ISSN:
0887-624X
Keywords:
block copolymers
;
triad mesogen
;
ethylene terephthalate segments
;
nematic
;
biphasic
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Liquid crystalline block copolymers containing different compositions of terephthaloyl bis(4-oxybenzoyl) (triad) mesogen and flexible ethylene terephthalate (ET) units, were synthesized in tetrachloroethane/pyridine (TCE/Py) at 150°C and in 1-chloronaphthalene (1-CN) at elevated temperatures. Inherent viscosities of the PET block copolymers were always lower than 0.25 dL/g. By replacing the ET blocks with butylene terephthalate (BT) blocks, a copolymer of higher inherent viscosity (〉 0.8 dL/g) was synthesized in 1-CN at 220°C. Formation of low molecular weight PET copolymers was attributed to: (1) insolubility of the block copolymer in TCE/Py and (2) formation of side products which alter the stoichiometry of the reactants when the reaction was carried out in 1-CN. The block copolymers were characterized by 1H and 13C-NMR spectroscopy. Copolymer compositions were calculated from 1H and 13C-NMR data. Thermal behavior of these copolymers was analyzed by DSC and polarizing optical microscopy. All copolymers exhibited a nematic liquid crystalline texture. © 1995 John Wiley & Sons, Inc.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pola.1995.080330815
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