneity in the system develops.
The degree of change in both phases is propotional to the amount of the C-phase formed around the fillers.
(3) As the motion of rubber molecules in the A-phase is almost similar to that in the liquid, the fillers in the vulcanizates move to their more stable positions at a given condition by rotational and translational motions under mechanical stimuli.View full abstractDownload PDF (1099K) -
(PART VIII) STUDIES ON NATURAL RUBBERY. Kozai, E. Hata, Y. Ikeda1970 Volume 43 Issue 6 Pages 477-482
Published: 1970
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSThe graft copolymerization of acrylonitrile on hydrochlorinated rubber was carried out in toluene under various conditions. The results are as follows: Benzoyl peroxide and azobisisobutyronitrile are effective initiators for graft copolymerization. There is a maximum degree of grafting in a certion range of initiator concetrations (for 2.27-4.36mol/l). The degree of grafting increased rapidly with an increasing of ratio acrylonitrile to hydrochorinated rubber. The highest grafting efficiency (for 80-90%) was obteined under the polymerization at 80°C, and a hydrochlorinated rubber concentration of 3-4vol%.
Some physico-chemical properties of the graft-copolymer were determined and discussed.View full abstractDownload PDF (437K)
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