Nihon Reoroji Gakkaishi
Online ISSN : 2186-4586
Print ISSN : 0387-1533
ISSN-L : 0387-1533
Volume 2 , Issue 1
Showing 1-9 articles out of 9 articles from the selected issue
  • Shigeharu Onogi
    1974 Volume 2 Issue 1 Pages 1-2
    Published: April 20, 1974
    Released: November 20, 2012
    JOURNALS FREE ACCESS
    Download PDF (174K)
  • Sakuro MURAYAMA, Hideo SEKIGUCHI
    1974 Volume 2 Issue 1 Pages 3-6
    Published: April 20, 1974
    Released: November 20, 2012
    JOURNALS FREE ACCESS
    In order to analyze the time-dependent behavior of normally consolidated clays, a nonlinear theory with a single integral representation has been developed. The equilibrium properties, as well as the time-dependent properties, are taken into consideration in the theory. It is shown that the proposed theory can be reduced to a simple form by making use of the results of stress relaxation tests on a normally consolidated clay. After experimentally confirming that the relationship between the excess pore water pressure and the maximum principal strain is only slightly influenced by the rate of strain, it was shown that the proposed theory successfully ex-plains the rheological properties of the clay under conditions of undrained steady shearing. Furthermore, the effect of time on the undrained compressive strength in the case of a plastic clay which has been consolidated under no lateral strain is also discussed. The results suggest that the proposed theory is possibly applicable for analyzing the time-dependent behavior of Ko-consolidated samples of normally consolidated clays.
    Download PDF (487K)
  • Yozo JUJO, Masaaki SAITO, Hiroaki IKEDA, Yuzo MASUDA
    1974 Volume 2 Issue 1 Pages 7-11
    Published: April 20, 1974
    Released: November 20, 2012
    JOURNALS FREE ACCESS
    Recently, molecular motions of some vinyl-polymers in solution have been investigated by means of dynamic mechanical and dielectic methods. Masuda et al. reported that a molecular model of relaxation for PMA (low molecular weight)-acetone solution can be imagined in terms of the rotational isomer of a head-tail bond in the polymer chain, and for PMA (high M. W.)-acetone solution, a double relaxation was found in the same frequency region. A second relaxation for PMA (high M. W.)-acetone solution was related to the spreading of the polymer chain, on the basis of the solvent dependence of the relaxation processes.
    In this study, the temperature dependence of the ultrasonic absorption and velocity for PMA (Mw=88×104) in 1, 2-dichloroethane (good solvent) solution and also for PMA (Mw=108×104) in toluene (poor solvent) solution were measured to investigate the difference between the thermal relaxation and the second relaxation. Double relaxation due to two kinds of molecular motion was found in the case of the high molecular weight PMA-toluene solution. It was concluded that one of them was a thermal relaxation due to the rotational motion of a chain segment, and the other was an order-disorder configuration transition based on the association of segments in a polymer sphere. A single relaxation was found in the low molecular weight PMA-1, 2-dichloroethane solution, the relaxation frequency of which has a transition temperature at 20°C. It was concluded that the molecular motion of the relaxation process below the transition temperature was that of the order-disorder configuration transition, as in the high molecular weight PMA-toluene solution.
    Download PDF (854K)
  • Takayoshi MATSUMOTO, Chiyoji HITOMI, Shigeharu ONOGI
    1974 Volume 2 Issue 1 Pages 12-16
    Published: April 20, 1974
    Released: November 20, 2012
    JOURNALS FREE ACCESS
    The dynamic and steady-flow properties of disperse systems of styrene-divinylbenzene copolymer particles in a polystyrene solution have been measured over wide ranges of frequency, rate of shear, and strain amplitude by means of a cone-and-plate rheometer. The main results may be summarized as follws: (1) The suspensions show linear viscoelastic behavior at strain amplitudes less than 0.5%, but striking nonlinearlities at larger strains. However, at very long time-scales, these systems are linearly viscoelastic, independent of the strain amplitude, and a yield stress cannot be observed. (2) The nonlinear viscoelastic functions G1′ and G1″ decrease with increasing strain amplitude, but they are almost independent of strain for strains larger than 50%, over the entire frequency range. (3) The relaxation spectrum of the suspensions consists of two parts: one is the box type portion in the long time-scale region, where the intensity is very sensitive to strain; the other appears in the short time-scale region and is not so sensitive to strain. Thus, the rheological behavior of these suspensions cannot be understood without considering the three-dimensional network structure formed by the suspended particles. On the basis of these results, a new concept for the yield stress of suspensions is proposed and discussed.
    Download PDF (960K)
  • Kaoru UMEYA, Takashi KANNO, Kazuo KATO
    1974 Volume 2 Issue 1 Pages 17-22
    Published: April 20, 1974
    Released: November 20, 2012
    JOURNALS FREE ACCESS
    The non-Newtonian behavior of ZnO-water suspensions stabilized with various amounts of sodium hexamethaphosphate was studied in a coaxial cylinder viscometer under conditions of constant shear rate and cyclic shearing. In both cases, the samples were sheared at a high shear rate for 5 minutes and then allowed to rest for 5 minutes prior to measurements. This was necessary because the transient behavior of these materials is heavily influenced by the previous history of shear rate and rest periods. The ζ-potential was also measured in order to discuss the rheological behavior on the basis of the theory of colloidal stability.
    In the constant shear rate tests, rheopectic behavior was observed; the apparent viscosity in-creased with time and reached an equilibrium value. In the cyclic shearing tests, an irreversible hysteresis was observed. The up-curve showed first Newtonian and then pseudo-plastic flow with increasing shear rate; however, above a certain shear rate, dilatant behavior was observed. The down-curve showed pseudo-plastic flow, giving shear stresses higher than those of the up-curve.
    The mechanisms of the rheopexy and dilatancy observed in this study were attributed to aggregation of the particles by shear, causing them to pass over a potential energy barrier into a primary minimum in the potential energy curve.
    Download PDF (865K)
  • Makoto KAIBARA, Eiichi FUKADA
    1974 Volume 2 Issue 1 Pages 23-25
    Published: April 20, 1974
    Released: November 20, 2012
    JOURNALS FREE ACCESS
    The dynamic rigidity for bovine plasma and fibrinogen-thrombin solution was determined during clotting in the temperature range between 15°and 43°C.
    The dynamic rigidity of plasma gel increases with increasing clotting temperature. This suggests that the enzymatic activity of thrombin to polymerize fibrin increases with increasing temperature. On the other hand, the rigidity of fibrin gel clotted from the fibrinogen-thrombin solution decreases with increasing clotting temperature. This suggests that the dissociation of crosslinks between fibrin polymers takes place at a higher temperature.
    The rate constant of network formation as a function of increasing temperature increases and then decreases through a maximum for both plasma and fibrin gels. The rate constant of the dissociation reaction of the croosslink is unchanged for plasma gels but increases for fibrin gels as a function of temperature. The decrease in the network formation rate at the higher temperature may be explained by assuming the presence of an inactivated state for the fibrin poly-mers.
    Download PDF (432K)
  • Yoshiyasu SATO, Masayuki SAKURAI, Kenji HORIUCHI
    1974 Volume 2 Issue 1 Pages 26-28
    Published: April 20, 1974
    Released: November 20, 2012
    JOURNALS FREE ACCESS
    A constitutive model is developed by assuming a Maxwellian relaxation for the relaxation function ψA, ψB, ψC of the coefficients in the constitutive equation f(t)={A(t)+B(t)/α+C(t2}×(α-1/α2), where f denotes the tension based on the cross-sectional area, α denotes the extension ratio and the coefficients A(t), B(t), C(t) are given as A(t)=AD-∫t0ψA(t-τ)dτ, B(t)=B0-∫t0ψ(t-τ)dτ, C(t)=C0-∫t0ψc(t-τ)dτ, where A0, B0, C0 are the coefficients at t=0. The above equation was derived as one of the approximation equations of the expansion type from the constitutive equation for Green-Rivlin viscoelastic bodies. An experimental equation, f0=Kf, is also introduced into the equation, where f0,f, are respectively the initial tension and the relaxed equilibrium tension during stress relaxation of carbon black filled rubber; and K is a constant almost independent of the kinds of black fillers, of concentration, and of extension ratio. Stress relaxation data for HAF black filled SBR under large deformations are compared with the equation obtained.
    Download PDF (476K)
  • Hirotaro KAMBE, Masakatsu KOCHI, Teiji KATO, Shigenori KUGA, Masashige ...
    1974 Volume 2 Issue 1 Pages 29-30
    Published: April 20, 1974
    Released: November 20, 2012
    JOURNALS FREE ACCESS
    The dynamic mechanical and dielectric relaxations of an aromatic polyimide film, du Pont Kapton H, were measured. Mechanical dispersions at 1 Hz were found at 190°K(β), 370°K(β′), 520°K(β′), and 670°K (α). The lowest temperature dispersion β was assigned to a“water”dispersion. The mechanical dispersions above 370°K were discussed in reference to data given by Gillham and by Wrasidlo. By dielectric measurements we found distinct β′ and β″ dispersions. Wrasidlo also found β′ and β″ peaks in the dielectric loss curves but not a β loss; for the β loss we found a very small absorption peak. In the DSC curves, there were no marked transitions. In the case of the thermal shrinkage behavior of stretched polyimide films, as analyzed by thermomechanical analysis, we found three separate processes corresponding to mechanical loss peaks. The respective activation energies for the processes are β′ 10 kcal/mol, β′ 25 kcal/mol, and α 33 kcal/mol, which are consistent with values determined by Wrasidlo in his dielectric measurements. The molecular mechanisms of these three relaxations are discussed.
    Download PDF (296K)
  • Takashi ODA, Matsuo MAEDA, Sadao HIBI, Hiroshi MOTOGAMI, Kenji ANDO
    1974 Volume 2 Issue 1 Pages 31-34
    Published: April 20, 1974
    Released: November 20, 2012
    JOURNALS FREE ACCESS
    The difference between the dispersion of the components in two mechanically blended films of polyethylene and polypropylene was investigated by means of optical microscopic and mechanical tests. The films were cast from melts at 230°and 270°C. The results show that a film cast at 270°C has better continuity than a film cast at 230°C, both having the same composition.
    Furthermore, the results obtained by the simultaneous measurement of creep and birefringence show that the PE phase in the film of the blends deforms easier than the PP phase.
    Download PDF (1174K)
feedback
Top