The factorable BKZ constitutive models including that of the Doi-Edwards tube model theory is not capable of describing steady shear flow behavior at constant stress. The existence of the steady shear involving large strains at very small stresses requires that the damping function must always remain unity for very slow deformation. If a steady shear flow is attained in the creep at high stresses, the damping function may not decrease indefinitely with increasing strain but must tend to approach a finite value η(γ)/η₀ where η(γ) is the steady shear viscosity and η₀ is the zero-shear viscosity. These features can be introduced to the model if an effective strain, that does not increase indefinitely in the case of gradually increasing strain, is used in the place of the strain in the damping function. The effective strain may be defined by counting only the strain applied to the material not earlier than t-2τ_A where t is the current time and τ_A is an average relaxation time defined as the product of viscosity and the steady shear compliance. With this modification of the model the values of steady shear viscosity evaluated for the creep and for the flow of fixed rate of shear are consistent with each other up to a moderate rate of shear.

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Dispersion state of chopped glass fibers (GF) filled in a polypropylene (PP) before and after application of shear flow were studied by means of direct observation of the glass fibers and the dynamic viscoelasticity measurement of melt samples. Dispersion state of the fibers in PP/GF samples varies with the fiber length and the compatibility of binder polymer with the matrix polymer. The difference of the state of filled fibers in the matrix affects significantly the dynamic viscoelasticity of the melt samples.

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Damping functions in uniaxial, biaxial, planar extensions and shear deformation were calculated based on the Doi-Edwards theory. Planar extensional damping function has two components, h_p1 and h_p2 where the subscripts 1 and 2 stand for the stretching and restricting directions, respectively. Compared with the rigorous calculation, independent alignment approximation (IAA) works well except for h_p2. In h_p2, large difference between IAA and rigorous calculation appears. The calculated damping functions becomes approximately a universal function of the first strain invariant I except for h_p2. On the other hand, compared at the same I, the experimental damping functions slightly deviate from each other. This deviation can be related to a difference in the magnitude of the second strain invariant II in different deformation fields.

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Extruded blown films of high density polyethylene contain oriented crystalline lamella normal to the extrusion direction. In the elongation perpendicular to the extrusion direction (TD) at -110°C-40°C, the stress suddenly dropped when the film arrived at the yield point and the necking propagated steadily under a constant stress value. TD deformation mechanism is explained by unfolding from one part of the lamellae as proposed by Horio and Kobayashi (silk hat model). On the contrary, in the elongation parallel to the extrusion direction (MD), deformation mechanism is complex and we have proposed an unfolding model. In the MD, stress did not drop even after the yield point, and it maintained a constant value. Consequently the film was uniformly elongated by appearance, but followed by a partial necking. From optical and scanning electron microscopic observations, the lamellae were bended, twisted, or rotated by the stress, and the long axes of lamellae (b-axis) were changed to the drawing direction and the film was elongated by unfolding same as TD elongation.

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The degree of equilibrium swelling and the dynamic Young's modulus for end-linked poly(dimethylsiloxane) networks in theta solvent are investigated as a function of polymer concentration at preparation. The experimental results agree well with the predictions of modified affine model, while they are not satisfactorily reproduced by the c* theorem.

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An azeotropic copolymer of styrene and acrylonitrile was studied with its gelation process via the cyclodiborazane formation between thexylborane (TB) and the cyano groups of the copolymer in 2-methoxyethyl ether solution. The concentrations of TB, cyano groups, and iminoborane were in situ determined by infrared spectroscopy. In addition, the number density of cross-links, i.e., the concentration of cyclodiborazane was quantitatively estimated after the treatment with methanol, which reacts with the B-H groups of TB and iminoborane without decomposition of cyclodiborazane. The number of cross-links was found to increase with reaction time, reaching about 3 per chain at the gel point for the copolymer used in this study.

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We measured the dynamic viscoelastic behavior of poly(methylmethacrylate) (PMMA)/polystyrene(PS)(8:2) blend melts.The volume average radius of droplets of dispersed phase was estimated from transmission electron microscopy(TEM) micrographs of the blend. We determined the interfacial tension by comparison of the dynamic data with the Palierne theory. The interfacial tension thus determined agrees fairly well with the values obtained by other methods.

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We present results of dynamic viscoelastic measurements on toluene solutions of telechelic polybutadiene-magnesium ionomer, as one of model systems suitable for a study on structure and dynamics of associating polymers over a wide range of temperature T and polymer concentration C. T dependence of the viscosity is found to be expressed as the product of two contributions, one from local segmental motion and the other from the dissociation-association process of the end ionic groups with the activation energy, E_a≅77kJ/mol.

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The relaxation times of local motion for five kinds of polymers: cis-polyisoprene (cis-PI), polystyrene (PS), poly (α-methylstyrene)(PαMS), syndiotactic-poly (methyl methacrylate) (s-PMMA), and poly (N-vinylcarbazole) (PVCz) were measured in the Θ solvents by the fluorescence depolarization technique. The viscosity reduced relaxation time T_m/η was in the following order with the activation energy in the same order: cis-PI < PS < PαMS < PVCz < s-PMMA. The relaxation time and the activation energy depend on whether the polymer is either mono-substituted or di-substituted, the bulkiness of the substituents, and also the stereoregularity. It was found that T_g, is closely correlated with the local chain mobility obtained in dilute solution.

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Stress relaxation behavior of poly ( N-isopropylacrylamide)(PNIPA) gels in the collapsed state was investigated. The normalized stress reduction ( Δσ_eo/σ_eo) decreased with increasing temperature. The higher value of Δσ_eo/σ_eo was observed for the gels prepared from the solution with high monomer concentration ( c₀ ). The relaxation time determined in the long time region of the stress relaxation curve ( τ_σ) become shorter as temperature increases. The longest relaxation time τ_σ decreased with increasing c₀. It was also shown that the diffusion constant of the network in the collapsed state is much smaller compared with that in the swollen state.

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Viscoelastic fluids sometimes possess a dominant elastic stress relative to the viscous stress and in this case the viscous contribution can be neglected and the fluid is thought to be as an elastic fluid. In the present paper the author extends the theorem of Bernoulli for perfect fluid to a generalized theorem of Bernoulli for the elastic fluid in which a term of elastic stress is added to the dynamic pressure term, the static pressure term and the gravitational term. Based on this equation some flow problems are examined; the contraction of the flow in a reservoir discharging a elastic fluid, the pressure of the flow through a converging and diverging channel, the abnormal pressure rise just downstream of the inlet of a pipe flow, the diameter of the jet issuing from an orifice to the atmosphere and a falling liquid column in the gravitational field. It is shown that the results agree at least qualitatively with experimental data so far obtained.

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We studied the effect of ultrahigh molecular weight (UHMW) polymer on the strain-hardening in uniaxial elongation using PMMA varying UHMW content. These samples were homogeneously blended by solvent casting method. The relation between UHMW components and uniaxial elongational viscosity are discussed.

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We report here effects of microdomain structures on the mechanical properties of polystyrene-block-polyethylenebutylene-block-polystyrene (SEBS) triblock copolymers. Microdomain structures were analyzed by the small-angle X-ray scattering technique and the mechanical properties were evaluated by the viscoelastic measurements. Two kinds of SEBS samples were used, which have similar molecular weights but different compositions. One of them having φ_ps (volume fraction of polystyrene) of 0.16 underwent transition from spherical to cylindrical morphology when an as-cast film from its heptane/methylene chloride (1/1 by volume) solution was annealed at 150°C which is above the glass transition temperature of PS (polystyrene). Another SEBS sample having φ_ps = 0.54 exhibited lamellar ordering when an as-cast film was annealed at 150°C According to these structural transformation, mechanical properties changed. Especially, the storage moduli of the annealed films around 25°C increased twice as big as the as-cast films. This result correlates well with generation and development of continuity of the glassy PS microdomains in SEBS16 and SEBS53, respectively.

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Morphology and brittle temperatures of seven Polypropylene(PP)/Ethylene-Propylene rubber (EPR) blends were investigated. Sizes and interparticle distances for dispersed EPR particles were measured. EPR concentrations in PP matrix phases were also evaluated. Based on these results and brittle temperatures for the blends, molecular mechanism of brittleductile transition for PP/EPR blend was discussed.

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Rheological properties and structure of the lamellar phase formed in AOT/water binary systems have been investigated using dynamic viscoelastic measurements and small angle X-ray scattering (SAXS). The lamellar repeat distance L is linearly dependent on the water/AOT weight fraction ratio Φ, suggesting that the thickness of AOT bilayer l_A and the surface area per AOT molecule S_A is independent of AOT concentration. From the slope and intercept of plots of L against Φ, the values of l_A, density of AOT bilayer ρ_A, and S_A can be obtained respectively as 17.9Å, 1.28 g/cm³, and 64.5Ų. These values are consistent with the AOT molecular formula. The values of storage modulus G′ and loss modulus G″ of the AOT/water bilayer systems are almost constant over wide range of frequency, and G′ is always higher than G″ for all the samples. And G′ increases with increasing AOT concentration. These fact suggest that the lamellar structure is three-dimensionally extended over the systems.

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Poly (ethylene terephthalate) [PET]/ polyethylene [PE] blend polymer solution using methylene chloride as solvent was flash-spun into fibers. The tensile strength as well as the initial modulus and the maximum point modulus in the differential modulus-stress curves decreased with the increase in content of PET. The wide-angle X-ray diffraction photographs revealed that PE crystallized, although PET showed hollow pattern. These result suggest that PET component moves to the dilute phase of PE when phase separation occurred in the course of spinning, then the fibers are formed independently with respect to each component during the flash spinning. PET may not be able to crystallize due to low temperature during the flash spinning, while PE can be flash-spun into fibers with crystallization.

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The keratinization process of wool fiber in follicle was discussed on the orientation of microfibril to the direction of fiber axis considering the driving force for the appearance of Kerr effect. The deference of oxidation-reduction potential values between both edges of the follicle region being in process of keratinization was in the order of 250 mV by the application of the Nernst equation. The electric potential gradient dψ/dx calculated by considering the thickness of keratinization region was about 25 V/cm which corresponded to the value required for the high speed electric spinning of gelatin thread in the model experiment. It was also confirmed that the appeared potential gradient could deform the cortical cell the spindle shape if the relative electric conductivity of the inner follicle solution surrounding cortical cells is lower than that of the cells. For the discussion on the overall keratinization process the speed of electron transfer across the intercellular region of wool fiber was compared with that across the kerateine or inter cellular material immobilized in an artificial membrane.

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For 20 spieces of polymer crystals, a correlation between the crystallite modulus along the chain axis and the durability of crystallinity against electron irradiation was examined. As for the modulus (Ec), the observed and/or theoretically calculated values were cited from literature. As a measure of the durability, the total end-point dose (TEPD) for each polymer crystal, namely the electron irradiation dose necessary for complete disappearance of crystalline reflections in the selected-area electron diffraction pattern, was estimated experimentally for 200kV electrons or cited from literature. It was suggested that there exists a weak, but some correlation in a plot of Ec against the logarism of TEPD, although the number of data points was not enough.

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Rodlike and semiflexible polymers, most of which are capable of forming lyotropic liquid crystals at high concentrations, are referred to as non-flexible polymers. They show some remarkable differences in dynamic properties from flexible polymers, e. g., remarkable concentration and molecular weight dependences of viscosity; no simple power law exists. This paper presents our recent effort toward slow global dynamics such as diffusion and viscosity mainly from theoretical aspects. Indeed new theories are developed, where a new model, the fuzzy cylinder model, has been introduced to replace the wormlike cylinder to derive expressions for diffusion and viscosity, which contain only one adjustable parameter, the similitude ratio λ*. When both entanglement and hydrodynamic interacations are considered, they are used successfully to data for non-flexible polymers with the persistence length q in the range between 10 and 200 nm, but limited to Kuhn statistical segment number below 20. However the theory is not satisfactory for dielectric dispersions, which contain intramolecular motional modes neglected in the above theoretical development.

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