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Rheology and structure of liquid crystalline alkylenearomatic polyesters
Author(s) -
Kulichikhin G. V.,
Dreval' V. E.,
Kotova E. V.,
Antipov E. M.,
Godovsky Yu. K.,
Zuev V. V.
Publication year - 1993
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.760331404
Subject(s) - materials science , copolyester , polyester , rheology , crystallite , phenylene , liquid crystal , metastability , polymer , phase (matter) , composite material , polymer chemistry , chemical engineering , crystallography , organic chemistry , chemistry , optoelectronics , engineering , metallurgy
The rheological, thermodynamic and structural properties of two liquid crystalline polyesters—poly(oxyfumaroyloxy‐ 1,4‐phenylene carbonyloxyalkyleneoxycarbonyl‐ 1,4‐phenylene)s with six and ten methylene groups (PES‐6 and PES‐ 10, respectively) and a statistical copolyester (co‐PES) have been investigated. It has been shown that they all form a smectic LC‐phase. The change from homopolyesters to co‐PE S expands the temperature range of the LC‐state. The high sensitivity of the structure to the prehistory in the melt state is typical for such copolymers. Prolonged heating leads to rearrangement of the co‐PES crystalline structure and a drastic increase in viscosity. The orientation of these polymers during flow was investigated. It was shown that a high level of molecular orientation of the smectic layers, perpendicular to the direction of flow, was realized at high shear stresses. In the melt region, the existence of a metastable network with junctions of crystalline nature hinders the flow of the homo‐ and copolyesters. The structure of the unit cell of the crystallites depends on the composition and thermal history.