Rheology of region I flow in a lyotropic liquid‐crystal polymer: The effects of defect texture
作者:
Lynn Walker,
Norman Wagner,
期刊:
Journal of Rheology
(AIP Available online 1994)
卷期:
Volume 38,
issue 5
页码: 1525-1547
ISSN:0148-6055
年代: 1994
DOI:10.1122/1.550557
出版商: The Society of Rheology
关键词: DEFECT STRUCTURE;CELLULOSE;PROPYL COMPOUNDS;LIQUID CRYSTALS;POLYMERS;LYOTROPIC CRYSTALS;SHEAR PROPERTIES;TRANSIENTS;SOLUTIONS;VISCOSITY;LIGHT SCATTERING;MOLECULAR WEIGHT
数据来源: AIP
摘要:
A thorough rheological investigation into the region I flow of liquid‐crystalline hydroxypropylcellulose in water is reported. At low shear rates a region of shear thinning with a power‐law exponent 1/2 is observed over two decades in shear rate. Anomalous transient behavior is seen for applied stresses below the critical stress at the region I–II turnover such that the strain required to reach steady state increases as stress decreases. Recoil measurements show large recoverable strain and similar pseudostrain scaling in both regions I and II. The activation energy for the viscosity is also the same in regions I and II. This rheology combined withinsituflow‐small‐angle light scattering measurements of the defect texture size show the qualitative and quantitative accuracy of the defect texture stress balance previously proposed to explain region I flow.
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