Rheology of liquid crystalline solutions of hydroxypropyl cellulose in m-cresol

Suto, Shinichi; Gotoh, Hiromasa; Nishibori, Wataru; Karasawa, Mikio

doi:10.1002/app.1989.070370425

Cited by 12 publications

(16 citation statements)

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“…[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: Introductionsupporting

confidence: 41%

“…Although the conditions (shear rate) were slightly different from those in this work, the critical concentrations for both systems were almost the same as those already determined for the same systems by our group. 18,19 The data in Figure 4 indicated that the HPC/DMAc system was isotropic below 48 wt %, biphasic between 48 and 53 wt %, and fully anisotropic above 53 wt %. The HPC/m-cresol system was isotropic below 25 wt %, biphasic between 25 and 30 wt %, and fully anisotropic above 30 wt %.…”

Section: Phase Transformation Of Our Systemsmentioning

confidence: 95%

“…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: 95%

“…We, however, have already obtained the phase diagrams for the same systems (using the same samples) and could easily estimate the critical concentration at 30°C: the critical concentration was 54 wt % for the HPC/DMAc system and 28 wt % for the HPC/m-cresol system. 18,19 Another important feature in Figure 8 was that S R for the fully anisotropic phase was greater than that for the isotropic phase. The values of S R were over 2 for the fully liquid crystalline phase.…”

Section: Dependence Of S R On Concentrationmentioning

confidence: 97%

“…18,19 We need to show the critical concentration for each system, because the rheological behavior greatly depends on the phase (isotropic, biphasic, and fully anisotropic). The critical concentration can be evaluated from the viscosityconcentration curve and from the polarized microscopy.…”

Section: Phase Transformation Of Our Systemsmentioning

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: Introductionsupporting

confidence: 41%

Section: Phase Transformation Of Our Systemsmentioning

confidence: 95%

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

confidence: 95%

Section: Dependence Of S R On Concentrationmentioning

confidence: 97%

Section: Phase Transformation Of Our Systemsmentioning

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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Swelling behavior of crosslinked hydroxypropylcellulose films retaining cholesteric liquid crystalline order, II. Effects of temperature, solvent, and pH

Suto¹,

Umeda

1999

Angew. Makromol. Chem.

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Crosslinked hydroxypropylcellulose (HPC) films were cast from the cholesteric liquid crystalline HPC solution in methanol. The films retained the cholesteric liquid crystalline order. The dependences of swelling behavior of our films in water and propanol on temperature and on pH of the solvent were determined. The response of our films to the changes in water, temperature and in pH was discussed. In water, the equilibrium swelling ratio (Be) decreased with temperature whereas Be increased with temperature in propanol. For a given composition of water and propanol, Be was independent of temperature. Be in the acidic solvents was higher than in the alkaline solvents. The response data to the stepwise change in temperature revealed that the deswelling behavior was more rapid than the swelling behavior in water, and the swelling‐deswelling behavior was reversible. The response to the stepwise change in pH was almost the same as that of the change in temperature, but the surface of the film was attacked by the acid and became fluffy with increasing soaking time.

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Viscometric behavior of ternary concentrated solutions of hydroxypropyl cellulose and ethyl cellulose in m‐cresol

Suto

Kosaka

Sugiura

1992

J of Applied Polymer Sci

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SYNOPSISThe shear viscosity of blend solutions of hydroxypropyl cellulose (HPC ) and ethyl cellulose (EC) in m-cresol (both HPC/m-cresoi and EC/rn-cresol systems form lyotropic liquid crystals) was determined by cone-plate-type and capillary-type viscometers. The textures for the same systems at rest and undergoing shear were also observed with a polarized microscope.At shear rate of 1 s -l , viscosity exhibited a maximum and a minimum with respect to temperature, and this suggested that the phase of the matrix dominated the viscometric behavior of the ternary systems; the blend composition dependence of the viscosity was not additive, and this suggested that HPC and EC were immiscible. At relatively high shear stress, the blend composition dependence of the viscosity greatly depended on the total polymer concentration of the solutions and was quite different from that at low shear rate; the texture of the anisotropic solutions was also different from that at low shear rate. Our findings suggested that the dependence of viscosity on shear and concentration for pure HPC solution was different from that for pure EC solution.

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Rheology of liquid crystalline solutions of hydroxypropyl cellulose in m-cresol

Cited by 12 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

Swelling behavior of crosslinked hydroxypropylcellulose films retaining cholesteric liquid crystalline order, II. Effects of temperature, solvent, and pH

Viscometric behavior of ternary concentrated solutions of hydroxypropyl cellulose and ethyl cellulose in m‐cresol

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