Motion of a rigid cylindrical particle in narrow channel flow

Motion of a rigid cylindrical particle in narrow channel flowMasako SugiharaSeki

Citation: Journal of Rheology (1978-present) 39, 791 (1995); doi: 10.1122/1.550658 View online: http://dx.doi.org/10.1122/1.550658 View Table of Contents: http://scitation.aip.org/content/sor/journal/jor2/39/4?ver=pdfcov Published by the The Society of Rheology Articles you may be interested in Oscillating motions of neutrally buoyant particle and red blood cell in Poiseuille flow in a narrow channel Phys. Fluids 26, 041904 (2014); 10.1063/1.4872023 Research on transient flow resistance of two-phase in narrow rectangular channel under rolling motions AIP Conf. Proc. 1547, 21 (2013); 10.1063/1.4816847 Acoustic wave motion along a narrow cylindrical duct in the presence of an axial mean flow and temperaturegradient J. Acoust. Soc. Am. 107, 1859 (2000); 10.1121/1.428466 Osmotically Driven Flow in Narrow Channels Trans. Soc. Rheol. 20, 23 (1976); 10.1122/1.549402 The Motion of Cylindrical Particles in Viscous Flow J. Appl. Phys. 10, 711 (1939); 10.1063/1.1707254

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Abstracts of manuscripts appearing inNihon Rheoroji Gakkaishi

(Journal of the Society of Rheology, Japan)Volume 22, 1994

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788 JAPANESE ABSTRACTS

Thin filament equations. Part 1. Equations in simplestform and their solutions

Susumu Kase

Department ofPolymer Science and Engineering, Kyoto Institute ofTechnology, Sakyoku Matsugasaki, Kyoto 606, Japan

Synopsis

The present paper is the first of a series of manuscripts which are devoted to extensive discussion

of thin filament equations, i.e., the simultaneous partial differential equations governing the

continuous drawing and transient stretching of liquids taking the shape of thin filaments. This paperexclusively deals with thin filament equations in their simplest form, namely the equations

governing the isothermal melt spinning of Newtonian fluids. Subjects covered are (l ) formulation

of the equations, (2) solution for the steady state spinning, (3) perturbation equations around the

steady state spinning, (4) analytical transient solution of the perturbation equations, (5) numericaltransient solution of perturbation equations for the constant take-up speed spin line, (6) frequency

response transfer functions, (7) stability of spin line, (8) numerical solution of the nonlinear thin

filament equations simulating the draw resonance oscillation, (9) analysis of spin line transients inLagrangian (T,T') coordinates, (10) equivalence to the classical wave equation, and (II) analysis ofone-shot transient stretching of thin filaments in Lagrangian (T, >.) coordinates.

Pages 5-17


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JAPANESE ABSTRACTS

Wall friction and slip of highly filled suspension

Hachiro Nakamaru

Department of Chemical Engineering, Hiroshima University,Kagamiyama 1-4-1, Higashihiroshima City 724, Japan

Yosio Sunada

789

Taiyo Oil Co., Ltd., Kikumacho, Ochigun, Ehime Pret 799-23, Japan

Yoichi Nagase

Department of Chemical Engineering, Hiroshima University,Kagamiyama 1-4-1, Higashihiroshima City 724, Japan and Taiyo Oil

Co., Ltd., Kikumacho, Ochigun, Ehime Pref. 799-23, Japan

Synopsis

Failure and slip on the wall in the straight pipe were studied for highly filled suspension (HSF) ofkaolin-water including additives. To visualize the deformation of HFS, red mark lines were inserted.Complete slip between HSF and solid wall was observed. It was confirmed that Coulomb's criterionwas valid for the failure between flat wall and HSF, and was different from that in the bulksuspension. The equilibrium equation between the failure shear stress at the wall and the extrusivepressure by piston was derived on the assumption that the extrusive pressure was equal to the axialstress at the wall. The prediction, which showed the variation of extrusive pressure along the axialdirection, was in good agreement with the experimental result. It was also shown that the increaseof wall stress with slip flow velocity after the failure was equal to the superposed friction resistancesof motion to the static failure stress.

Pages 18-22


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Slip analysis of highly filled suspension in the coneextruder

Hachiro Nakamaru


Masami Kuwai

Sakai Kagakukyogo Co., Ltd., Ebisujima 5-1, Sakai City 590, Japan

Yoichi Nagase


Synopsis

Following the foregoing work. extrusions in the cone were studied for highly filled suspension(HSF) of the kaolin-water system including additive. By the visualization, the slip line was observedwithin the HFS, instead of the wall slip reported in the previous paper. In the cone, only one slip linewas observed with a fixed boundary condition. Therefore, the direct analysis for slip can be applieddifferent from the usual slip line analysis. The ordinary differential equations for slip angle, Tf, and

mean principal stress, Urn ' were solved directly with the boundary condition as function of radius,r. Observed slip lines agreed well with the theory. The extrusive pressure calculated by integratingthe stress component of the extruding direction along the slip line also agreed well with thecorresponding piston load. Thus, the present method was useful.

Pages 23-26


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JAPANESE ABSTRACTS 791

Motion of a rigid cylindrical particle in narrow channel:flow

Masako Sugihara-Seki

National Cardiovascular Center Research Institute, Suita, Osaka 565,Japan

Synopsis

The motion of a rigid cylindrical particle freely suspended in a two-dimensional channel flow isstudied numerically at low Reynolds numbers. The particle is assumed to be an elliptic cylinder ora doublet consisting of two equal-sized circular cylinders held in rigid contact. The Stokes equationsfor the suspending fluid are numerically solved with a finite element method for an estimate of the

longitudinal, lateral, and angular velocities of the particle at conditions of zero force and zero torqueon the particle. Using the velocities obtained, the trajectories of the particle are determined forvarious initial configurations. The particle is found either to tumble or to oscillate cyclically,depending on the particle size/channel width ratio, particle shapes, and initial conditions. In the

former case, both of the elliptic cylinders and doublets rotate continuously in one direction duringone period, which is well approximated by so-called Jeffery's solutions for a spheroid in unboundedsimple shear flow. In the latter case, the particle oscillates in rotation, accompanied by a periodicsidewise drift. The sidewise drift of doublets is about the center plane of the channel, while themean lateral position of elliptic cylinders is either on or off the center plane.

Pages 27-31

Rheological properties of magnetic paints containingbarium-ferrite fine particles with various aspect ratios

Masuo Kudo, Kenji Iwakura, and Toru Masuko

Department of Materials Science and Engineering, Yamagata University,Yonezawa 992, Japan

Synopsis

Static flow properties of magnetic paints containing hexagonal shaped barium-ferrite fine panicleshave been investigated in terms of their diameter/thickness aspect ratio. The Ba-ferrite paintsshowed typical pseudoplastic flow behaviors with different yield stresses. The flow curves weredivided into three types of flow components using Kuin equation as follows: (L) yield stress part,(2) Newtonian flow pan, (3) viscoelastic deformation of floes with stress relaxation. Each flowcurve for the Ba-ferrite paint could be well-fitted to the theoretical trace by the Kuin equation, andfour kinds of rheological parameters were obtained from those procedures. We found that suchparameters except for the Newtonian viscosity increase with increasing particle aspect ratio orpanicle specific surface area. This implies that the rheological properties of Ba-ferrite paints arestrongly governed by the panicle interaction forces associated with particle characteristics.

Pages 32-36


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Effects of PVA and inorganic surface coating on theviscous flow and dispersion properties of monodispersed

silica microspheres

Hideyuki Komaki and Mamoru Senna

Faculty of Science and Technology, Keio University, Hiyoshi, Yokohama223, Japan

Synopsis

Steady viscous flow and dispersion properties of aqueous suspensions containing monodispersedsilica microspheres of 0.9 tLm were studied with special emphasis on the effect of PYA addition asa function of pH. Larger amount of PYA adsorption, observed at lower pH, always favored betterdispersion and lower apparent viscosity. An apparent median particle size of the floes in the stagnantsuspension was mainly dominated by electrostatic repulsion and accordingly by pH. While the zetapotential was determined solely by the surface species of the particles coated with either Alz0 3 orzrOz, silica substrate was suspected to affect the adsorption behavior of PYA on the silica particles,coated particularly by Alz0 3.

Pages 37-44

Correlation between flow properties of silica-PVAaqueous slurries and spray-dried granules

Toshihiro Ishimori

Division of Research and Development, KOSE, Co., 1-81-4 Azusawa,Itabashi-ku, Tokyo 174, Japan

Mamoru Senna

Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi,Kouhoku-ku, Yokohama-city, Kanagawa 223, Japan

Synopsis

The correlation between rheological behavior of a slurry, composed of silica microspheres and poly(vinylalcohol) (PYA). and microstructure and also the disintegration behavior of spray-driedgranules were studied. Pseudoplastic flow behavior was analyzed under the Bingham approximationto obtain the Bingham yield value, TB, plastic viscosity, 77pl' and bulkiness of the flow unit, CF P .

CFP is the ratio of the effective volume fraction of floes, rPp, to that of dry solid, r/Jp. Thedispersion of silica in the slurries was dominated by PYA adsorption at low pH and the electrostaticrepulsion at high pH. The granules prepared from the slurry at pH = 7 had the smallest apparentdensity and disintegrated under the smallest applied load. It is concluded that the microstructure anddisintegration behavior of the granules are greatly affected by pH values at which the slurries areprepared. in spite of the similar flow behavior.

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Viscoelasticity of CTAB:NaSallW detergent micelles. Saltand temperature effects

Mitsue Kuwahara and Norio Nemoto

Institute for Chemical Research, Kyoto University, Uji, Kyoto 611, Japan

Taisei Hirayama

Rigaku Corporation, Shinjuku, Tokyo 160, Japan

Kunihiro Osaki


Synopsis

Dynamic viscoelasticity is measured for threadlike micelles from cetyltrimethyl-ammoniumbromide (CTAB) in aqueous sodium salicylate (NaSal) solutions at temperatures T = 25, 33, 40,and 50°C. The CTAB concentration of the solutions is fixed at CD = 0.01 M and a ratio of NaSal

concentration Cs to CD' CsiCD, is varied from I to 41. Effects of both Cs/CD and T on frequencydependence of storage and loss shear moduli, G' (w) and Gil(w), are described in this paper in detail.Characteristic features of this micelle system may be summarized as (I) at 25 and 33°C, the steady

viscosity 17 and the mechanical relaxation time 7M both show a minimum at CS/C D ~ 4 that isfollowed by a maximum at CSICD - 10 as CSIC D increases. (2) The 17 and 7M monotonicallydecrease with increasing T in the range of CS/C D from I to 20, but the maximum itself graduallydisappears a" T increases. (3) The steady state compliance J e is independent of T and decreases atlower CS/C D . A rapid increase in J; is observed at higher T and CSIC D ends. (4) An additionalviscoelastic relaxation process is observed at the high frequency side. This mode appears in thesame w range independent of the salt concentration and exhibits the T dependence such as a type

of the local friction factor, TJsl T. The discussion is mainly devoted to the applicability of a coupleof models proposed so far.

Pages 57-62


07:24:22


Behavior of laminar boundary layer with shearthickening-thinning characteristics of non-Newtonian

flows

Hiroshi Yamaguchi

Department of Mechanical Engineering, Doshisha University, KarasumaImadegawa, Kyoto 602, Japan

Synopsis

Non-Newtonian characteristics of boundary layer flow passing a flat external surface with zeroincident angle were studied using Phan-Thien Tanner (PTT) type constitutive equation with thenetwork theory. Consideration is given to the shear thickening and the shear thickening-thinningcharacteristics of fluid in the flow problem. The Von Karman integral equation is solved numericallyin order to obtain the boundary layer thickness and associated friction coefficient. Two importantparameters in the network theory, the segment number and chain slippage parameter, are discussedto investigate their effects on the boundary layer characteristics. The calculated results indicate thatthere are large jumps of boundary layer thickness at the leading edge of the plate for small slip

parameters when the effect of normal stress is not included in the calculation. On the contrary, thejumps are eliminated, particularly for smaller Reynolds number, with the inclusion of the effect ofnormal stress.

Pages 63-67


07:24:22


Normal force generated in the flow of viscoelastic fluidsbetween two rollers rotating at relatively different

speeds

Tatsuo Sekino

Graduate School of Science and Technology, Niigata University, 2-no-choIkarashi, Niigata 950-21, Japan

Tomiichi Hasegawa and Takatsune Narumi

Faculty ofEngineering, Niigata University, 2-no-cho Iharashi, Niigata950-21, Japan

Synopsis

Normal force is measured which is generated in the flow between two rollers, one rotating and theother fixed. Aqueous glycerin solutions are used as Newtonian fluids, and dilute solutions ofpolyethylene oxide (PEO) and polyacrylamide (Separan) are used as viscoelastic fluids atconcentrations of 50-1000 ppm in weight. The force measured for viscoelastic fluids is larger thanthat for Newtonian fluids. The normal force for Newtonian fluids is evaluated by applying theCameron's theory with the Reynolds equation and the half Sommerfeld condition. It is found thatthe calculated force agrees well with the experimental result. The normal force for viscoelasticfluids is predicted using the same assumptions as for Newtonian fluids except the constitutiveequation of Coleman-Noll. The predicted expression is in good agreement with the presentexperimental result for dilute PEO solutions but roughly agree with the data for nondilute PEO andSeparan solutions.

Pages 68-74

Flow behavior of concentrated suspensions

Yasufumi Otsubo

Department of Image Science, Faculty ofEngineering, Chiba University,Yayoi-cho 1-33, Inage-hu, Chiba-shi 263, Japan

Synopsis

Concentrated suspensions of noninteracting particles show dilatancy at high shear rates, whereasflocculated suspensions are generally pseudoplastic over a wide range of shear rates. The effects ofcolloidal attraction between particles on the dilatant flow are examined for aqueous suspensions ofzinc sulfide (ZnS). The particle-particle interactions are controlled by surface treatment of particlesand addition of surfactant. The steady-flow properties were measured for suspensions atconcentrations from 40% to 55% by volume and the degree of colloidal stability was evaluated bythe particle concentration in the sediment. With decreasing particle concentration in the sediment,i.e., with increasing colloidal interactions, the dilatant behavior becomes less obvious. For theappearance of dilatant flow, the floes must be broken down to primary particles in shear fields. Thehydrodynamic forces required to break the floes were calculated.


07:24:22


Mechanical properties of guttapercha point

Toshiaki Dobashi, Susumu Tanaka, and Akio Sakanishi

Department of Biological and Chemical Engineering, Faculty ofEngineering, Gunma University, Kiryu, Gunma 376, Japan

Nobuyuki Hattori, Izumi Takenaka, and Kazuo Hirota

Research and Development Department, G-C Dental Industrial Corp., 761 Hasunumacho, Itabashi-hu, Tokyo 174, Japan

Synopsis

Stress-strain curve was measured for guttapercha point, a dental material, using a tensile testinginstrument. Effective strain was calculated with a simple correction based on Hooke's law. All theobserved stress-strain curves were in substantial agreement at a low strain range, independent ofthe initial length. Young's modulus was determined to be 5.6X 109 dyn/crrr' from the initial slope ofthe curve in dry state at the humidity of 49%-68% at 24°C. Both the yield stress and the yieldstrain decreased linearly with increasing initial length. In wet state at 20°C in Ringer's solution, thestress-strain curve was remarkably nonlinear and the yield strain in wet state was about twice aslarge as that in dry state. Increasing the temperature to 37 DC at physiological state, the yield stressdecreased to a third as large as that at 20 "C. Guttapercha plate showed an anisotropic stress-strainbehavior depending upon the direction of extensions in the manufacturing process, The Young'smoduli for the sample stretched in the longitudinal and lateral direction were 8.3 and l3.3X109

dynlcm2, respectively. Both of the moduli increased with the content of the filler in accordance withthe theory by Guth. The larger values of the moduli in comparison with that of guttapercha pointseem to be due to the difference in molecular orientation caused in the manufacturing process.

Pages 80-85

Flow of liquid dairy foods in small gaps

Hideo Shidara

Morinaga Milk Industry Co. Ltd., Engineering Research Center, 4-515Tateno Higashiyamato City, Tokyo 207, Japan

Morton M. Denn

Department of Chemical Engineering, University of California atBerkeley, Berkeley, California 94720

Synopsis

The viscosities of liquid dairy foods were measured in a slit rheometer with gap spacings as smallas 34 p.m. Large positive deviations from the true flow curve and an approach to a constant stresswere observed below a critical rate in each material studied. This behavior is indicative of probableagglomeration and "bridging," most likely in the entrance to the dye. In all cases mean particlesizes were an order of magnitude smaller than the slit.


07:24:22


Nonequilibrium heterogeneous structures in amorphouspoly(ethylene terephthalate) glasses

Kuniyoshi Itoyama

Toba National College of Maritime Technology, 1-1, Ikegami-cho, TobaCity, Mie 517, Japan

Synopsis

The effect of physical aging on excess enthalpy has been investigated for the amorphouspoly(ethylene terephthalate) (PET) glasses prepared by both means of quenching the melt intoliquid nitrogen (type I) and casting the melt on a rotating metallic roller at 10 DC (type II). The

relaxation toward the equilibrium of the enthalpy, monitored by a differential scanning calorimeter(DSC), is described by a relaxation fraction of the excess enthalpy ¢ as a function of aging time andtemperature. On the physical aging in the two PET samples, a plot of ¢ against log fa gives anessentially straight line for the PET I sample, and the plot for the PET II sample can be divided intothree distinct regimes with increasing log fa: a short-time regime where ¢ linearly decreases with

log fa' a middle-time regime where ¢ takes an almost constant value, and a long-time regimeshowing a secondary decrease in ¢. When the PET II is aged at 60-70 DC, two endothermic peaksin a DSC scan arise in the middle and the longer regimes of the aging time. The peak positions aswell as their magnitudes considerably vary with the aging time. These results for the PET II suggestthat polymer-chain rearrangement during the physical aging process is a dissipative process whichresults in nonhomogeneous glassy structures consisting of low- and high-enthalpy regions.

Pages 9()-97


07:24:22


Entry flow of dilute fiber suspensions through a tubularcontraction

Kunji Chiba

Faculty of Education, Shiga University, Otsu, 520 Shiga, Japan

Tetsuya Yamamoto and Kiyoji Nakamura

Department ofMechanical Engineering, Osaka University, Suita, 565Osaka, Japan

Synopsis

Finite difference solutions and observations have been presented for the flow of dilute suspensionsof rigid, high aspect-ratio fibers in Newtonian fluids through a 4: I tubular contraction. The effect offlexibility of particles on the flow fields is also discussed from comparison of their configuration and

entry flow patterns between rigid fiber suspensions and flexible molecule systems. For rigid fibersuspensions, the main flow patterns become nearly conical and the comer vortex length is almostindependent of flow rate under the Reynolds number less than 0.1. On the other hand, for flexiblemolecule systems, the comer vortex rapidly grows with an increase in flow rate and the wine-glassshaped flow with the convex vortex boundary also presents a striking contrast to the fibersuspension flows. Therefore, full discussion of the change in fiber or molecule configuration duringflow seems most significant to understand the energy flow kinematics. Further, the computed stressfields clearly indicate that entry flows of rigid fiber suspensions can also exhibit the stress reliefphenomenon due to vortex enhancement, which was observed for polymer liquids: the increase inthe normal stress difference around the center line near the entrance of the contraction can besuppressed.

Pages 98-105


07:24:22


Dynamics of a semiflexible polymer poly(n-hexylisocyanate) in isotropic solution. 1. Zero shear viscosity

Atsuyuki Ohshima, Hiroyuki Kudo, Takahiro Sato, and Akio Teramoto

Department of Macromolecular Science, Osaka University, Toyonaka,Osaka 560, Japan

Synopsis

Zero shear viscosities TJo were measured for toluene solutions of ten fractionated poly(n-hexylisocyanate) (PHIC) samples from dilute regime to concentrated isotropic regime. PHIC is asemiflexible polymer with the persistance length q = 37 nm in toluene. For six PHIC samples with

the molecular weight less than 14X 104• the dependence of TJo on the polymer concentration c did

not obey any power law. while for the higher molecular weight samples. no was almost proportionalto c 3

.2 in a high c region. At fixed c, TJo was almost proportional to M~ in a high M v region (M v :

viscosity average molecular weight). These concentration and molecular weight dependences aredistinct from not only those for flexible polymer solutions but also those for much stiffer polymersolutions [e.g .• schizophyllan (q = 200 nm) and xanthan (q = 120 nm)]. The results of 7Jo forPHIC solutions obtained were compared with Teraoka-Hayakawa's theory for rodlike polymersolutions and with our fuzzy cylinder model theory for semiflexible polymer solutions. The formertheory agreed with the experimental results only for the second lowest molecular weight samplewith a rodlike conformation. On the other hand. the latter theory succeeded in explainingquantitatively the results for seven samples with intermediate molecular weights. Neither of thetheories agree with the data for the lowest molecular weight sample, because they neglected the

intermolecular hydrodynamic interaction which becomes important for short chain polymers. Forthe two highest molecular weight samples. the fuzzy cylinder model theory failed to describe the TJodata, because of some additional flexibility effect which is not cleared yet.

Pages 111-116


07:24:22


Dynamics of a semiflexible polymer poly(n-hexylisocyanate) in isotropic solution. 2. Dielectric dispersion

Masafumi Asano, Hiroyuki Kusuoka, Atsuyuki Ohshima, Takahiro

Sato, and Akio Teramoto

Department ofMacromolecular Science, Osaka University, Toyonaka,Osaka 560, Japan

Synopsis

Dielectric dispersions were measured for a semiflexible polymer, poly (n-hexyl isocyanate) (PHIC),in dilute through concentrated, isotropic solutions. Since PHIC has a dipole moment parallel to thechain contour, its dielectric dispersion reflects the fluctuation of the end-to-end vector of thepolymer. For lower molecular weight PHIC samples with rodlike nature (the Kuhn statisticalsegment number N ,,;; 0.53), the dispersion for the permittivity e' and the loss factor e" almostobeyed the simple Debye relation irrespective of the polymer concentration c , and the c dependenceof the dielectric relaxation time TV was favorably compared with the fuzzy cylinder model theory.

On the other hand, for higher molecular weight PHIC samples (N ;;. 0.69), the dispersion curves fore' and e" deviated from the Debye relation and the c dependence of TV did not agree with theprediction of the fuzzy cylinder model theory. These disagreements may ascribe to the chainflexibility effect for the higher molecular weight samples.

Pages 117-122


07:24:22

JAPAN ESE ABSTRACTS 801

Viscoelastic behavior of the crystallization of poly(phenylene sulfide sulfone) from N -methylpyrrolidone

solutions.

Yoshitaka Ishirnuro and Kazuhiko Ishikiriyarna

Material Characterization Laboratory, Sonoyama, Otsu, Shiga, 520Japan

Ukishige Kitano

X-Ray Crystallography Laboratory, Toray Research Center, Inc.,Sonoyama, Otsu, Shiga, 520 Japan

Yoshishige Fujii

Polymer Research Laboratories, Toray Industries, Inc., Sonoyama, Otsu,Shiga, 520 Japan

Synopsis

The isothermal crystallization of poly (phenylene sulfidesulfone) (PPSS) from N-methylpyrrolidone(NMP) solutions has been monitored by a viscoelastic technique. We have observed fourcharacteristic changes which occur with increasing time in 20 wt % solution at 24°C; (i) a decreasein 1]*, (ii] a steep increase in G', (iii) a slight decrease in 71*, and (iv) an increase in .,,* and G I.

These changes indicate the crystallization process from a nucleation to an aggregation. Further, thecrystallization at several temperatures and of poly (ethylene terephthalate) (PET), poly (butyleneterephthalate) (PBT) melts was measured similarly. It was found that the rate of crystallization ofPPSS from NMP solutions is very slow, and its temperature dependence is very small.

Pages 123-128


07:24:22


Viscoelasticity and birefringence ofpoly(2-vinylnaphthalene)

E. J. Hwang, Tadashi Inoue, and Kunihiro Osaki


Atsushi Takano

Nagaoka Technological University, Kamitomioka, Nagaoka, Niigata 94021, Japan

Synopsis

Complex Young's modulus, E*(w), and complex strain-optical coefficient, O*(w), of Poly(2-vinylnaphthalene) (P2VN) were studied in the glass-to-rubber transition zone at frequenciesranging from I to 130 Hz at various temperatures between 145 and 200 DC. In comparing the mastercurves of E*(w) and O*(w), we apply the modified stress-optical rule to deliberate the glasstransition modulus attributable to different relaxation mechanisms. The characteristics of mastercurves are also compared with those of polystyrene (PS), poly (a-methylstyrene) (PMS), andpolycarbonatc (PC) in view of their chemical structures. The stress-optical coefficient, C R '

determined in the rubbery zone, is - 8.3 X 10-9 Pa 1, which is 1.6 times larger than that of PS. Thelarge negative value may be due to the large optical anisotropy of naphthyl side group. In the glassyzone, the relative rate of decrease of E"(w) with w is lower compared with the other polymers. Thisbehavior is believed to be attributed to f3 relaxation of large naphthyl side group. Compared with thestrain-optical coefficients of three other polymers, the O*(w) of P2VN is found to be inactive to thef3 relaxation.

Pages 129-134

Viscoelastic entrance :flow of pipe with K-BKZ typemodel· Numerical Analysis·

Hiroshi Yamaguchi

Department of Mechanical Engineering, Doshisha University, KarasumaImadegawa, Kyoto 602, Japan

Synopsis

Viscoelastic flow at a region of a circular pipe entrance was examined numerically. The numericalcalculation was achieved by using I.c.E. (implicit continuous-fluid Eulerian) technique with theK-BKZ type constitutive equation. The transient flow characteristics with the sudden stand-up wereobtained. The resultant flow field and its associated flow parameters of the K-EKZ integralconstitutive equation were compared with the Newtonian case and the Oldroyd-B model. It isrevealed that flow is largely affected by a choice of the Deborah number. When the Deborah numberis high enough for a fixed Reynolds number, there would be a circulation zone at the entrance regionof the pipe by the effects of the viscoelasticity, which cannot be observed with the Newtonian flow.


07:24:22


Dynamic viscoelastic properties of incompatible polymerblends

Shuichi Maeda and Eiichi Kamei

Hirakata Laboratory, Ube Industries, Ltd., 3-10, Nakamiyakita-machi,Hirakata 573 Japan

Synopsis

Dynamic viscoelastic properties of phase-separated polypropylene (PP)/styrene-acrylonitrilecopolymer (SAN), PP/ethylene-propylene-rubber (EPR), and nylon6 (PA)/SAN blends preparedby melt blending were measured in molten state. As characteristic to heterogeneous liquids, slowrelaxation mechanisms due to domain structures of sizes := 0.1-20 ,urn were found for dynamicmoduli of three blends. These moduli were compared with predictions of an emulsion model ofPalierne developed for concentrated emulsions. The emulsion model with parameters determinedfor the components extracted from the blends quantitatively described the properties of the blends.This result suggested that the slow relaxation mechanisms of incompatible polymer blends wereattributed to recovery of domain shape and different in natUre from those of polymeric systemsbeing filled with inorganic solids and/or cross-linked rubber particles.

Pages 145-154

Influence of heterogeneous textures of polypropylene/ethylene-propylene-rubber blends on dynamic

viscoelastic properties in molten state

Takao Nomura and Takeyoski Nishio

Material Research and Development Div. II. Toyota Motor Corporation, 1,Toyota-cho, Toyota 471, Japan


Hirakata Laboratory, Ube Industries, Ltd., 3-10, Nakamiyakita-machi,Hirakata 573, Japan

Synopsis

Heterogeneous textures due to phase separation in molten polypropylene (PP)/ethylene-propylenerubber (EPR) blends were investigated in relation to their dynamic viscoelastic properties, Ascharacteristic to heterogeneous liquids, slow relaxation mechanisms due to the existence of suchphases were found for dynamic moduli of PPIEPR blends. These moduli were analyzed by using thelinear viscoelastic constitutive equation for an emulsion model developed for the concentratedemulsion and the blending equation for dissimilar polymer system. The results show that the matrixof PPIEPR blends is not pure PP but the mixture of PP and EPR. For the same blend composition,the EPR concentration in the matrix PP phase was larger for EPR containing more propylene units.For the blends having the same EPR, the EPR concentration in the matrix was larger for higher EPRcontent.


07:24:22


Influence of heterogeneous textures of polypropylene/ethylene-propylene-rubber blends on dynamic

viscoelastic properties in the solid

Talmo Nomura and Takeyoshi Nishio

Material Research and Development Div. II, Toyota Motor Corporation, 1,Toyota-cho, Toyota 471, Japan


Hirakata Laboratory, Ube Industries, Ltd., 3-10, Nakamiyakita-machi,Hirakata 573, Japan

Synopsis

Heterogeneous textures in phase separated, solid polypropylene (PP)/ethylene-propylene-rubber(EPR) blends were. investigated in relation to their dynamic viscoelastic properties. The glasstransition temperature ( Til) of amorphous PP phase in PPIEPR blend quenched from molten statevaries with propylene content of EPR as well as EPR content in blend. The Til depends on theconcentration of EPR dissolved in the amorphous PP phase. On the other hand, the Tg of EPR phasein PPIEPR blend is about the same as that of pure EPR. This fact means that PP molecules were notdissolved in EPR phase. For the same blending composition, the EPR concentration in matrix PPphase was larger for EPR having more propylene units. When the same EPR was used, the EPRconcentration in the matrix was larger for blends with larger EPR content. The EPR concentrationin the amorphous PP phase of PPIEPR blend in solid state is about the same as that in molten state,indicating that the EPR concentration in solid state was essentially determined by the EPRconcentration in" molten state.

Pages 165-172


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JAPANESE ABSTRACTS

Research on the mechanics of rubbers and fibrousmaterials

Sueo Kawabata, Professor emeritus

J(yoto [lniversity

Synopsis

805

For the past 30 years, the author has been conducting research on the mechanics of rubber elasticityand fibrous materials. This article presents a historical review of the development of the research.The author's first research project was an investigation of thickness irregularity in fiber bundles.This irregularity is caused by the random arrangement of the short fibers that form the bundle, andincreases during the drafting of the bundle in the spinning process. The author presented a theorythat made it possible to predict the power spectrum of this irregularity. This research stimulated theauthor's interest in the mechanics of fiber assembly bodies, also known as "fibrous materials." Thisinterest remains strong today. After completing his first research project, the author spent a year atthe California Institute of Technology, in Pasadena, where he initiated research on rubber elasticityas a basis for research on the failure behavior of solid rocket propellant. He has developed a biaxialextension experiment for rubbers. and found a simple form of the strain energy density function forthese rubbers. Parallel with this research on rubber elasticity, the author continued research on thedeformation mechanism of fibrous materials such as yarns and woven and knitted fabric structures.On the basis of this research, the author developed an objective evaluation of fabric hand:evaluations had previously been made by a subjective method called "hand judgment." There is asimilarity between research on the mechanics of rubber and research on the mechanics of fibrousmaterials. The research deals with the assembly body of molecular chain or fiber and have beencarried out with an interactive concept. The author has also introduced his recent research on themeasurement of anisotropy in the mechanical property of single fibers. This measurement wasconducted with a micromeasurement instrument developed by the author. Some of the results ofthese measurements are also presented here.

Pages 185-192


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Rheology of block copolymers and related entangledsystems

Hiroshi Watanabe


Synopsis

The relationship between rheological behavior and structures of styrene-butadiene (PS-PB)diblock copolymers was examined in a PB-selective solvent, n-tetradecane (CI4). At lowtemperatures the behavior of concentrated PS-PBfCI4 micellar solutions was dominated byplasticity due to a macro lattice of micelles. Thermodynamic confinement (balance of elastic andosmotic requirements) on corona PB blocks led to macrolattice formation. Differing from the

PS-PBfC 14 solutions, blends of PS-PB and homo-PB chains did not suffer from the confinementand exhibited linear viscoelastic relaxation that was retarded by entanglements of PB blocks. Infurther investigation of entanglement dynamics, constraint release (CR) relaxation in PSIPS binaryblends was found to be reasonably but not completely described by a Rouse-type CR model. Thismodel was further examined for dielectric relaxation of polyisoprene (PI) chains having dipolesparallel to the chain contour. Specifically, eigenfunctions associated with a local correlation functionwere evaluated from dielectric data of dipole-inverted PI chains. Those eigenfunctions werenonsinusoidal, most clearly exhibiting non-Rouse nature of actual CR processes.

Pages 193-204


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JAPANESE ABSTRACTS

Studies on nonlinear viscoelastic properties of wellentangled polymers and change in entanglement

structure

Yoshinobu Isono

807

Department of Chemistry, Faculty of Engineering, Nagaoka University ofTechnology, Nagaoka 940-21, Japan

Synopsis

Studies on nonlinear viscoelastic properties of well-entangled polymers and change in entanglementstructure by the author and his co-workers are summarized. In concentrated solutions and melts ofpolymers with high molecular weights, the polymers are entangled with each other, forming aquasinetwork structure. Each molecule is repeating the process of leaving old constraint andentering a new one, In the range of linear viscoelasticity, the dissolution and reformation ofentanglements are balanced. Hence the density of entanglement remains constant. Outside the rangeof linear viscoelasticity, however, the entanglement structure may be changed by external stimulisuch as shear strain and shear rate. Such an idea was supported by the observations of transientviscoelastic phenomena in various types of shear rate jump experiments. The relationship betweennonlinear viscoelasticity and change in entanglement structure was manifested from simultaneousmeasurements of stress growth and/or stress relaxation, and differential dynamic modulus by smalloscillatory deformations superposed on a large deformation. The entanglement structure does notchange from the equilibrium structure in the linear region, whereas it deviates from the equilibriumone in the nonlinear region. Such a change in entanglement structure arises from a decrease inentanglement density and an anisotropic configuration of the chain molecule.

Pages 205-214

Pressure characteristics of viscoelastic fluids in aconverging-diverging channel

Hiroshi Yamaguchi and Etsuro Noda

Department of Mechanical Engineering, Doshisha University, Kyoto 61003, Japan

Synopsis

Measurements of pressure at representative points in a converging-diverging channel were carriedout for viscoelastic liquids of aqueous solutions of poly-ethyleneoxide (PEa) and polyacrylamide(PAA) as well as for Newtonian liquids. The pressure drop at the section of converging channel andthe pressure rise at the section of diverging channel were simultaneously measured for various flowrates. The experimental results indicate that (i) magnitudes of both pressure drop and rise for thePEO solution increase with increasing PEO concentration, and the pressure characteristics aresimilar to those of Newtonian liquids, (ii) the pressure characteristics of the PAA solution aresignificantly different from those of Newtonian liquids when the PAA concentration is increased.The differences seem to be due to elasticity of the PAA solution.


07:24:22

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Motion of a rigid cylindrical particle in narrow channel flow

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