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Predecessor
Volume 39, Issue 12
Displaying 1-8 of 8 articles from this issue
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Y. Ueno, T. Kasabo, T. Hanada, Y. Minoura1966 Volume 39 Issue 12 Pages 977-983
Published: December 15, 1966
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSIn this work a new method of grafting was employed, using the cyclization of natural rubber. Natural rubber generally undergoes cyclization by the protonation with a Lewis acid or a protonic acid. Therefore with a suitable monomer polymerizable with a cationic catalyst in the system, it may be expected that the cyclization and grafting reactions will take place at the same time.
Polymerization of styrene was carried out in cyclohexane solution of natural rubber with stannic chloride. It was found that the cyclization of rubber took place as well as the grafting copolymerization of styrene.
The rate of polymerization of styrene was proportional to the 2nd power of the concentration of styrene and to the concentrations of stannic chloride and natural rubber, respectively. The overall activation energy was about 6 Kcal./mole. Grafting percentage increased with increases in the concentrations of styrene and stannic chloride, and decreased with the concentration of rubber. On the other hand, grafting efficiency showed a reverse tendency. Grafting percentage could be increased to 150% by the addition of nitrobenzene, a polar solvent.View full abstractDownload PDF (1016K) -
PART I. STUDIES ON THE ANALYSIS OF DATA BY A SECOND-ORDER MATHEMATICAL MODELT. Shiga, M. Hirutani1966 Volume 39 Issue 12 Pages 984-991
Published: December 15, 1966
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSRecently the optimal program has been employed in studying the compounding of rubber, especially the analysis with contour diagrams is popular. We studied the limitations of the method when applied to the study of compounding rubber.
White filler and process oil were selected as two variable factors of the ethylene-propylene rubber compounds. Contour diagrams of several methods were compared and the following conclusions were obtained.
In some cases, the optimal program cannot be applied to the study of rubber compounds. Furthermore, in using the orthogonal array, some design points may be found to occupy a meaningless region. In many cases, it is better to use random design points, i.e., the allocation of arbitrary levels for all the factors. It is not easy to estimate the mathematical model with random design points, but will be relatively simple if an electronic computer is used.View full abstractDownload PDF (1162K) -
PAPT II. STUDIES ON THE CONSTRAINED OPTIMIZATION METHODM. Hirutani1966 Volume 39 Issue 12 Pages 992-998
Published: December 15, 1966
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSThe method of analyzing the second-order mathematical model was studied. Several methods are known as the constrained optimization methods. For example, linear programming is used when the objective function and all the constraints are linear functions. When the objective and constraints are second-order functions, a graphical analysis is applicable in case the number of variables is less than two.
Then, the author worked ont a new method using a computer to solve the constrained optimization problem when the objective and constraints are general second-order functions.
The method obtained is suitable for studying rubber compounds which meet many specifications.View full abstractDownload PDF (1227K) -
H. Shizuka, T. Azami1966 Volume 39 Issue 12 Pages 999-1005
Published: December 15, 1966
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSHeterogeneous reactions between ZnO and TT were studied, by tracer method (S35 or Zn65), in xylene, in rubber and in the solid phase, respectively. The products in every case were identified as zinc dimethyl dithio carbamate (PZ) by IR spectrum, UV spectrum and measurements of melting point. (The absorption of UV spectrum; absorption max. are 261 mμ and 285 mμ in cyclohexane, 259 mμ and 278 mμ in alcohol).
The rate of heterogeneous reaction in xylene is represented by the following equations (1) and (2). These are known as Hinohara kinetic equations.
dx/dt=Ka-x/xn… (1)
1/t In a/a-x=n/a·x/t+K/an… (2)
The values of k can be calculated as below, and the value of n s about 1 in each case.k (mole/l hr); k 110°C 9.38× 10-5 k 120°C 1.36 10-4, k 130°C 2.04× 10-4, (TT; 0.1 mol/l, ZnO; 0.1 mol/l)
It is shown that the plots oflog k against 1/T fall on a straight line, and the activation energy is about 12 Kcal/ mol. On the other hand, the activation energy can be obtained by plotting log k (k; the reaction velocity in initial stage) against 1/T and this value is about 13 Kcal/mol. It may be concluded from the value of activation energy that the rate determining step does not exist in diffusion process, but in reaction. The term ofnmeans the heterogeneity in reactivity of ZnO surface. Then, the effect of addition of small amounts of ZnO or PZ on the exchange reaction between TT and S was investigated. The inflection point shifted to earlier stage and the reaction rate was slightly increased. From a consideration of these studies, it seems most reasonable to conclude that ZnO reacts with TT and the product (PZ) accelerates the exchange reaction.View full abstractDownload PDF (1087K) -
(Part I) PROCESSIBILITY OF UNVULCANIZED RUBBER. 1K. Ninomiya, G. Yasuda1966 Volume 39 Issue 12 Pages 1006-1018
Published: December 15, 1966
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSCriticizing the works hitherto conducted on the processibility of raw rubber it is pointed out that the analytical approach is much needed towards this problem besides the existing statistical or epidemiological one. Also it is pointed out that the polymer rheology is a useful tool for the analytical study on the processibility of rubber and the main difficulties in practice are revealed.
After reviewing the history of the rubber industry, it is concluded that the best processibility is to be achieved for any kind of rubber when it exhibits the same rheological behavior exactly as that of a properly masticated natural rubber while being processed.
Proper arrangements of the available information in polymer rheology and approximate treatments of related phenomena lead to the conclusion that the relaxation spectrum of each sample can uniquely be used as a measure for the quantitative discussion on the processibility by comparing it with that of the target.
In the Appendix, the effects of molecular weight distribution on the processibility of rubber, the usefulness of the Mooney viscometer, the cold flow and the tack characteristics of rubber are discussed in connection with the conclusion obtained in the text.View full abstractDownload PDF (2890K) -
[in Japanese]1966 Volume 39 Issue 12 Pages 1019-1029
Published: December 15, 1966
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSDownload PDF (1715K) -
[in Japanese], [in Japanese]1966 Volume 39 Issue 12 Pages 1030-1040
Published: December 15, 1966
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSDownload PDF (4082K) -
1966 Volume 39 Issue 12 Pages 1041-1042
Published: December 15, 1966
Released on J-STAGE: October 20, 2009
JOURNAL RESTRICTED ACCESSDownload PDF (382K)
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