材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
21 巻 , 224 号
選択された号の論文の28件中1~28を表示しています
  • 山本 三三三
    1972 年 21 巻 224 号 p. 355-359
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Hereunder is discussed the applicability of constitutive equations of integral type to some nonlinear non-steady viscoelastic behaviors of concentrated polymer systems. Two types of models based on Lodge's model are considered. One of them is to represent the generalization of the so-called WJFLMB model and has the after-effect function depending on the invariants of the rate-of-deformation tensor at the time of excitation. The other is the generalized WKZ model with the after-effect function depending on the invariants of the relative deformation tensor between the times of excitation and response. Both the models can well explain the rate-of-defomation dependences of the viscosity coefficient and of the normal stress differences for a steady simple shearing flow. The model depending on the rate-of-deformation is simpler and rather good than the relative deformation dependent model in the explanation of some nonlinear non-steady viscoelastic behaviors such as the stress development at the biginning of flow, the stress relaxation after stoppage of the flow, and parallel and orthogonal superpositions of small sinusoidal oscillation on the steady shearing flow. The former model is, however, not efficient enough to give cause to deformation dependence of the relaxation modulus in the stress relaxation in the usual sense for large shearing deformation.
  • 倉田 道夫
    1972 年 21 巻 224 号 p. 360-369
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Hereunder is presented a review of recent experimental studies made on the non-linear viscoelasticity of polymer solutions and melts. The subjects covered are:
    (1) Non-Newtonian viscosity behavior of narrow-distribution polymers, (2) the normal stress effect in steady shear flow, (3) the recoverable strain in steady shear flow, (4) the stress relaxation after the cessation or interruption of steady shear flow, (5) the growth of stress after the onset of the steady shear flow, (6) the recoverable strain during the approach to the steady shear flow, (7) the sinusoidal oscillation superimposed on the steady shear flow, and (8) the stress relaxation under larger shear strain. It is specially noted that the distribution function of relaxation time obtained with a constant rate of deformation is appreciably shifted to be made on short time scale, depending on the deformation rate, while the distribution function obtained with a constant deformation is not. Emphasis is also put on the key rôle of the recoverable strain measurements in the study of non-linear viscoelasticity.
  • 高見 昭, 岡 小天
    1972 年 21 巻 224 号 p. 370-372
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Hereunder is presented a consideration on the theory of distribution of the vertical stress in powder filled in a cylindrical vessel in a state of equilibrium. The same problem was treated by Janssen, but his theory was based on the assumption that the vertical stress was constant on a horizontal plane. On the other hand, experimental studies show that the vertical stress in powder in equilibrium in a cylindrical vessel does not remain constant on a horizontal plane, but changes according to the distance from the axis of the cylinder. As far as we are informed, no theory has yet been developed dealing with the variation of the vertical stress with the distance from the axis of the cylinder.
    We have developed a theory on distribution of the vertical stress, taking into account its variation with the distance from the axis of the cylinder. It is assumed that both the vertical stress and the horizontal stress are connected by Rankine's law. But in the theory proposed under this assumption the possible effect of compression is neglected. From the condition of powder in equilibrium an equation has been derived to determine the vertical stress as a function of both the distance h from the free surface of powder, and the distance r from the axis of the cylinder. A solution has been found in taking the vertical stress as expressed in Taylor's series in ξ=r/R. The boundary condition at the free surface is that the pressure at any point on the free surface is equal to the atmospheric pressure. It is shown that our theory agrees fairly well with the experimental data by taking appropriate values for the product of Rankine's coefficient and the frictional coefficient of the wall.
  • 高見 昭
    1972 年 21 巻 224 号 p. 373-375
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Hereunder is presented a theory of distribution of vertical stress in the powder in equilibrium in a conical vessel. The same problem has been treated by Aoki and Walker, but their theory were based on the assumption that the vertical stress was constant on a horizontal plane. On the other hand, Tanaka et. al. have shown that the vertical stress of the powder in equilibrium in a conical vessel is not constant on a horizontal plane, but changes according to the distance from the axis of the conical vessel. As far as we know, no theory has yet been developed dealing with the variation of vertical stress with some distance from the axis of the cone.
    We have developed a theory of distribution of vertical stress, taking into account its variation with the distance from the axis of the cone. It was assumed at first that the vertical stress and the horizontal stress were both connected by Rankine's law. The effect of compressibility has been neglected. From the condition of eqilibrium of powder an equation has been derived to determine the vertical stress as a function of both the distance z and h from the vertex of the cone and the distance ξ from the axis of the cone. A solution has been found, giving vertical stress as one of Taylor's series in ξ. The solution contains a number of arbitary constants, and it has been found that the solution shows a tendency to fit to the experimental curves of the distribution of vertical stress by choosing appropriate values for the constants.
    Thus, we have come to the conclusion that Rankine's law is not valid in the present problem. This may be understood if we remember that Rankine's law is derived from Mohr's theory of yielding. Rankine's law may be modified by considering the influence of the so-called cohesive force between the powder particles. However, it has been found that a modified Rankine's law is not sufficient to explain the disagreement of our theory with what the experiments indicate.
  • 貝原 真, 深田 栄一
    1972 年 21 巻 224 号 p. 376-380
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    The reaction order in the formation of fibrin network in the fibrinogen-thrombin solution is determined by the analysis of clotting curves obtained by dynamic viscoelasticity measurements at various concentrations of fibrinogen. It is concluded from the rheological point of view that the clotting curves for elastic modulus and loss modulus can be represented by superposition of two first-order reaction processes with different rate constants respectively. The rate constants obtained from the loss modulus are larger than those from the elastic modulus. The saturated values of the elastic moduli in the two processes increase with the increase of the concentration of fibrinogen. The amplitude dependence of the elastic modulus of the gel supports the presence of the two processes.
    The elastic modulus in the first process is proportional to the number of crosslinks between the fibrin fibers, and that in the second process is related to the non-linear elongation of fibrin fibers between the crosslinks. The loss modulus in the first process is associated with the polymerization of fibrin, and that in the second process is related to the increasing interaction between the crosslinked fibrin fibers.
  • 前田 松夫, 日比 貞雄, 清水 浩和
    1972 年 21 巻 224 号 p. 381-386
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Many investigations on the mechanical properties of plastics reinforced with glass fibers have hitherto been carried out for practical use. In the theoretical point of view, however, the plan to understanding the mechanical properties of such a composite material as FRP has not yet been developed sufficiently, because of the complicated state of its system involving adhesion to clarify the difference and relation between plastics and glass fibers and so on.
    In this study, theoretical calculations have been made of the mechanical reinforcement and anisotropy of glass fibers, with increase and orientation and other changes, by taking the Model A proposed by Whitney and Riley, and the Model B by Halpin and Tsai as a structural unit.
    On comparing the calculated results with the experimental data obtained for polyethylene, including various amount of randomly oriented glass fibers at various temperatures, and for polyester reinforced with glass thread, it is concluded that both the structural models mentioned above must be available in order to describe the mechanical reinforcement and anisotropy of FRP.
  • 松本 幸雄, 福田 英憲, 米沢 大造
    1972 年 21 巻 224 号 p. 387-391
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    The complexity of rheological properties of wheat flour dough has prompted the present study of the viscoelasticity with synthetic flour dough, which was prepared by mixing three major components of wheat flour dough, i. e. the gluten protein, wheat starch, and water.
    The results obtained can be summarized as follows:
    (1) The source of the gluten protein fractionated from the commercially available wheat flours plays an important role in knowing the creep behaviour of synthetic flour Boughs of the same composition.
    (2) The values of the creep parameters derived from the creep data decrease with increasing measure of shear stresses, so that the synthetic system exhibits non-linear viscoelastic behaviour.
    (3) The introduction of a small amount of cystein into the system is pronouncedly effective to the softening, which may be due to the introduction of thiol-disulfide interchange reactions in the protein network.
    (4) The glutenin fraction of the gluten protein is a major component in the network structure of protein in the dough system.
  • 鎌形 一夫, 遠山 三夫
    1972 年 21 巻 224 号 p. 392-396
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Hereunder is reported the study made of the rheological properties of pressure-sensitive adhesives by measurement of viscosity, Young's modulus, compliance and relaxation modulus, and the discussion made of the relationship between the Theological properties and the tackiness.
    The adhesive systems are blends of masticated natural rubber and the pentaerythritol ester of partially hydrogenated rosin.
    It is known from observations with an electron microscope and measurements of mechanical loss that the compositions containing no less than 40wt-% resin are homogeneous mixtures, and when the resin concentration exceeds 40 wt-%, the phase separation occurs and the disperse phase is resin containing a small amount of rubber.
    The tackiness measured with probe tack tester for a short contact time (0.2sec) takes the maximum value at the 60 wt-% resin concentration and for a longer contact time (2-20sec) takes the maximum value at the 70 wt-%.
    While the viscosity and Young's modulus, measured at 20°C, takes the minimum value at the 70 wt-% resin concentration, the instantaneous compliance takes the maximum value at the 60 wt-% and the steady-state compliance takes the maximum value at the 70 wt-%.
    When the wettability of adhesive to the adherent therefore reaches the maximum, the maximum in the tackiness is obtained.
    The relationship between the tackiness and relaxation spectrum was also made the subject of our discussion.
  • 植田 浩義, 深田 栄一
    1972 年 21 巻 224 号 p. 397-400
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    The fibrin clots were prepared from bovine plasma and fibrinogen aqueous solution to which thrombin was added. The clots were gently compressed, thoroughly washed with distilled water, stretched by rolling, and formed into oriented films. Shear induced piezoelectricity was observed in such films, as well as those electrically oriented during the process of gelation.
    The temperature dependence of both the piezoelectric strain-constant and stress-constant showed a marked dispersion at about 0°C. The dielectric and viscoelastic measurements also revealed two dispersions around 0°C (β) and -100°C (γ), respectively. In the β dispersion, the relaxation strength decreased, and the temperature for the maximum of loss increased with the decreasing moisture content. The relaxation may be due to the onset of the thermal motion in side-chains, which is hindered by the hydrogen-bonds formed between the adjacent molecules when the moisture content decreased. The γ dispersion is observed only in the thoroughly dessicated state and it may have been caused by the local motions of molecular chains. The presence of water appears to diminish the free volume necessary for the local motions.
  • 前田 松夫, 日比 貞雄, 野田 裕司
    1972 年 21 巻 224 号 p. 401-404
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    The mechanical anisotropy of uniaxially stretched PVA films was investigated experimentally and theoretically. The theoretical calculation of the mechanical anisotropy of the films was carried out of two structural models. The first calculation was performed by averaging the mechanical anisotropies of the oriented structural units on the basis of homogeneous stress hypothesis. On this calculation, a structural unit model was constructed by combining the orthorhombic crystallite with the isotropic amorphous phase in parallel or series to the reference axis. The other theoretical calculation of the mechanical anisotropy of the films was carried out of an averaged structural model which was obtained by averaging the orientations of crystallites and amorphous chains, respectively, and combining the averaged crystalline unit with the averaged amorphous phase in parallel and series to the stress direction. The anisotropy of amorphous phase in the averaged structural model was considered by assuming the affine deformation mechanism.
    The result obtained from every theoretical calculation shows the experimental results of the uniaxially stretched PVA films in good agreement with each other.
  • 神戸 博太郎, 加藤 貞二, 空閑 重則, 横田 力男
    1972 年 21 巻 224 号 p. 405-409
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    The polypyromellitimide exhibits an excellent thermal stability due to its rigid structure of the chain molecules. In the present paper, the mechanical and dielectric secondary dispersion of such a polymer are discussed, and are correlated to their structure. The complex dielectric properties of polypyromellitimide and its relating polymers were measured at frequencies from 30 to 3MHz in the temperature range of -90°∼120°C. The viscoelastic properties of Kapton H polypyromellitimide film were measured at a higher temperature range of 20°∼500°C by means of a torsional pendulum. The stress-strain curves of H film were measured with a tensile testing apparatus at 20°C, and the thermal contraction of a stretched H film sample was also measured with the thermo-mechanical analysis (TMA) apparatus in the temperature range of 20°∼600°C. Three dispersions have been found in these measurements. The lowest one found at -60°C has been ascribed to the absorbed water. The middle one found at 70°C has also been related to the absorbed water. The highest one, which was revealed in this work for the first time, has been assigned to rearrangement of oriented metastable molecules at higher temperatures. The experimental results of TMA and the X-ray diffraction patterns of unstretched and stretched H films support this conclusion.
  • 佐藤 良泰, 桜井 正幸, 水野 高秀, 二松 正
    1972 年 21 巻 224 号 p. 410-413
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Hereunder is presented a brief report of the test made of the samples of styrene-butadiene rubber with respect to their dynamic mechanical properties with various concentration of oil ranging from 0 to 40 PHR, at various temperatures between -80°C and 40°C at varying frequencies from 1 to 100Hz, and their dynamic shear modulus G', G" were obtained. For the data, the superposition of time-temperature, time-concentration and time-temperature-concentration was examined. The results will be summerized as follows:
    (1) The G' and G" data determined at different temperatures of each sample can be represented by a master curve by applying the method of time-temperature superposition, but the data obtained between -30°C and -50°C were scattered considerably. The shift distances logaT obtained by superposing the data at temperatures below about -5°C followed the WLF equation type, where the so-called universal values of constants in WLF equation were varied to obtain better fit. The logaT obtained at temperatures above -5°C followed the Arrhenius equation type.
    (2) The G' and G" data determind at the constant temperature for samples with different concentrations can also be represented by a master curve by applying the method of time-concentration superposition. The shift distances log aC obtained by superposing the data followed the equation presented by Fujita.
    (3) The superposition of time-temperature-concentration was found impossible.
  • 佐藤 良泰, 桜井 正幸, 清水 義雄, 香山 格
    1972 年 21 巻 224 号 p. 414-418
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Hereunder is presented a brief report of the test concerning the applicability of the following stress-strain relation f=(A+B/α+Cα2)(α-1/α2) to the stress-strain behavior of styrene-butadiene rubber (SBR) with various concentrations of oil ranging from 0 to 40 PHR, and the dependences of the values of A, B and C on oil concentration, sulfur content (crosslink density) and strain rate were examined. In the above relation, f denoted the tension at extension ratio α, A, B and C were coefficients. This relation had been obtained from the phenomenological theory of finite deformation with second order approximation to the stored energy function. The time-concentration equivalence of the ultimate properties of the data was also examind. The samples of SBR were sulfur cured with various contents of sulfur in the presence of oil at 155°C for 60 minutes. The stress-strain data were determined by means of an Instron type tester at various crosshead speeds between 8mm/min and 800mm/min at the temperature 20°C. The results will be summarized as follows:
    (1) The values of A decreased with increase of oil concentration and increased with sulfur content and they were unaffected by the strain rate.
    (2) The values of B decreased with increase of oil concentration and were almost unaffected by the sulfur content, and they showed slight increase against the strain rate at high strain region.
    (3) The values of C were very small and almost 0 for the data at crosshead speeds below 200mm/min. They decreased with increase of oil conentration and had the maximum aginst the sulfur content and also against the strain rate.
    (4) Stress at break σb data of samples with different oil concentrations could be represented by a master curve by applying the method of time-concentration superposition, and the shift distances log ac obtained superposing data followed the theory of solution type equation.
  • 松本 孝芳, 瀬川 泰彦, 藁科 珍郎, 小野木 重治
    1972 年 21 巻 224 号 p. 419-423
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Disperse systems such as various suspensions, emulsions and filled polymers show remarkable nonlinear viscoelasticity even at strains smaller than 10%. A practical and general method has been proposed to determine the nonlinear viscoelastic functions G'1, G"1, G'3, G"3, and so on by the analysis of non-sinusoidal shearing stress as a result of forced sinusoidal shear strain.
    The above nonlinear functions were evaluated for disperse systems of polystyrene solution and styrene-divinyl benzene copolymer latex at various temperatures. In general, the frequency dependence curves of all the functions are rather flat and become less sensitive to temperature as the temperature rises. To the curves at different temperatures, the so-called time-temperature superposition can be applied; the shift factors determined in the course of horizontal shifts of curves for various functions are quite the same, and are independent of the strain amplitude. The master curves of the nonlinear functions manifest plateaus in the low frequency region, where the polymer solution itself shows rapid changes in G' and G". The height of the plateaus increases with increasing latex content.
  • 今田 清久, 高柳 素夫
    1972 年 21 巻 224 号 p. 424-427
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Measurement was made of the pressure below which the steady state rate of extrusion is negligibly slow, and above which it grows with steep slope against increasing extruding pressure, i. e. extrusion pressure, as the function of entrance angle α of cone shaped dies. The extrusion pressure increases with increasing α. This tendency, which can not be explained with the equation of the preceding paper, was analyzed according to the method of the slip line analysis. Several slip line fields were obtained with high frictional coefficient of μ=0.2 and of degree of processing as high as possible. The stress fields around the exit of the dies affect the extrusion pressure.
    The profile of the longitudinal section, wide at entrance and narrow at exit, is presumed to be suitable for smooth extrusion.
  • 柴山 忠雄
    1972 年 21 巻 224 号 p. 428-431
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    A theory was proposed to predict the process of unidirectional filling of a uniformly elongated flat cavity with a thickness, 2Y, and a width, 2Z, by a non-crystallizable thermoplastic at a constant temperature, TI, under a constant injection pressure, PI. The filled length, Λ, was related to the filling time, t, by an equation, Λ=ΛKJ(t/tK), where tK=tE/M and ΛK=(tKDINK)1/(n+1)Y. J(σ) evolved from a set of equations, J(σ)=∫σσI=0jI)dσI, and (j(σ))-1/n=γ(σ)+eσσσI=0eIjI)dσI. In the scheme: tE=ρωY2/4κ, where ρ, ω, or κ is the density, the specific heat, or the thermal conductivity, respectively, of the cooling layer of the thermoplastic in the cavity; M=2(n+2)θ2/n where θ=(TII-TM)/(TI-TM); n or Ψ(T) is the non-Newtonian index or the fluidity, respectively, of the melt, where T specifies the temperature; TII is the temperature at which Ψ(TII)=EFF. Ψ(TI), where EFF is a constant (≤1) taken somewhat arbitrarily to be 0.5 for schematic division of the thermoplastic in the cavity into the flowing layer and the solidified layer; TM is the temperature of the wall of the cavity; DI=D0Ψ(TI)(PD0)n, provided D0 or τ0 is a unit shear rate or a unit shear stress, respectively, for expression of the power law, DD0Ψ(T)(ετ/τ0)n, relating the shear rate of the melt, D, with the shear stress, τ, where ε=-1 for τ<0 and +1 for τ>0; PD=PI-PM, where. PM is the atmospheric pressure; NK=Nγn+2 where N=(n+2)-1 and γ=(1/2) exp (1/2); and γ(σ)≡(QM(σtK)/QK)-1/n provided that QK=2Z.2Y.ΛK/tK, where QM(t) is the flow rate through the channels preceding the cavity when the end be opened freely into the air without the cavity. If all the channels preceding the cavity are isothermal, γ(σ)≡a constant, γi, which vanishes if the melt enters from the cylinder directly into the cavity. Law of R. L. Ballman et al. of exponential decrease in speed of flow front is proven for the case where γ(σ)≡γi≤(n+1)1/(n+1), giving the time constant, B, equal to tK/n(1-n(γin+1/(n+1)n+1)1/n). Calculated fill-outs and calculated time constants agree with the experimental results of H. L. Toor et al. The present theory presupposed that the thermoplastic in the cavity can be divided into the inner layer, in which the temperature is TI, and the outer layer, in which the temperature falls down to TM following such a linear profile like that in the case of stationary conduction. The thickness of the inner layer, 2YI, was equated, by a set of assumptions, to (1-(tU/tE)1/2)
  • 小山 公夫, 和田 英一
    1972 年 21 巻 224 号 p. 432-435
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    To elucidate the mechanism of high speed tensile fracture of polymeric substances the fracture energy, W, is compared with the integrated loss tangent, L, obtained by integrating the loss tangent from 0°K to the temperature at which W was measured.
    W was determined by the oscillograph of flywheel type high speed tensile tester (testing speed 5m/sec).
    W is almost proportional to L for ten straight polymers except polycarbonate (PC), while the increase of W is more marked than that of L and the proportionality does not hold for PC and the blend polymers of polyvinylchloride with impact-resisting material, i.e., methyl methacrylate-butadiene-styrene graft copolymer.
  • 升田 利史郎, 太田 靖彦, 南出 昌彦, 小野木 重治
    1972 年 21 巻 224 号 p. 436-439
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Hereunder a report is presented of measurement made of the viscoelastic properties of concentrated solutions of star-shaped polystyrenes. From the frequency dependence of the storage shear modulus G' and loss modulus G" the characteristic parameters in terminal zone, such as zero-shear viscosity η0 and steady-state compliance Je0, have been evaluated. The dependence of these parameters on the concentration have been discussed and compared with those of concentrated solutions of linear polystyrenes.
    For the star polymers, the zero-shear viscosity reduced to the iso-free volume state, f=0.0608, is proportional to (w2ρ)6 and (w2ρ)1 at higher and lower concentrations, respectively, than the critical concentration, where w2ρ is the concentration in g/ml. The critical concentration for entanglement was evaluated to be 0.23g/ml for the star-shaped polystyrene having the molecular weight of 407000. The concentration dependence of steady-state compliance of the solutions of star polymer can be divided into three parts. The steady-state compliance is proportional to (w2ρ)-1 at low concentrations below 30wt%and to (w2ρ)-2 in the concentration range from 30 to 70wt%. In both the regions, Je0 is proportional to the molecular weight. At higher concentrations, Je0 increases rapidly passing through the minimum at about 70wt% but is independent of molecular weight. The molecular weight dependece of Je0 in the entanglement region and its rapid increase at extremely higher concentrations for the star polymers are quite different from those for linear polymers described in our recent papers. The entanglement compliance JeN0 of the solution of star polymers is proportional to (w2ρ)-2 above the critical concentration, which is similar to that of linear polymer.
  • 佐枝 繁, 鈴木 理夫, 小川 正夫
    1972 年 21 巻 224 号 p. 440-444
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Melt viscosities of polyethylene fractions were studied. The fractions of the polyethylene polymerized by a slurry process using the Phillips type chromium oxide catalyst in a poor solvent showed a peculiar melt flow behavior compared to the usual linear polyethylene fractions. The former showed a considerably higher melt viscosity and stronger extent of non-Newtonian behavior than the latter in the high molecalar weight region, above 5×104.
    Nevertheless, there is no difference between the two series of fractions in the solution behavior, such as the relation between the inherent viscosity and the weight average molecular weight Mw, or the radius of gyration and Mw. In addition, the existence of microgels which may be a cause of the high viscosity of the polymer melt was not proved.
    From the fact that the polyethylene fractions in question have smaller terminal vinyl groups determined by the IR spectrum than the usual linear fractions at the same number average molecular weight Mn, together with the results cited above, it was presumed that they include star type molecules by a few percents having long chain branches centered by the very fine particle of the catalyst.
  • 藤山 光美, 鍵山 安弘, 四方 和夫, 東 敬一
    1972 年 21 巻 224 号 p. 445-449
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Hereunder is given the report of investigation made of melt rheology of high density polyethylene.
    Its linear viscoelasticity, capillary flow properties and molecular weight parameter were measured with plate relaxometer, Koka Flow Tester and gel permeation chromatography, respectively.
    It is found that there are intimate correlations among the slope of relaxation modules curve, non-Newtonian flow behavior, the Barus effect and molecular weight parameter, MZ·MZ+1/MW, respectively.
  • 中村 良, 吉岡 直哉
    1972 年 21 巻 224 号 p. 450-452
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    The non-Newtonian viscosity derived from the previously proposed constitutive equation7) was expressed as follows,
    η(γ)=∫0H(λ)1/2α2[1/A(α)]dλ, A(α)=∫0e-x-α2x2dx, α2=1/2βλγ
    where H(λ) was the relaxation spectrum and λ, γ, and β were the relaxation time, shear rate and a nondimensional parameter of order 1, respectively. When polymers are approximated in their narrow-distribution H(λ) by
    H(λ)={H1/1-δ00, λ0≤λ≤λ1, δ001 Otherwise
    the non-Newtonian viscosity calculated from these equations can be superposed as shown in Fig. 1. If λ1 is replaced by the natural time λN defined by λN=η(0)J(0), which is more directly related to measurable quantities, the reduced shear rate in Fig. 1 becomes
    βδs/1+δ0λNγ
    where J(0) is steady-state compliance and δs=1+1.8δ00.86.
    Prest's data8) of J(0) are expressed in terms of entanglement density E as follows
    J(0)/JRc=1.22E/1+0.22E, E=M/Mc or CM/(CM)c
    where JRc is the Rouse steady-state compliance at the critical molecular weight Mc. If this experimental equation is used with assumptions that β is independent of M and δ0-1=E, the relation between the characteristic time λch and M is to be expressed as
    λch∝η(0)E/1+0.34E.
    This is in the same relation as Graessley's, and is applied to the narrow distribution of polydimethyl siloxane melts9) with fairly good agreement as shown in Fig. 2. The solid line in this figure shows the viscosity curve at δ0=1 in Fig. 1.
  • 栄永 義之, 倉田 道夫, 杉江 勉, 田村 幹雄
    1972 年 21 巻 224 号 p. 453-458
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    The steady-state compliance Je as a function of the molecular weight M and the concentration c for polymer solution can be expressed as:
    Je=αM/cRT for smaller values of c or M
    M0/c2∼3 for larger values of c and M
    Here α and β are constants and RT is used in its usual meaning. The second behavior of Je is characteristic of highly entangled system. In the concentration range where the transition from the first to the second behavior occurs, the Je displays the maximum.
    Either of the two relaxation spectra, A and B, are found to be compatible with these observed behaviors of Je. These are:
    (A) HW(τ)=1/2cRT/Mec/τ)1/2 0<τ<τc
    HI(τ)=1/2(1-gN)cRT/Mec/τ)1/2 τc<τ<τ1
    HB(τ)=1/hgNcRT/Me τl<τ<τm
    τc1E-2, τmcE3.5, τlmeh(1/E-1)
    (B) HW(τ)=1.75/3cRT/Mec/τ)2/3 0<τ<τc
    HZ(τ)=1.75/3(1-gN)cRT/Mec/τ)2/3 τc<τ<τ1
    HB(τ)=1/hgNcRT/Me τl<τ<τm
    τc1E-1.5, τmcE3.5, τlme1.75h(1/E-1)/2
    The former corresponds to the Rouse theory, while the latter to the Zimm theory. Here, τ1 represents the maximum relaxation time of the original Rouse or Zimm theory, Me is entanglement spacing, E is the number of entanglement point in a molecule, hence E=M/Me, and gN and h are parameters representing the intensities of HI and HB, respectively.
    The viscosity η, storage modulus G' and loss modulus G" are also calculated on the basis of these spectra. These results are qualitatively in agreement with the observed one, particularly in the case of high value of h and low value of gN.
  • 伊藤 良夫, 完戸 俊助
    1972 年 21 巻 224 号 p. 459-462
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    The upper (or second) Newtonian, viscosities (η) of poly (dimethyl siloxanes) of different molecular weights were determined with a capillary viscometer driven by means of N2 gas pressure. In order to diminish an experimental error, the reservoir of the viscometer was planned so as to have its much greater radius than that of the capillaries used. By the introduction of such a combination of capillaries and a reservoir, the upper limit of measurable shear rate was increased to 4.3×106sec-1.
    These polymers η can be sorted into three groups according to their molecular weights, those below Mc', those above Mc' or up to Mc, and those above Mc. (Mc' is the critical molecular weight at which the increases in the density and in the activation energy of flow with increasing molecular weight saturate, and Mc is the critical molecular weight at which the entanglement between the polymers begins.)
    The polymer below Mc' has a Newtonian behaviour throughout the whole shear rate range. The polymer above Mc' up to Mc is non-Newtonian fluid, and its upper Newtonian viscosity depends on the molecular weight. In the case of its being above Mc, the flow curves of the polymers join in the upper Newtonian region, and η is almost independent of the molecular weight.
  • 木村 博, 山口 拓治, 井町 正樹, 柳川 昭明
    1972 年 21 巻 224 号 p. 463-468
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    In this paper, the adaptability of multiple integral equation of the constituents to nonlinear viscoelastic behaviors in uniaxial stretching, for two kinds of polyethylene having different crystallinity, has been investigated. And the principle of a generalized superposition has been tested in respect of its stress relaxation, of its constant rate of elongation, and its two steps-stress relaxation experiments made by using only kernel functions G1(t), G2(t, t), G3(t, t, t), G4(t, t, t, t).
    The first kernel G1(t) is obtained from the data on nonlinear stress relaxation test, which agrees fairly well with the stress relaxation modulus in linear range. The calculated value of G1(t) from the relation between the stress and the strain rate in the constant rate of elongation test, also agrees with both the above mentioned values. These result mean that the superposition in the linear terms in the integral equation of the constituent holds true.
    The behaviors under the two steps-stress relaxation tests depend strongly on the additional strain, and the effects of the first strain are irregular. These tendencies differ from the analytical results given out in the fourth order theory. Only the dependencies of input time of additional strain is, but quantitatively, qualitatively similar to the theory. Then, the fourth order theory in the integral equation of its constituent is not efficient enough to describe the complex nonlinear viscoelastic behaviors of polyethylene.
  • 梅屋 薫, 磯田 武信, 小泉 源三, 加藤 和男
    1972 年 21 巻 224 号 p. 469-475
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    Hereunder is presented a brief report of the investigation that was made of the flow behaviors of clay-water suspensions, using a Couette type viscometer usable in a wide range of shear rates.
    The flow curves (rotational velocity ω vs. torque T) have been obtained at various pH values which may be the effectual determinant of the internal time scale τ as well as at various time derivatives of rotational velocity ω and various maximum rotational velocities ωmax corresponding to the external time scale t.
    The flow behaviors can be grouped into typical three classes as follows,
    (1) plastic
    (2) negative thixotropic
    (3) positive thixotropic
    The dependence of shearing torque on pH value measured at 90 r.p.m. indicated the minimum point at pH≈7.5.
    The analytical treatments have been developed using the mechanical simulation models constructed with the internal clay structure revealed in the sedimentation experiments.
    The dependence of flow behavior on the external time scale was also investigated using the electric circuit simulation models constructed to analyze its time sensitive properties especially, from which were obtained, the qualitative correspondences to the flow behaviors.
  • 野村 浩康, 加藤 重男, 宮原 豊
    1972 年 21 巻 224 号 p. 476-479
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
    The ultrasonic absorption in solution of polyvinyl acetate in toluene was measured in the frequency range from 1 to 60MHz. The temperature range was from -20°to 60°C, and the concentration of the solutions was 5.42g/100ml. The degree of polymerization of the sample of polyvinyl acetate was 900.
    The plot of Δ(α/f2) against frequency was represented by a single relaxation curve over the whole temperature range. With the rising temperature, the relaxation frequency fr increased and the absorption maximum per wavelength μmax decreased.
    The energy difference ΔH0 and the activation energy ΔH21 were estimated from the change of temperature of the absorption on the basis of two-state model. The values obtained were: ΔH0=1.36kcal/mol, and ΔH21=1.0kcal/mot.
  • 1972 年 21 巻 224 号 p. 480-485
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 林 紘三郎
    1972 年 21 巻 224 号 p. 486-492
    発行日: 1972/05/15
    公開日: 2009/06/03
    ジャーナル フリー
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