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Thermal and shear flow effects on microstructure of a thermotropic liquid crystalline polymer
Author(s) -
Guo Tianren,
Naskar Amit K.,
Harrison Graham M.,
Ogale Amod A.
Publication year - 2006
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.20590
Subject(s) - materials science , thermotropic crystal , shear (geology) , rheology , composite material , shear flow , shear rate , shear stress , annealing (glass) , microstructure , polymer , simple shear , liquid crystalline , mechanics , physics
The effects of annealing time and temperature on the texture and transient shear rheological behavior of a thermotropic liquid crystalline polymer were investigated. The texture evolution during annealing included two processes: the reduction of the defect density and the increase of the domain size but decrease of the domain number. We confirmed that the threaded texture caused the first shear stress peak and the shear stress minimum during shear flow startup. More importantly, using the wide‐angle X‐ray diffraction technique, we determined that the second shear stress peak during flow startup can be attributed to the evolution of the molecular orientation. POLYM. ENG. SCI., 46:1215–1222, 2006. © 2006 Society of Plastics Engineers