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Rheological properties of thermotropic liquid crystalline aromatic copolyesters
Author(s) -
Zhou Zhenglong,
Wu Xiuge,
Wang Meirong
Publication year - 1988
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.760280303
Subject(s) - thermotropic crystal , materials science , differential scanning calorimetry , polyester , scanning electron microscope , rheology , condensation polymer , polymer chemistry , shear thinning , atmospheric temperature range , liquid crystal , composite material , chemical engineering , liquid crystalline , polymer , thermodynamics , physics , optoelectronics , engineering
A series of thermotropic liquid crystalline polyesters based on p‐acetoxybenzoic acid, naphthalene dicarboxylic acid, hydroquinone diacetate, and poly(ethylene terephthalate) were prepared via melt polycondensation. The anisotropic melts were studied by means of thermal optical testing, differential scanning calorimetry, scanning electron microscopy. X‐ray diffraction, and rheological methods. It was found that the copolyesters in the mesomorphic state exhibit drastic shear‐thinning and the experimental results indicate that the non‐Newtonian Index n is in the range of 0.17 to 0.50, the flow‐activation energies Δ E η are 297.1 to 182.0 KJ/mol over the shear rate of 10 to 1000 S −1 at temperature 225 to 270°C; and the mesomorphic copolymers are readily oriented during processing, resulting in highly oriented as‐spun fibers.