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Predecessor
Volume 43, Issue 12
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[in Japanese]1970 Volume 43 Issue 12 Pages 945-961
Published: 1970
Released on J-STAGE: April 16, 2008
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[in Japanese]1970 Volume 43 Issue 12 Pages 962-965
Published: 1970
Released on J-STAGE: April 16, 2008
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[in Japanese]1970 Volume 43 Issue 12 Pages 966-974
Published: 1970
Released on J-STAGE: April 16, 2008
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[in Japanese]1970 Volume 43 Issue 12 Pages 975
Published: 1970
Released on J-STAGE: April 16, 2008
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(Part X) TENSION TESTINGIsao Furuta1970 Volume 43 Issue 12 Pages 976-981
Published: 1970
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSRegarding tensile tests in JIS. as a sort of the constant-strain-rate uniaxial extension test, an equation to estimate the results from the test in JIS. was obtained essentially by combining that proposed by T. L. Smith for representin 8 the equilibrium uniaxial stress-strain data and those given in the linear theory of viscoelasticity to describe the constant-strain-rate stress-strain data.
Experimental data obtained for various samples were found to be fairly well predicted with the equation herein obtained for those of 100%, 300% and 500% moduli and also of the ultimate elongation, but a numerical front factors of a value of three was found to be necessary to give a good estimation.View full abstractDownload PDF (488K) -
(VI)EMPIRICAL EQUATIONS FOR TEMPERATURE DEPENDENCE OF TENSILE FRACTURE PROPERTIESK. Fujimoto, T. Migita1970 Volume 43 Issue 12 Pages 982-991
Published: 1970
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSFrom our previous studies on fracture mechanism for carbon black filled non-crystallized rubber vulcanizates, it was cleared that the ultimate tensile properties can be described by the five main factors; (1) glass transition temperature Tg, (2) rigid component fraction in copolymer xB, (3) network chain densities in rubber matrix v, (4) volume fraction of carbon blackø, and (5) volume fraction of dense structure around carbon black C*. On the basis of semi molecular mechanism, we obtain the empirical equations for temperature dependence of tensile strength σb and ultimate elongation εb, as followed.
(low temperature region)
(high temperature region)
Using the nineteen constants (σ*b pure, ε*b, pure, A1, A2, B1, B2, a1, a2, H1, H2, h1, h2, p1, p2, k1, k2, m1, m2, Tc) given arbitrarily, these equations were examined in comparison with experimental results for various SBR vulcanizates. The relations between these equations and time-temperature dependence or failure envelope were also disddussed.View full abstractDownload PDF (722K) -
(Part VII) STUDIES ON TRANSITION REGION OF MIXING STATES OF STYLENE-BUTADIENE-STYLENE BLOCK COPOLYMER-GENERAL PURPOSE POLYSTYLENE RESIN BLENDKunio Satake, Kanto Shinki, Tsutomu Teraoka, Sadao Ibe1970 Volume 43 Issue 12 Pages 992-995
Published: 1970
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSMill blend of styrene-butadiene-styrene block copolymer (styrene content: ca. 25%) and general purpose polystyrene resin was studied in succession to the previous paper. The state of polymer disperision was studied paying attention to the transition region of mixing states of blends which appears in the curves of blend ratio dependence of physical properties.
It was found that a rigid continuous phase of general purpose polystyrene resin was not formed easily in the transition region of mixing states of this blend system, different from the case of polybutadiene rubber-general purpose polystyrene resin blend. Further studies on this phenomenon have shown that comparatively strong mutual interaction between polystyrene blocks of styrene-butadiene-styrene block copolymer and general purpose polystyrene resin might be responsible for this fact.View full abstractDownload PDF (369K) -
(Part II) PROPERTIES OF THE BUTADIENE-RUBBER CONTAINING ISOXAZOLINE RINGK. Tada, Y. Numata, T. Katumura, K. Yoshioka1970 Volume 43 Issue 12 Pages 996-1001
Published: 1970
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSSome rubbers having butadiene units were modified with 1, 3-dipolar system, benzohydroxamic chloride-triethylamine.
In the case of high cis-containing polybutadiene (BR-01) and polyisoprene (IR-305), the modifications were not successful, but in the case of low cis-containing polybutadienes and emulsion-polymerized SBR, the modified rubbers had good green properties and much improved vulcanizate properties. Following conclusions were obtained.
1) The viscosities at 100°C of the modified Diene (polybutadiene produced by alkyl lithium catalyst) and EBR (polybutadiene produced by emulsion polymerization) were lower than those of the original rubbers, but SBR were higher. The tensile properties of the unvulcanized compounds were improved very much in all modified rubbers.
2) The vulcanizates of the modified rubbers showed improved tensile strength, tear strength and cut growth. Other properties such as heat-build-up, brittle point, transition temperature changedlhardly. The abrasion resistance of the modified rubbers was a little lower than that of the original rubbers.
3) As SBR was blended with the modified rubbers, the tensile properties of unvulcanized compounds decreased very sharply to those of SBR compound, and those of vulcanizates were lower than the proportionally estimated values from those of the two components at each blend ratio. The minimum values were obtained at the 50/50 blend ratio.View full abstractDownload PDF (400K) -
(Part I) Decrease of Mooney Viscosity of Chloroprene Rubber by MasticationT. Takagi, T. Hashimoto, N. Kawasaki, H. Nakamoto1970 Volume 43 Issue 12 Pages 1002-1005
Published: 1970
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSThe samples of chloroprene rubber polymerized at 15, 45 and 75°C, respectively, were masticated on an open mill controlled at arbitrary temperatures.
The decrease of the Mooney viscosity of the sample caused by the mastication could be approximately showed by the following equation
ML=(ML0-ML∞)exp(-at)+ML∞,
where ML0 and ML∞ are the initial and the final Mooney viscosities of the sample, respectively, and a is a rate constant independent of the mastication time.
Though it is generally considered that the polymer chain is degraded mechanically by passing through a narrow slit between the two rolls, this equation has no exact physical meaning.
In this report, the authors estimated experimentally the final Mooney viscosity ML∞, and concluded that the chain scission of chloroprene rubber is caused mainly by the high shear stress between the two rolls.View full abstractDownload PDF (308K) -
(Part II) Variation of Molecular Weight Distribution of Chloroprene Rubber by Mill MasticationT. Takagi, T. Hashimoto, N. Kawasaki, S. Kido1970 Volume 43 Issue 12 Pages 1006-1010
Published: 1970
Released on J-STAGE: April 16, 2008
JOURNAL FREE ACCESSVariation of molecular weight distribution of mercaptan modified polychloroprene by roll mastication was followed by the GPC method.
An attempt was made to explain the mechanism that chain scission of polymer occurs mechanically in its center under high shear stress by the assumption that the rate constant of the chain scission is proportional to the α-th power of molecular weight, MWα, using the concept of stepwise reaction.View full abstractDownload PDF (329K)
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