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Thermotropic liquid‐crystalline polymers having five‐membered heterocycles as mesogens, 3. New semi‐rigid thermotropic liquid‐crystalline polyesters based on a twin biphenyl analogue of 1,3,4‐thiadiazole
Author(s) -
Sato Moriyuki
Publication year - 1999
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/(sici)1521-3927(19990201)20:2<77::aid-marc77>3.0.co;2-j
Subject(s) - thermotropic crystal , liquid crystal , biphenyl , polyester , liquid crystalline , materials science , condensation polymer , polymer , polymer chemistry , phase (matter) , melting point , crystallography , organic chemistry , chemistry , composite material , optoelectronics
New semi‐rigid thermotropic liquid crystalline (LC) polyesters containing a twin biphenyl analogue of 1,3,4‐thiadiazole in the main chain were prepared by melt polycondensation of the bismethyl ester derivative of twin 2‐phenyl‐1,3,4‐thiadiazole having a decamethylene segment in the central part with three aliphatic diols. The polymer with an octamethylene segment forms a monotropic nematic phase and those with decamethylene and dodecamethylene segments form enantiotropic smectic phases, although their LC states are unstable. The melting and isotropization temperatures decrease with increasing length of alkylene spacers.