ORDERING EFFECTS IN SHEAR FLOWS OF DISCOTIC POLYMERS

被引:23
作者
FARHOUDI, Y [1 ]
REY, AD [1 ]
机构
[1] MCGILL UNIV,DEPT CHEM ENGN,MONTREAL H3A 2A7,QUEBEC,CANADA
关键词
DISCOTIC NEMATIC POLYMERS; SHEAR FLOWS; ORDERING EFFECTS; ORIENTING REGIMES;
D O I
10.1007/BF00434185
中图分类号
O3 [力学];
学科分类号
08 ; 0801 ;
摘要
The tensorial mechanical model of Farhoudi and Rey (1993) for uniaxial, rodlike, spatially homogeneous and monodomain nematics is modified to describe the microstructural response of discotic nematic network polymers in rectilinear simple shear flow. The particular topological features of the discotic phase are taken into account by a proper modification of the phenomenological parameters. Asymptotic and numerical solutions of the microstructural balance equations indicate the appearance of tumbling, oscillating, and stationary flow regimes as the strength of shear increases, as is the case for rod-like nematic polymers (Marrucci, 1991). The tumbling-oscillating transition is characterized by a diverging tumbling function lambda, while the oscillating-stationary transition is characterized by a single steady value lambda smaller than -1. The stable steady states of the stationary regime are shown to belong to the family of unstable isotropic solutions that exist at small shear rates, and are characterized by a director angle close to, but less than +90-degrees to the flow direction.
引用
收藏
页码:207 / 217
页数:11
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