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Rheological properties of liquid crystalline copolyesters
Author(s) -
Prasadarao M.,
Pearce E. M.,
Han C. D.
Publication year - 1982
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1982.070270424
Subject(s) - terephthalic acid , rheometer , materials science , rheology , hydroquinone , polyester , polymer chemistry , shear rate , copolyester , shear stress , ethylene , composite material , chemical engineering , organic chemistry , chemistry , catalysis , engineering
Copolyesters were synthesized by modifying poly(ethylene terephthalate) (PET) with p ‐acetoxybenzoic acid (PAB) and hydroquinone diacetate/tetrasubstituted (tetramethyl, tetrachloro, and tetabromo) terephthalic acid (HQTS). It was found that the copolyesters containing 33 mol% or higher concentrations of (PAB+HQTS) from mesomorphic liquid crystalline structures. Rheological properties of copolyesters formed of PET, modified with PAB and hydroquinone diacetate/tetramethyl terephthalic acid (HQTM), were measured using a cone‐and‐plate rheometer. It was found that the copolyesters in the mesomorphic state exhibit yield values at a low shear rate (or at a low shear stress), and negative values of first normal stress difference were observed for certain compositions of (PAB+HQTM), over the range of shear rates (or shear stresses) tested.