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Polydomain model predictions of molecular orientation in isothermal channel flows of thermotropic liquid crystalline polymers
Author(s) -
Fang Jun,
Burghardt Wesley R.,
Bubeck Robert A.
Publication year - 2008
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.21176
Subject(s) - materials science , thermotropic crystal , extrusion , isothermal process , orientation (vector space) , shear (geology) , polymer , channel (broadcasting) , mechanics , statistical physics , thermodynamics , composite material , liquid crystalline , physics , geometry , computer science , computer network , mathematics
We report process simulations of molecular orientation of liquid crystalline polymers for isothermal channel flows in extrusion. The simulations use a “polydomain” model due to Larson and Doi (Larson and Doi, J. Rheol ., 35, 539 (1991)), which is implemented by exploiting a nearly exact analogy with a fiber orientation model that is widely used for analysis of composites processing. Simulation results are compared to experimental data previously obtained using a customized X‐ray capable extrusion die that allows a wide range of channel flow geometries to be explored. Competition between inhomogeneous shear and extension in these kinematically complex flows has a profound effect on the resulting molecular orientation distributions. We find that the Larson–Doi model successfully predicts most aspects of the experimental observations, demonstrating its utility for process modeling. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers