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Effect of shear on subsequent rheological transients in polymeric liquid crystals
Author(s) -
Moldenaers P.,
Mewis J.
Publication year - 1989
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19890230112
Subject(s) - rheology , shearing (physics) , materials science , liquid crystal , shear rate , shear stress , shear flow , mechanics , lyotropic liquid crystal , moduli , lyotropic , shear (geology) , composite material , thermodynamics , liquid crystalline , physics , optoelectronics , quantum mechanics
The transient rheological behaviour of a lyotropic polymeric liquid crystal is investigated. The system consists of a 12% by weight solution of poly(γ‐benzyl‐L‐glutamate) in m‐cresol. The structural changes caused by steady state shearing and by large amplitude oscillatory flow are measured. This is done by following the linear moduli upon cessation of flow. The stress transients during a stepwise increase in shear rate are used for the same purpose. Flow always increases the subsequent moduli in the system used, but the mode and the intensity of the flow have a complex effect. The variable domain structure seems to be responsible for most of the measured behaviour. The data put specific constraints on the detailed mechanisms that can contribute to the global transient stress.