Capillary Flow Properties of Lyotropic Liquid Crystalline Solution of Hydroxypropyl Cellulose in Acetic Acid

Suto, Shinichi; Ohshiro, Masahiko; Ito, Ryoko; Karasawa, Mikio

doi:10.1678/rheology1973.14.2_87

Cited by 3 publications

(3 citation statements)

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“…[5][6][7] Only our data indicated relatively greater die swell behavior. [1][2][3][4] Our finding in Figure 8 was in harmony with our die swell behavior and was not with other groups' die swell behavior.…”

Section: Dependence Of S R On Concentrationsupporting

confidence: 62%

“…[1][2][3][4] Our numerical values of the die swell were relatively greater than others observed by some other researchers. [5][6][7] Now, it seems to be that generally the liquid crystals have less die swell than the isotropic solutions or melts, contrary to our data.…”

Section: Introductioncontrasting

confidence: 55%

“…This trend of S R behavior was similar to the first normal stress difference behavior 20,21 and the die swell behavior. [1][2][3][4] Consequently, the elastic properties for the liquid crystal-forming system depended on the phase of the system as the viscometric properties did.…”

Section: Dependence Of S R On Shear Stress Prior To Recoverymentioning

confidence: 99%

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Recoverable shear strain of liquid crystal‐forming concentrated hydroxypropyl cellulose solutions

Suto

Mitamura

Sasaki

2002

J of Applied Polymer Sci

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ABSTRACT:The recoverable shear strain (S R ) for the liquid crystal-forming hydroxypropyl cellulose solutions was determined by means of a concentric cylinder rotational apparatus as functions of shear stress prior to recovery and concentration of the solutions at 30°C. S R greatly depended on shear stress and concentration; the phase of the solution (the single phase or biphase) governed the dependences of S R on stress and concentration. S R increased with increasing stress for the single phase and decreased for the biphase. S R seemed to be related to the die swell (B): S R ϰ B n . S R exhibited a maximum and a minimum with respect to concentration. S R for the cellulosic cholesteric liquid crystalline solutions was greater than that for the isotropic solutions. A model was proposed for explaining the greater S R .

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Section: Dependence Of S R On Concentrationsupporting

confidence: 62%

Section: Introductioncontrasting

confidence: 55%

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Recoverable shear strain of liquid crystal‐forming concentrated hydroxypropyl cellulose solutions

Suto

Mitamura

Sasaki

2002

J of Applied Polymer Sci

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Die swell of liquid crystal‐forming solutions of hydroxypropyl cellulose through a long capillary die

Suto

Yoshida

1995

Angew. Makromol. Chem.

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The die swell and shear viscosity of lyotropic liquid crystal-forming hydroxypropyl cellulose solutions in N,N-dimethylacetamide were determined over a relatively wide range of shear stress or polymer concentration at 30°C by using a long capillary die with an aspect ratio of 114. The dependence of die swell on the concentration was similar to that of shear viscosity: a maximum at a critical concentration C, and a minimum at another critical concentration C, (C, < cb). The dependence of the swell on shear stress is greatly affected by the solution phase: in an isotropic range (below C.&, the die swell increased monotonously with shear; in the vicinity of C,, the die swell exhibited a maximum; in a biphasic range (between C, and C,), the die swell decreased monotonously; in a single-phase anisotropic range (above C,), the die swell exhibited a minimum. Above C,, extrudate distortion was observed and disappeared around the shear where the die swell exhibited a minimum. ZUSAMMENFASSUNG:Die Strangaufweitung und die Scherviskositat von lyotrop fliissigkristallinen Liisungen von Hydroxypropylcellulose in N,N-Dimethylacetamid wurden in einem relativ breiten Scherspannungs-und Konzentrationsbereich bei 30 "C mit einer langen Kapillardiise mit einem Achsenverhaltnis von 114 gemessen. Die Strangaufweitung hingt in ahnlicher Weise von der Konzentration ab wie die Scherviskositat; sie zeigt ein Maximum bei einer kritischen Konzentration C, und ein Minimum bei einer weiteren kritischen Konzentration Cb, wobei C, < C,. Die Abhangigkeit der Strangaufweitung von der Scherspannung wird stark von der Zahl der Phasen der Usung bestimmt: Im isotropen Bereich unterhalb C, nimmt die Strangaufweitung mit der Scherspannung monoton zu; nahe C, durchlauft sie ein Maximum; in einem zweiphasigen Bereich zwischen C, und c b nimmt sie wieder ab und durchlauft im einphasig-isotropen Bereich oberhalb c b ein Minimum, wobei eine oberhalb C, auftretende Distorsion des Extrudats im Bereich des Minimums verschwindet.

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Capillary flow properties of thermotropic hydroxypropylcelluloses

Fujiyama

1990

J of Applied Polymer Sci

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SynopsisThe influences of molecular weight, temperature, and shear rate on the capillary flow properties of thermotropic hydroxypropylcelluloses have been studied. The crystalline/liquid crystalline transition temperature and the temperatures at which the liquid crystalline/isotropic transition begins and ends are higher as the molecular weight is higher. The flow curves show yield stresses and, contrary to general thermoplastic resins, the slope of log(viscosity)-log(shear rate) curve decreases as the shear rate increases. This tendency is more notable as the molecular weight is higher. The temperature change of the viscosity shows a minimum and the minimum moves to a higher temperature with increasing shear rate. The moving rate is higher as the molecular weight is higher. This is because the molecular orientation of the isotropic phase increases with increasing shear rate. Contrary to general thermoplastic resins, the molecular weight dependence of the viscosity increases with increasing shear rate. The yield stress is higher as the molecular weight is higher and shows a minimum at 200-21OoC. The molecular weight dependence of the entrance pressure loss is higher than that of the viscosity. The end correction coefficients of the hydroxypropylcelluloses are very much higher than those of general thermoplastic resins: They exceed 50 in some cases. The temperature change of the end correction coefficient shows a maximum and the temperature at the maximum is higher as the molecular weight is higher. The die swell ratio shows a minimum at 180-220°C at low shear rates and the minimum swell ratio is lower than unity in some cases. The die swell ratio is higher as the molecular weight is increased.

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Capillary Flow Properties of Lyotropic Liquid Crystalline Solution of Hydroxypropyl Cellulose in Acetic Acid

Cited by 3 publications

References 0 publications

Recoverable shear strain of liquid crystal‐forming concentrated hydroxypropyl cellulose solutions

Recoverable shear strain of liquid crystal‐forming concentrated hydroxypropyl cellulose solutions

Die swell of liquid crystal‐forming solutions of hydroxypropyl cellulose through a long capillary die

Capillary flow properties of thermotropic hydroxypropylcelluloses

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