材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
15 巻 , 152 号
選択された号の論文の28件中1~28を表示しています
  • 中川 鶴太郎
    1966 年 15 巻 152 号 p. 265-270
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    It is generally considered to be a difficult work to make analysis of rheological constants of the colloidal substances from the microscopic point of view on account of their complicated nature. For the interpretation of their mechanical properties from the technological viewpoint, however, there are many cases in which their phenomenological observation is sufficient. Measurement has been made, for example, of the dynamic viscoelasticity of the paste of rice starch from various provinces. Obvious relation has been taken notice of between the elasticity of starch gel and the taste or flavor of the corresponding rice. There is another example demonstrating the efficacy of rheological measurement by which creep viscosity of some candies has been estimated and compared with their flow and tackiness in practical use.
    Most dispersed systems are known to behave as non-linear materials; carbon-black suspensions or starch pastes show strong tendency of non-Newtonian viscosity, thixotropy or non-linear viscoelasticity. There are some cases, however, in which typical linear behavior is observed. D.J. Shaw (1963) reports that ice cream behaves as a typical linear material; its creep compliance curve is perfectly independent of stress, as long as the strain is kept small, in spite of the fact that it has a composite structure of ice grains, fat particles and a network of protein. Shaw assumes that the factor responsible for its creep behavior is not ice nor fat crystals but the network of denatured protein, and that the linear behavior comes from the rubber-like elasticity of the network.
    In the present article the author proposes to discuss two problems, i.e., the problem of structure formation in dispersed systems and that of mechanical stability of colloidal dispersions.
    (1) Structure formation in dispersed systems.
    The concept of structure formation in colloidal systems has long been one of the working hypotheses in colloid chemistry along with the concept of solvation or hydration.
    Structure formation is obviously demonstrated in some cases. M.J. Forster and D.J. Mead (1951) measured electrical conductivity of carbon-black suspension in oil in the rotating-cylinder vessel, and observed marked decrease of conductivity in case of flow and its rapid recovery by settling.
    There are cases, however, in which this concept is not successfully applicable. The filler reinforcement in rubber, for example, that was once interpreted in connection with the structure by carbon-black particles in rubber matrix, is now explained as a result of a strong quasi-covalent linking between the polymer molecules and the pigment particles.
    The author has been engaged in the visco-elasticity measurement of dispersed solid systems of some pigments in asphalts and pitches. The result shows that these systems behave as a comparatively linear materials in mechanical properties. They are thermo-rheologically simple, and moreover, the so-called shift law, analogous to the time-temperature reduction law, holds in the effect of pigment concentration on the creep compliance. The concept of structure formation is applicable to this case, and the nature of the structure can be discussed.
    (2) Mechanical stability of colloidal systems.
    Some colloidal dispersions rapidly lose their stability by strong agitation, even in laminar flow shear, and coagulate and precipitate.
    The problem was originally treated by Smoluchowski, and recently modified and satisfactorily applied to the shear flow coagulation of polystyrene latex by D.L. Swift and S.K. Friedlander (1964).
  • 梅屋 薫, 磯田 武信, 石井 忠
    1966 年 15 巻 152 号 p. 271-274
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    Observation has been made of some solid-liquid suspensions and liquid-liquid dispersions in respect of their flow properties using capillary flow viscometer and co-axial cylindrical viscometer.
    The resulting flow curves will properly be recognized as generalized Newtonian flow or the so-called Ostwald flow, because the flow curve has initially shown Newtonian behavior, followed by non-Newtonian, and concluded by Newtonian pattern. These characteristics can be seen in Fig. 3.
    In the chemical engineering, the plots of the friction factor f to the Reynold's number Re are utilized to detect the occurrence of turbulence.
    In the non-Newtonian regions, these plots deviate from the linearity law as shown in Fig. 5. This deviation is, in the view of the author, to be used as well to detect non-Newtonian behavior in the flow properties of the suspensions or emulsions.
    The detection of the turbulence in the flow from the deviation in the linear relation in the plots of f:Re curves, is based on the occurrence of the abrupt change in the flow profiles. Non-Newtonian flow properties of the suspensions and emulsions are observed at the points of the occurrence of the abrupt change in the flow units, as this change in the flow units is followed by the change of the flow profiles. This deviation from the linear relation can be utilized to detect non-Newtonian behavior.
  • 西村 二郎
    1966 年 15 巻 152 号 p. 275-278
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    Calculation has been made of viscosity of concentrated suspensions of spherical particles. A term which is proportional to Re2 is estimated in the viscosity-concentration relation, where Reynolds number Re is composed of the rate of shear, the radius of a particle and the kinematic viscosity of the medium.
    Based on the cage model presented by R. Simha, a spherical enclosure was placed around a central particle. The disturbance of the original flow by the presence of the particle was considered to vanish on the surface of the cell.
    The coordinate axes are taken to be unconcerned with the rotation of the particle, so that the Navier-Stokes equation is free from the effect of Coriolis force and centrifugal force. The boundary conditions, however, need to be somewhat changed.
    The velocity field and the pressure are expanded into power series of the rate of shear. The Navier-Stokes equation and the equation of continuity are solved successively for several values of a/b, the ratio of the radii of the particle and the cell, up to the second approximation, a zeroth approximation being Simha's solution obtained from the Stokes approximation.
    Calculations have been performed by digital computers, and the final results are as follows:
    η'/η=1+17.1ξ(1-1.2 Re2+…) for a/b=0.7,
    η'/η=1+53.0ξ(1-98.3Re2+…) for a/b=0.8,
    η'/η=1+406ξ(1-5610Re2+…) for a/b=0.9,
    where η' and η are the viscosities of the suspension and the medium, respectively and ξ is the volume fraction of the particles.
  • 森 芳郎, 神保 元二, 岩本 文男, 細矢 正好, 杉山 保次郎
    1966 年 15 巻 152 号 p. 279-282
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    The extruding flow characteristics of carbon paste for electrode have been examined experimentally by the authors of the present paper. The extruding apparatus and nozzles used in the experiment are shown in Fig. 1. The type of the nozzle (the outlet diameter d, the convergent angle A, etc.), the temperature of the paste and the inner wall of the cylinder and nozzle, Tp and Tw, are selected as the experimental variables.
    The relation between the piston velocity V and the extruding piston pressure P is represented as the experimental results in Fig. 2-(1)(2)(3). From these results, new experimental equation
    (V-V0)=K(P-P0) (1)
    is derived as the fundamental equation of Bingham plastic body in place of Eq. (2), which has hitherto been used.
    It is found that P0 is affected by none of the nozzle factors and conditions other than the convergent angle of nozzle at nozzle inlet, A. P0 is named by the authors as “the ultimate limit of the extruding pressure”. The values of P0 against A are shown in Table I. As regards V0, the imaginery extruding piston velocity at the ultimate limit pressure, the physical meaning is not clear at this moment, but fairly simple relation is found as is shown in Fig. 3 and Eq. 4. The relationships between fluidity K and other factors (Tp, Tw, d) are found as are shown in Fig. 4.
  • 後藤 廉平, 清水 清
    1966 年 15 巻 152 号 p. 283-286
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    The hydrogel of Wyoming bentonite shows characteristic slip patterns under a critical shear stress i.e. the shear strength. The critical shear stress, or the shear strength, and the shear modulus have been measured by various methods over a wide range of concentration.
    The shear modulus increases with increasing bentonite concentration, as is shown by Curve I in Fig. 5. This is similar to the general feature of polymer gels. Curve II in Fig. 5 shows the relation between the shear strength and the concentration. Curve I and Curve II suggest that a proportional relationship holds good between the shear modulus G and the shear strength σ.
    Fig. 6 shows that the shear strength of bentonite gels lie between G/10 and G/30 over the whole concentration range examined. This result accords approximately with the value (G/30) derived theoretically for the shear strength of crystals by Mackenzie8) without assuming the effect of internal flaws. Buchdahl10) has pointed out also that the ratio G/σ for various polymers takes the value nearly equal to that predicted by Mackenzie.
    It appears that bentonite gels have a network structure analogous to polymer gels, and their shear strengths are related to the shear moduli, the critical shear strain taking values between 1/10 and 1/30 although it may not always be explained by assuming an atomistic mechanism as proposed by Mackenzie.
    Thus, the following mechanism is proposed for the slip fracture of bentonite gels. Under the critical shear stress or strain, the card-house of the bentonite gel breaks down one upon another starting from the point of stress concentration; then the slipping is induced by the orientation of bentonite leaflets in the direction of maximum shear. The orientation of bentonite particles is confirmed partly by the birefringence on shearing the bentonite gel between the two transparent plates.3) Below the critical stress, the gel creeps or yields very slowly.
  • 福島 正義, 種谷 真一, 曽根 敏麿
    1966 年 15 巻 152 号 p. 287-290
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    Processed cheese was made at two different rates of heating (10°C/min, 12.5°C/min). Immediately after emulsifying cheese, the specimens were stored at 5°C and 25°C respectively. During the storage of processed cheese, its viscosity and yield value were measured by means of a cone penetrometer, its instantaneous elasticity and stress relaxation by means of a compression type relaxometer, and the stability of emulsion by the oil-off test.
    General the viscosity, elasticity and yield value of processed cheese increase with the lapse of the storage time, and its stability of emulsion becomes slightly lower. In two months, its viscosity increases by about 70 percent at 5°C storage, by about 50 percent at 25°C respectively. As the result of stress relaxation shows, its instantaneous elasticity increases by about 40 percent at 5°C storage, by about 50 percent at 25°C respectively, and the relaxation time obtained from a simple model during the storage showed the minimum after 15 days.
    Processed cheese made at a lower rate of heating posseses higher viscosity, elasticity and yield value than that processed at higher rate of heating. And also processed cheese made of younger ripened cheese is harder than that made of older kind.
    It is considered that the increase of viscoelasticity is due to crystallization of fat in an early stage of storage and to the formation of complete network structure of casein in a later stage.
  • 新井 義夫, 上谷 長俊
    1966 年 15 巻 152 号 p. 291-293
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    The colored smoke trails from jet planes are generated by volatilizing colored smoke oils with hot exhaust gases from the jet engines. The colored smoke oil is a slurry, which is a mixture of selected dye with petroleum base oil.
    The colored smoke oil is a non-Newtonian fluid subject to the following power law.
    S=η'Dn (1)
    where S is the shearing stress, D the rate of shear, η' the consistency index, and n the flow-behavior index.
    The following experimental equations were derived at low rates of shear.
    η'=η0exp(kC) (k>0) (2)
    n=exp(-k'C) (k'>0) (3)
    where η0 is the viscosity of the base oil, C is the concentration of the dye, and k and k' are the constants characteristic to the kinds of dyes.
  • 岡 小天, 高見 昭
    1966 年 15 巻 152 号 p. 294-296
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    In a cone and plate viscometer a cone with a wide vertical angle is placed on a horizontal flat plate. The generator of the cone makes a very small angle α with the plate which is of the order of one degree to two degrees. The wedge-like space between the cone and the plate is filled with liquid to be investigated. Let the cone be fixed; the plate rotates with a constant angular velocity Ω around the axis of the cone. It is the purpose of this paper to find a general relationship between the torque M on the plate and the angular velocity Ω for a non-Newtonian liquid specified by an arbitrary flow curve.
    The relationship between M and Ω for a Newtonian steady flow has already been presented by several authors. Thus the formula M=(2πa3/3)·(ηΩ/α) has been derived, where a is the radius of the plate and η is the coefficient of viscosity. One of the most important characteristics of a cone and plate viscometer lies in the fact that the rate of shear is practically constant throughout one sample. Thus this type of viscometer is quite suitable for the measurement of non-Newtonian liquids.
    With regard to the motion of the liquid, the following assumptions are made: (1) the liquid is incompressible: (2) the motion of the liquid is laminar: (3) the motion is steady: (4) no body force acts on the liquid; (5) the motion has an axial symmetry; (6) each liquid particle moves on a circle on the horizontal plane perpendicular to the axis of rotation; (7) there is no relative motion between the walls and the liquid in immediate contact with the walls; (8) the end-effect is neglected. The assumption (9) means utter disregard of centrifugal forces, and as well as the assumption (2) is allowable for small values of Ω.
    We take a spherical coordinate system r, θ and φ whose origin is at the vertex of the cone. If we assume that the angular velocity ω of a liquid particle around the axis of the cone is a function of θ alone, then the shear stress τθφ is given by τθφ=c/sin2θ, where c is a constant. For a non-Newtonian liquid specified by an arbitrary flow curve f(τ), we get
    ω=1/2∫c/cos2αc/sin2θf(τ)/√τ(τ-c)dτ, Ω=1/2∫c/cos2αcf(τ)/√τ(τ-c)dτ
    The constant c is related with the torque M on the plate by the relationship M=c·2πa3/3. For a special case of a non-Newtonian liquid obeying power law flow curve f(τ)=kτn the following formula has been obtained:
    M=2πa3/3(Ω/kα)1/n
    We have also studied another special case of a Bingham body specified by a plastic viscosity and a yield value. For a non-Newtonian liquid specified by a flow curve f(τ)=Σn=1Anτn, An can be determined from the experimental relationship between Ω and M.
  • 黒岩 城雄, 中村 亦夫
    1966 年 15 巻 152 号 p. 297-301
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    It is assumed that the substances described in the present paper have elements of viscoelastic mechanism which are non-linear at large stresses, but become linear at small stresses in behaviors of flow and internal deformation. In this case the generalized Maxwell formula (1) may be reduced to Eq. (2) at the terminal region of stress relaxation following non-Newtonian flow.
    dσ(t)/dt=σmj=1j(t)/dt=σmj=1{-σj(t)/τj} (1)
    dσ(t)*/dt=σmj=1j(t)*/dt=σmj=1{-σj(t)*j°} (2)
    The asterisk in the equation refers to small stresses. τj°is the relaxation time of the jth mechanism in its ordinary sense at small stresses. By integrating Eq. (2),
    σ(t)*mj=1σj(0)*e-tj° (3)
    where σj(0)*, as an integration constant, is the extrapolated value of the stress to t=0, under which the viscoelastic mechanisms obey Newtonian and Hookean laws. Dividing Eq. (3) by γ:
    σ(t)*/γ=σmj=1ηj(0)*e-tj° (4)
    where ηj(0)*j(0)*/γ. On the analogy of the linear viscoelastic theory ηj(0)* seems to be equal to ηj°=τj°Gj°which may prevail in the viscoelastic behaviors under small stresses. If t>>τm°(the slowest relaxation time), Eq. (4) will become:
    σ(t)*/γ=ηm(0)*e-t/τm° (5)
    where the mechanisms of smaller relaxation time than τm°are neglected. According to the theory presented here, the relaxation curves plotted by log{σ(t)/γ}vs. t must become a single straight line at the final process of relaxations, independent of γ values under the steady flow.
    However, the experimental curves for the materials investigated here become almost straight lines in parallel after the initial rapid relaxations. This phenomenon may be interpreted by the following formula.
    ηm(0)*≡τm°Gm(0)*≠τm°Gm°≡ηm° (6)
    Therefore, the effects of non-Newtonian flow seem to have influence on the whole processes of the relaxation and to be characterized as follows; the maximum relaxation time is not altered, but the distribution function Gm°is depressed with increase of the shearing rate under the flow. These phenomena must be derived from the shear break-down of secondary structures under the shear, where the secondary structures seem to contribute mainly to the slowest relaxation mechanism. The evidence of structural break-down of the samples under the flow is certified by the method of Jobling et al..
    By comparison of dependencies of ηm(0)* and ηa on γ, the following relations are expected:
    limγ→0ηm(0)*m°≅η=limγ→0ηa (7)
    log ηa vs. logγ and log ηm(0)* vs. logγ curves at various concentrations seems to be subject to reduction to the master curve, respectively, by the identically reduced variables for both cases.
    τm°increases exponentially with concentration in Na-PAA solutions.
  • 田中 秀次郎, 坂西 明郎, 金子 元三, 古市 二郎
    1966 年 15 巻 152 号 p. 302-306
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    In view of the theories of viscoelastic properties of dilute polymer solution dealing with the state at infinite dilution, we have introduced the following intrinsic quantities corresponding to infinite dilution, the complex intrinsic rigidity, [G*]=limc→0(G*-iωηs)/c; the dynamic intrinsic viscosity, [η*]= limc→0*s)/ηsc; and the limiting relaxation time, (τp)0=limc→0τp(c)=limc→0Kpsp/c)M/RT. Here Kp is the relaxation time factor determined by the theories.
    The dimensionless functions of the intrinsic rigidity and viscosity are derived for random coil polymers from the Rouse-Zimm theories as follows,
    [G']M/RT=Σpωs2Kp2/(1+ωs2Kp2), [G"]M/RT=ΣpωsKp/(1+ωs2Kp2),
    [η']/[η]=ΣpKp/(1+ωs2Kp2), [η"]/[η]=ΣpωsKp2/(1+ωs2Ks2),
    ωs=ω(τp)0/Kp=ωηs[η]M/RT,
    where K1=0.608 for the Rouse theory and K1=0.422 for the Zimm theory. The same functions are derived for rod-like polymers from the Kirkwood-Auer and dumbbell model theories as follows,
    [G']M/RT=Bωs2K2/(1+ωs2K2), [G"]M/RT=AωsK+BωsK/(1+ωs2K2),
    [η']/[η]=AK+BK/(1+ωs2K2), [η"]/[η]=BωsK2/(1+ωs2K2),
    where A=1/5, B=3/5 and K=5/4 for the K-A theory, and A=1/3, B=1/2 and K=6/5 for the dumbbell model theory.
    The intrinsic rigidity and the dynamic intrinsic viscosity are both obtained by means of torsional crystal method at frequencies of 19.6kc, 39.2kc and 117.7kc, and all the measurements are confined within concentration range 0.1 to 0.7%.
    The results for polyisobutylene (PIB) in benzene at the temperature of 24.0°C agree with the Zimm theory (nondraining case). In the previous study it was shown that PIB in cyclohexane (good solvent) is partially-free-draining. It appears that the draining effects have correlation with excluded volume effects.
    The results for poly-γ-methyl-D-glutamate (PMDG) and poly-γ-benzyl-L-glutamate (PBLG) in helix solvents show that the K-A theory gives qualitatively a good first approximation to viscoelastic behavious of α-helix molecules in dilute solution. The internal freedom of α-helix molecules is under strong restrictions and it is considered as consisting of rigid rod-like molecules.
  • 山本 三三三, 田中 秀次郎
    1966 年 15 巻 152 号 p. 307-311
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    Investigation has been made on viscoelastic properties of moderately concentrated high-polymer solutions of the order of small percentage. Tschoegl, Ferry et al. have developed a general theory on the viscoelasticity of random coiled chain polymers, adopting into it the so-called hydrodynamic interaction effect and the excluded volume effect between the segments from the well-known Rouse-Zimm theory, Making a comparison between their theoretical complex modulus and experimental ones, they have pointed out that the hydrodynamic interaction seems to decrease with increasing concentration of solutions and increasing molecular weight of polymers. With increase of interpolymer interactions the polymers will behave with increased free-draining coils.
    This is rather a strange thing from the theoretical view-point. It even betrays some discrepancy between the theory and the experimental results in some cases. Though the Tschoegl's calculation shows the relation G"-ωηs>G' excepting very high frequency region corresponding to the minimum relaxation time, there are some systems that give the inverse relation G"-ωηs<G' at moderately high frequency region.
    In the case of concentrated solutions or melts of polymers, there exists the flat, so-called“box” region of relaxation spectrum due to the entanglement of polymer chains in the longer relaxation time region than the“wedge”region corresponding to the mechanism described by the Rouse-Zimm-Tschoegl's theory. Even in our moderately concentrated solution, the relaxation spectrum may have the box region to some extent, though the entanglement is not so remarkable. This effect may decrease the average gradient of spectrum as a whole as the reduction of the hydrodynamical interaction.
    In this paper, we assume the relaxation spectrum
    H(lnτ)={τ τα<τ<τc=1
    1 1=τc<τ<τM
    0 otherwise
    α=0.63 for non-draining (Zimm's) case
    α=0.50 for free-draining (Rouse's) case
    and calculate the complex modulus G' and G" for some values of maximum relaxation time τM. Our complex modulus is qualitatively in good agreements with the experimental results carried out by Ferry et al. It is also pointed out that the value of τM in this case, ≈20, is well explained by Hayashi's theory of weakly coupled rubber-like network structure.
  • 村上 謙吉, 草野 孝衛, 中村 茂夫, 木瀬 秀夫, 小野 勝道
    1966 年 15 巻 152 号 p. 312-316
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    Polybutadiene is considered to be most promising elastomers in synthetic rubber industry as the result of remarkable improvement made on this material in recent years so that it contains now nearly all cis-1, 4 in its structure. The chemorheological study of this material is in this way becoming a very interesting subject.
    For the measurement of stress relaxation two kinds of samples were used, the samples that were subjected to thoroughgoing extraction in aceton and benzene at room temperature after complete vulcanization, and therefore free from all chemical residue that might act as cross-linking agents, and the samples that were not subjected to extraction, and therefore retain chemical substances that might act as cross-linking agents. As was found by A.V. Tobolsky and others with natural rubber when f(t)/f(0) was plotted against log t, all cis-1, 4 polybutadiene showed the Maxwellian decay with approximate exactness in unextracted samples as is shown in Figs. 2 and 3, and with rough exactness in extracted samples as is shown in Figs. 4 and 5. It is clear from these figures that both cis 4 and Ameripol CB decay more rapidly in unextracted samples than in extracted samples at the temperature used in the present experiment. This phenomenon will be accounted for by the fact that the chemical impurities that remain in unextracted samples will accerelate the scission reaction. The samples shown in Figs. 2, 3, 4, and 5 are replotted in the form of log f(t)/f(0) vs. t, in Figs. 6, 7, 8, and 9, respectively.
    From the slopes of the straight lines in Figs. 6, 7, 8, and 9, the values of k' can be obtained, the functions of T as the Maxwellian decay curve is expressed by equation (1).
    f(t)/f(0)=e-k't (1)
    As such functional dependence of k' on temperature is known to be expressed by the Arhenius equation (2), the values of Eact were obtained for the four samples, the unextracted cis 4, and Ameripol CB, the extracted cis 4 and Ameripol CB.
    k'=Aexp(-Eact/RT) (2)
    In this way the activation energy Eact for the four samples can be calculated, using the plotting in the form of log k' vs. 1/T as shown in Fig. 10.
    The activation energy Eact of the four samples is roughly equal to the value (30±2)kcal/mol as was obtained by A.V. Tobolsky and others with natural rubber being approximately independent of the amounts of cis-1, 4 structure, and of the existence of chemical impurities.
    Various samples of cis 4 and Ameripol CB of different initial cross-link density, i.e., different values of n(0) were prepared. The n(0) values for the samples were determined by measuring the initial stress f(0) at 25% on the equation of state for rubber as shown by equation (3).
    f(0)=n(0)RT[(Lo/Lu)2-(Lu/Lo)] (3)
    Here, Lo/Lu equals to 25% elongation.
    The shapes of the stress relaxation curves of the various samples having different values of n(0) are shown in Fig. 11.
    It is already known that if cleavage occurs randomly at the links of the network chains, the decay of the stress relaxation curves rapidly decrease in n(0).
    According to our experiment shown in Fig. 11, however, the decay of the stress relaxation curves appears to be independent of the initial density of n(0). The fact that f(t)/f(0) is independent of n(0) indicates that cleavage takes place at or adjacent to the network junctures for all cis-1, 4 polybutadiene.
  • 村上 謙吉, 草野 孝衛, 一色 節也, 関口 安貞
    1966 年 15 巻 152 号 p. 317-320
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    EPR was cured with Dicumil peroxide (1), the combination of Dicumil peroxide and p-Quinone-dioxime (2), Dicumil peroxide and Trichloromelamine (3), and Dicumil peroxide and Sulfur (4) at 150°C. Then we observed the mechanism of degradation of those materials by the methods of stress relaxation. It is considered that (1), (2), and (3) caused scission reactions of the links of network chains, but (4) caused scission at both of the network polymer chains and crosslink sites. The degradation owed for its main factor to the amount of peroxides in those materials.
    It is found out that the heat stress relaxation of vulcanizates was accelerated by substances that were soluble in acetone contained in EPR and the curing agents in vulcanizates that had not yet been subjected to reaction. The vulcanizates extracted with benzene relaxed more slowly than those extracted with acetone. Considering the degree of swelling by benzene (larger than by acetone), it seemed that the amount of the curing agents etc. extracted from vulcanizates with benzene and had not yet been subjected to reaction was larger than that extracted with acetone and that resulted in the above phenomena.
    On the other hand, (3) extracted with acetone relaxed more slowly than that extracted with benzene, and this will be accounted for by the fact that Trichloromelamine was soluble in acetone but almost insoluble in benzene.
    The comparison of stress relaxation between commercial EPR and refined EPR revealed that the relaxation or degradation was accelerated when EPR contained some hydrocarbone that was soluble in acetone.
  • 堀野 恒雄, 宮本 喜八郎, 久間 公一, 宗円 寿一
    1966 年 15 巻 152 号 p. 321-326
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    The tensile stress relaxation behavior of two kinds of mixed system, polyvinyl acetate (PVAc)-styrene graft co-polymers prepared by Co60 irradiation on PVAc solutions in styrene monomer, and the mechanical mixtures of PVAc and polystyrene (PS) prepared by n-hexane precipitation from mixed solution of the polymers in benzene, were measured during a period from 30 through 6000sec. under given strains within a limit of linear viscoelasticity at various temperatures ranging from room temperature up to 170°C.
    When the stress relaxation behaviors of the two systems are compared it may be suggested that for the PVAc-styrene grafted system the glass-rubber transition of the PVAc appears clearly, but that of PS slightly, while for the PVAc-PS system the transition of the PVAc appears slightly, but that of PS clearly. This remarkable reverse is attributed to the difference in the degree of mixing of the two components between the systems.
    From the experimental results and previous papers3)∼5) relating to the rheological properties of the mixed systems of two polymer components, are shown in Fig. 8 the schematic representation of temperature dependence of relaxation modulus, the shift factor, and the fractionally free volume for the two polymer components and for 50/50 mixed polymer system, and the schematic model of the mixture of the two polymer components.
  • 吉岡 直範, 中谷 宗嗣, 和田 篤機, 河合 弘迪
    1966 年 15 巻 152 号 p. 327-330
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    The relaxation mechanism of semi-crystalline polymers in the glass-leather transition i.e., the second order transition has not yet so far been understood so well as that of amorphous polymers in the glass-rubber transition is.
    In this paper, the authors have tried to extend the theoretical approaches usually made in explaining the relaxation mechanism of amorphous polymers to the study of that of semi-crystalline polymers, in other words, the existence of crystalline phase has been taken as the potential effects upon the amorphous chain and as a factor reforming the term of entropy elasticity.
    So far as the theoretical consideration is concerned, the authors have used Bueche Model and solved the problem in the light of the theory that accounts for the vibration of a string.
    The relaxation spectra of polyethylene terephthalates having several degrees of crystallinity have been decided from the measurement of complex dynamic tensile modulus on the hypothesis of time-temperature superposition within the glass-leather transition region, and compared with the theoretical results proposed.
  • 中根 平之助, 高橋 康之, 岩柳 茂夫
    1966 年 15 巻 152 号 p. 331-334
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    The dynamic mechanical properties of polytetrafluoroethylene (PTFE) at various frequencies were measured by means of three sorts of vibrations, the torsional free vibration, the bending vibration of rectangular bars freely suspended or fixed on one end, and the longitudinal vibration. The results are compared with those of other authors in the neighborhood of the crystalline transition temperature.1)3)∼9)A broad absorption exists with the low frequencies between the temperatures of the primary absorption (β')1)2) and crystalline transition (about 20∼30°C). The result indicates the necessity of scrutiny of the so called β dispersion region.
    In Figs. 1, 2, 3and 4 are shown the results of measurement of low density sperimen (2.163g/cm3 at 19°C) at various frequencies. In Fig.1, the broad absorption is at about 8°C, which is not in the mechanical data of other authors. The comparison of temperature variation of loss modulus at various frequencies shows that the broad absorption at low frequency is shifted to the higher temperatures with increasing frequency. The relaxation map (Fig. 6) is made by plotting the frequency of maximum loss against the reciprocal absolute temperature in the neighborhood of crystalline transition and the primary dispersion temperatures. This figure is different from the mechanical relaxation map of other authors.1)10) The broad absorption of low density specimen in this figure can be connected with the crystalline dispersion at higher temperatures with increasing frequency. The value of apparent energy of activation of the broad dispersion mechanism was obtained as 27kcal/mole, the value being consistent with that of the primary absorption. It appears in this way that the broad absorption in PTFF comes from the same absorption mechanism as that of the grain-boundary dispersion observed in polyethylene, 11)12) since the broad line component of NMR absorption line does not show narrowing at a temperature above crystalline transition.13)
  • 河合 徹
    1966 年 15 巻 152 号 p. 335-339
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    The elemental mechanism of deformation of crystalline polymers can be classified into the following types:
    (1) deformation of chain molecules in the amorphous state (to some extent, rubbery) (2) rotation of crystallites or lamelae (3) inter-lamellar slip (4) intra-lamellar slip (inter-ribbon slip within the lamelae) (5) unfolding (ridding the chain of the folded form).
    In view of the geometrical complexity in dealing with the deformation of three dimensional spherulites, the deformation of two dimensional spherulites, and samples having the“row structure” have been discussed in terms of the elemental mechanism mentioned above. A comprehensive study of the molecular orientation and crystalline texture in drawn and rolled polyethylene on consecutive stages of heat annealing has enabled a picture of the structural change and reorientation process activated by rubber elastic compression to be outlined. It has been shown that unfolding would not occur so often on elongating the spherulite as usually considered. The inter- and intra-lamellar slips seems to account for the yield in the stress-strain curve of unisotropic films the texture of which is assumed to be of“row structure”which we visualise as consisting of stacks of lamellae. The picture drawn is also consistent with the remarkable anisotropy of the film exhibited by the stress-strain curves. During the annealing process of the drawn and rolled branched polyethylene, the lamellae first begin to rotate around the b axis and keep the molecular orientation within them unaltered until the lamellar become perpendicular to the originally drawn line and the molecular axis inclines to the drawn direction. In the next stage (i.e., at higher temperatures) the compression does not affect the lamellar surfaces orientation but the molecular inclination within them increases until the lamellae become disrupt (the intra-lamellar slip). The lamellae then reform with a distribution in orientation about the axis normal to the film plane. Finally randomisation occurs around the b axis before melting (indicating stability of b axis) and complete disorientation takes place. All the above findings indicate at least qualitatively that deformation occurs in the order of (1)∼(4) mentioned previously. Of course, some of the mechanism is accompanied by some others and the order of the elementary mechanisms to be realized should be dependent on the experimental conditions, especially on temperature. The individuality of the lamellae-requiring an appreciable amount of chain folding even in drawn samples-is nevertheless borne out. The necking occurring in the “cold draw”may be attributable to inter- and intra-lamellar slips.
  • 小田 隆, 坂口 亘弘, 河合 弘迪
    1966 年 15 巻 152 号 p. 340-344
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    In the previous paper, the deformation mechanism of polyethylene spherulite based on the affine deformation was proposed. Individual crystal lamellae were taken as the orientation units within the spherulite, and were allowed to rotate around the a- and b-axes of the crystal by the rotation degree fm and fn, respectively, where m and n were parameters of the ease of the crystal rotations, and f was the functions of deformation ratio of the spherulite and orientation angle of the orientation unit.
    In this paper, the orientation behavior of polyethylene crystallites during the stretch of polyethylenes in bulk at several temperatures ranging from room temperature up to the crystal disordering temperature has been measured by X-ray diffraction technique, and evaluated in terms of the change of orientation factor of the three crystallographic axes.
    Generally, the degree of orientation of crystal a- and c-axes decreases with the increase of the stretching temperature, especially beyond the crystal disordering temperature where the thermal expansion coefficient of a-axis changes abruptly, while that of crystal b-axis does not change sosystematically as a- and c-axes do. This phenomena will be discussed in details in terms of the parameters, m and n of the spherulite deformation mechanism by taking into account the possible deformation mechanisms of the crystal lamellae.
  • 上野 弥, 石川 稔
    1966 年 15 巻 152 号 p. 345-349
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    The force required to tear polymer films was measured at various temperatures, and the rates of the tear of commercial films of cellulose triacetate, poly (ethylene terephthalate), and polycarbonate. One of the arms of the test-piece with a definite length of cut was clamped to a movable crosshead, and the other to a stress transducer. The force for tearing during the tear process was dependent not only upon the type of the polymer but also upon temperature, the rate of the tear, the thickness of the film and its fine structure, and the condition of annealing before the measurement. As the force required to deform the test-piece was found to be negligible in comparison with the tearing force F, the energy for tearing Et is identical with 2F/t where t is the thickness of the specimen. The energy for tearing Et was measured at the rate of tear 0.125cm/sec and 24°C, and the relationship, Et=αtn, was obtained over the range of thickness from 0.01 to 0.2mm where α was defined as the coefficient of tearing being independent of the shape factor of the specimen and the value of n was nearly 0.6 for all the films tested. The coefficient of tearing obtained on assuming n=0.6 was compared with the energy for tensile rupture for several kinds of polymer films, and it was found that the tear strength was not necessarily predictable from the energy for tensile rupture.
    The energy for tearing of cellulose triacetate and poly (ethylene terephthalate) films plotted against the temperature shows maximum value in the neighborhood of the temperature corresponding to the glass transition temperature of these crystalline polymers. For polycarbonate films, however, the energy for tearing steeply decreases in the vicinity of the glass transition temperature without remarkable peak, and the curve shifts toward lower temperature as the rate of the tear decreases. The result of the measurement shows that there are several regions of temperature according to the different mechanisms of tear. The cellulose triacetate film shows stick-slip type of tearing below -50°C, steady from -50 to 70°C, irregular from 70°C to 155°C with the maximum value of energy for tearing, and irregular above 155°C with the energy increasing with temperature. The poly (ethylene terephthalate) film shows steady type of tearing below 10°C, irregular from 10 up to 120°C with the maximum value of energy for tearing, and steady above 120°C.
    The Griffith theory on brittle fracture gives the relationship between the tensile strength and the size of crack in the specimen. The surface energy was obtained from the tensile strength of the specimens containing artificially induced cut of known length in tensile measurement. For the cellulose triacetate film the value of the surface energy at rate of extension 10%/min was found to be 1.6×106ergs/cm2. Though both the value of energy for tearing and the surface energy are in the order of 106ergs/cm2, the former is dependent on the thickness of the specimen and the latter not.
  • 奥村 宗弘, 岸 直行
    1966 年 15 巻 152 号 p. 350-353
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    In our previous paper, 1)2) the mechanism of wear phenomena of fibrous materials was classified into four types under various rubbing conditions. And the relationship between the wear resistance and its mechanical properties was described experimentally as follows;
    Amount of wear loss ∝total frictional force/modulus×tensile strength×elongation
    The purpose of the present paper is to describe quantitatively the mechanism of adhesive wear. Adhesive wear takes place whenever two solid surfaces are in rubbing contact, whether lubricated or not, and remains when all other types of wear are eliminated, so that adhesive wear may be distinguished as the most fundamental of the several types of wear.
    In this analysis the number of contacts of small protuberances in the surface of fiber, I is assumed to be hm/u, where h is the depth of deformation of the surface, u is the distance between the protuberances, and m is a constant.
    (1) The general fomula for the relation between the real area of contact, A, and the load W is obtained as follows;
    A=C·Wm+2·φ/m+2·φ·λ (1)
    where λ=1 as plastic deformation, and λ=3/2 as elastic deformation and φ is a constant in reference to the shape of the protuberance, and C is a constant,
    (2) The general fomula for the relation between the volume of the worn material V and the load W is obtained as follows;
    V=C·WK (2)
    K=φ(ψ-1)+m/2·φ·λ+m (3)
    where ψ is a constant due to the shape of the worn particles.
    (3) In the case of polypropylene monofilaments, K seems to depend upon Young's modulus.
    (4) The temperature dependence of dead weight W/d under which the fibers are broken at a certain NB, shows maxima. In the case of log NB=4, the maxima appear at about 50°C and 100°C. The temperature dependence of W/d for adhesive wear and shaving wear presents similar tendency. Consequently, the temperature dependence of wear resistance in both the types of wear seems to depend upon its polymer properties.
  • 村井 六郎, 森 芳郎
    1966 年 15 巻 152 号 p. 354-359
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    It is the aim of the present paper to consider the steady two-dimensional flow of purely viscous fluid through V-shaped convergent duct. In this study the cylindrical coordinates r, θ and z have been assumed, and the following Reiner-Rivlin Equation has been used as the rheological equation of state for an incompressible purely viscous fluid.
    pij1(II, III)e*ij2(II, III)e*ime*mj (1)
    For the above-mentioned purpose the physical components and the invariants of the rate of strain tensor, and the physical components of stress tensor were calculated for the two dimentional flow of Reiner Rivlin fluid through this duct. The results were integrated into the equation of the motion in terms of stress tensor. From these calculations the following conclusions have been deduced.
    (1) For the flow through the convengent ducts the only non-vanishing invariant of the rate of strain tensor is II, and this invariant depends not only on the non-diagonal components of the rate of strain tensor but also on its diagonal components.
    (2) The flow pattern of the Refiner-Rivlin liquid depends only on the apparent viscosity α1 and not on the cross viscosity α2.
    Based on these conclusions the flow behavior of the two kinds of non-Newtonian liquid has been examined through these ducts. The relations between II and α1 for these liquids are shown by the following equations.
    α1=m(-II)n-1/2 (2) α1=a-c(-II) (3)
    As the results of theoretical examinations having been made the following conclusions have been reached.
    (1) It is tenable that the stream lines of non-Newtonian fluid which obey the Eq. (2) are a group of straight lines that pass through the vertex of V-shape, though it does not follow that the stream lines of the fluid which obey the Eq. (3) are in straight lines.
    (2) For the latter case the θ-component of the fluid velocity must be taken into consideration as well as its γ-component. The following differential equation has been obtained which gives the velocity distribution of non-Newtonian fluid that obeys the Eq. (2) in this duct.
    64n2g4g'+16g4g"'-32(1-n2)g3g'g"+16(1+n2)g2(g')3+4(1+n)g2(g')2g'"-12(1-n)g2g'(g")2
    +16(1-n)2g(g')3g"-4(2-4n+n2)(g')5+n(g')4g"'-n(1-n)(g')3(g")2=0 (4)
    The numerical solution of the Eq. (4) has been obtained by the Runge-Kutta method for some values of n. When the inclination between the two planes of V-shaped duct becomes comparatively small the equation given above will be simplified as given in the following equation.
    4(2n-1)(n-1)gg"-4(1-3n+n2)(g')2+n(n-1)(g")2+ng'g"'=0 (5)
    The analytical solution of the Eq. (5)in the case of n=1/2 is found to run as follows
    g(θ)=A/8[tan(±β)/1+tan2β-tanθ/1+tan2θ+θ-(±β)] (6)
    where A>0 when θ>0, A<0 when θ<0.
  • 磯松 嶺造, 吉田 文昭
    1966 年 15 巻 152 号 p. 360-364
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    The plasticity of clays and pottery bodies is their most obvious property and provides subjects of vital importance in discussing the characteristics and utility of these materials in ceramic industry. Some rheological investigations were performed of Shidare-Kibushi clay, Izushi body, Shigaraki clay and Shinohara body for sample bodies. These sample bodies were prepared always in slip state with a certain volume of water and sodium silicate or sodium carbonate as deflocculants. To decide the amount of thixotropic properties of these samples, a rotational rheometer was devised and constructed by the authors to be used in the present study. In treating these slips, their thixotropic dependency had to be decided in the same way as the viscosity dependency on the moisture contents is determined.
    The following results were obtained:
    (1) The slips prepared from these materials indicated“Plus or minus”value for thixotropy as shown in Fig. 2.
    (2) Remarkable relation was observed to exist between the workability and the thixotropic property in many cases.
    (3) The slips prepared by Shinohara body were observed to have no thixotropic properties in the wide range of water content, and for that reason, these slips had no remarkable workability.
    (4) The relation between the thixotropic properties and the water contents of these slips were classified in some groups, and their rheological measurement was found to be one of the most valuable methods to determine the workability of these materials.
  • 梅屋 薫, 瀬戸 順悦
    1966 年 15 巻 152 号 p. 365-370
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    The dielectric properties of some polymer-powder disperse systems were investigated, using polyvinylacetate (PVAc), poly-methyl-meth-acrylate (PMMA) and poly-buthyl-methacrylate (PBMA) as the polymer components, and calcined non-active alumina, active alumina, silica gel and carbon black as the powder components.
    Bridge method, covering frequency range between 30cps and 5M cps, and temperature range between 10 and 160°C was used as the measuring apparatus, and the following results were obtained.
    (1) The dielectric constants of these disperse systems except the case of carbon black could be computed by Bruggeman's theory which assumed simple mixing. For carbon black powder, on the other hand, the measured dielectric constants were abnormally greater than that of the calculated values by Hanai's theoretical equation suggesting the existence of interfacial polarization. This phenomenon could be explained as the result of particle to particle chain formation.
    (2) Dielectric losses Δε obtained from Cole-Coles plots decreased with increase of the volume fraction of the fillers. The anomaly was also observed in the case of carbon black, indicating the occurence of interfacial polarization and the chain formation.
    (3) The width of the distribution curves of the relaxation time of these disperse systems became broader and the value of β in Cole-Cole's equation decreased remarkably, The tendencies appearing in the Δε and β values were more notable in the case of active fillers than in the case of non-active fillers.
    (4) Under constant temperature the characteristic frequency in which the dielectric losses gave its maximum values was observed to shift a little, no matter whether the absorption at segments in polymer chains were α or β, on the lower side of the frequency ordinates in the case of active fillers, and on the higher side in the case of non-active fillers, than when it was the case with unloaded polymers.
    From the results shown in (2), (3) and (4), are deducible the occurence of new relaxation mechanism corresponding to the particle-dipole interaction in these disperse systems.
    (5) The apparent activation energy calculated by the plots of log fmax vs. 1/T for both mechanisms of the α and β absorption curves was scarcely affected by the addition of filler powders.
  • 小野木 重治, 植木 至朗, 加藤 秀雄
    1966 年 15 巻 152 号 p. 371-376
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    The dynamic viscosity η' and rigidity G' of polystyrene and polypropylene in molten states have been measured by means of a concentric cylinder-type rheometer in the frequency range of about 0.001 to 0.5cps at different temperatures, in order to study the effect of blending on the properties of these substances. The frequency dependence curves of η' and G' at different temperatures can be superposed well according to the usual time-temperature superposition principle without correction for temperature and density. The viscosity data for the polystyrene blends in a wide range of frequency show that the viscosity curves for these blends, differing in their molecular weights from each other, join together at the angular frequencies (ω) higher than about 300, while the rigidity curves for the blends show much difference even at ω=300. This suggests that as a means to distinguish polymers measuring their viscosity alone is not adequate.
    So far as the range of ω is not so high, log (η'/η0) (η0=zero-frequency viscosity) vs. log ω curves for the blends of two components differing only in molecular weight can be superposed into a master curve by shifting the curves for the blends having compositions differing from each other in the horizontal direction by log aM. On the other hand, log G' vs. log ω curves can be superposed by shifting them first horizontally by log aM and then vertically by log cM. The shift factors aM and cM depend not only upon the molecular weight but also upon the molecular weight distribution of the blend. When molecular weight variation of the two components is small, log aM and log cM bear straight-line relationship between log(η020b), where η02 and η0b are respectively the zero-frequency viscosity for the component chosen as the standard and the blends. In the case of polyethylene studied previously2), log cM was zero independent of the composition, and hence the slope of log aM vs. log (η020b) curve was zero. However, in the case of the blends of polystyrene and polypropylene studied here, where the molecular weight variatian of the two components is conspicuously large, the slope of similar straight lines becomes larger. The slopes of the straight lines for log aM and log cM plotted against log (η020b) depend upon the difference between the molecular weights of the two components. Moreover, there can be found the following relation between aM and cM both experimentally and theoretically: cM/aM020b.
  • 坂本 国輔, 片岡 一利, 深沢 義朗, 舟橋 英哉
    1966 年 15 巻 152 号 p. 377-382
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    High density polyethylene (HDPE) has each its distinctive features in the rheological properties according to its manufacturing process. The present work proposes to present a quantitative relationship between its molecular weight distribution and the melt viscoelastic properties for some samples of HDPE.
    The samples have been fractionated by both the elution column technique and the precipitation technique. The number-average, weight-average and Z-average molecular weights have been calculated from the smoothed molecular weight distribution curve for each sample by the method of summation.
    The viscoelastic properties of some series of the commercial HDPE have been measured by means of a concentric cylinder type rheometer at different temperatures (150∼230°C). The angular frequency (ω) ranges from about 10-2 to 50sec-1. The ratio of flow rate at shear stress 106dyne/cm2 to at 105dyne/cm2 (=flow ratio; FR), which gives a good indication of the non-Newtonian property of samples, have been measured by means of a melt indexer type rheometer.
    The results are as follows;
    (1) The linear relationship is found between Mw/Mn and Mz/Mw for only a series of samples made by the same manufacturing process.
    (2) FR is found to be related to Mz/Mw, not to Mw/Mn. log FR=0.137Mz/Mw+1.04
    (3) Dynamic viscosity (η') and dynamic regidity (G') can be superposed according to the temperature-time superposition principle, and shift factors aT from η' and G' are practically the same.
    Agreement with constancy of shift factor for various molecular weights (Mv=5∼10×104) and distributions is good, and the apparent activation energy (ΔHa) calculated from the shift factor is 6-7kcal/mol. ΔHa of copolymer is also of the same value.
    (4) Master curves also are constructed with respect to the molecular weight for measurements of η' and G' versus ω for only those samples in which Mz/Mw are equal to each other.
    Shift factors aM from η' and G' are the same.
    The relationship must also be right in the steady flow viscosity, and confirms that HDPE with the same Mz/Mw have equal FR.
    (5) The relationship between η0 and Mw is effected by the molecular weight distribution.
    log η0=3.5log Mw+log (Mz/Mw)-12.7
  • 藤本 邦彦, 猪俣 亥一
    1966 年 15 巻 152 号 p. 383-388
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    It is concluded from NMR, X-ray and other experimental results, that the rubber molecules of vulcanized fillers-in form three different phases, the unmotional, the collectively cross-linked, and the micro-Brownian motional, phase. And it is considered from the view point of molecular mobility that vulcanizates used as fillers-in form heterogenious structure. In the present experiment, we mixed a little amount of ZnO (needle-shaped crystals) in unvulcanized fillers-in, and made X-ray investigations of the orientation of ZnO atoms and the rubber crystals generated in the process of extension.
    The results are as follows:
    (1) The rubber molecules in the highly motional phase are quickly orientated by extension, but those of the unmotional and collectively cross-linked phases are slowly orientated to show non linear movement.
    (2) Non linear movement of the unmotional phase is influenced greatly by the type of crosslink with sulfur; the less the number of sulfur atom in the sulfide cross-linkages, the less non linear character is.
    This is attributed to the restraint of the movement of the rubber molecules in the unmotional phase due to the sulfide cross-linkages.
  • 小野木 重治, 浅田 忠裕, 福井 芳治, 藤沢 丈夫
    1966 年 15 巻 152 号 p. 389-394
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
    An equipment has been designed to provide a record of the birefringence change accompanying a stress-strain measurement or a stress relaxation measurement. The equipment consists of Instron type tensile tester and an optical system to measure the birefringence which has been designed to be easily mounted on or removed from the tensile tester. The optical system has a conventional arrangement consisting of a light source, filter, crossed polaroids and so on, and the birefringence can be recorded continuously by the intensity method with a photomultiplier.
    The change in the birefringence with time during the stress relaxation has been measured for low density polyethylene with this equipment. The birefringence vs. time curves at different strain levels show a similar shape, being consistent with the data obtained by Strella et al. There can be found straight-line relationship between the birefringence and the strain at any time during the relaxation under the strain level lower than about 5%. The time dependence of the strain-optical coefficient depends highly upon temperature, and a transition of the strain-optical coefficient can be observed at the temperature region covered by this experiment. By shifting the curves at different temperatures horizontally, a single composite curve was obtained. The annealed and quenched films of low density polyethylene show definitely different birefringence, but the temperature dependence of the shift factor log aT for these films gives the same straight line when it is plotted against reciprocal absolute temperature. This can be understood qualitatively, at least, on the basis that the relaxation mechanism which is responsible for the birefringence of both the annealed and quenched polyethylene films in such a temperature region is the same. The optical relaxation spectrum for the annealed and quenched polyethylene has been obtained by the first approximation method. The longest relaxation time for the annealed material is almost two decades longer than that for the quenched one.
  • 1966 年 15 巻 152 号 p. 395-400
    発行日: 1966/05/15
    公開日: 2009/08/20
    ジャーナル フリー
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