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Deorientation effects on extrusion rheometry of a thermotropic copolyester
Author(s) -
Tormes Marta,
Muñoz María Eugenia,
Santamaría Anton
Publication year - 1997
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.1997.030180709
Subject(s) - rheometry , thermotropic crystal , copolyester , extrusion , materials science , rheometer , rheology , composite material , extrusion moulding , viscosity , capillary action , shear (geology) , shear flow , polymer , polymer chemistry , mechanics , liquid crystalline , physics , polyester
Extrusion rheometry experiments with a commercial thermotropic liquid crystalline copolyester show concave Bagley plots and convex pressure profiles. A loss of the orientation produced at the entrance of the capillary and the slit can explain these non‐linearities. Assuming that the order parameter, S , relaxes exponentially with time, the Doi‐Edwards model for the shear flow of rod‐like polymers is used to adjust experimental data.