Tf. Hsu et al., SYNTHESIS AND CHARACTERIZATION OF NOVEL THERMOTROPIC LIQUID-CRYSTALLINE COPOLY(ESTER IMIDE)S, Journal of polymer science. Part A, Polymer chemistry, 36(11), 1998, pp. 1791-1803
Novel liquid crystalline copoly(ester imide)s were synthesized via pol
yesterification of triethyleneglycol bis(4-carboxyphenyl) ether (le),
diacetoxybiphenyl, and diacids with imide moieties. The effects of com
position on the changes of T-g, T-m, and T-i were examined by global T
SC and DSC. Thermal gravimetric analyses (TGA) found that 4a-d and 5a-
g possess higher thermal stability. Strong stir opalescence phenomenon
and observations from polarized optical microscopy identified that 2b
-e and 3a-d possess the typical schlieren texture of an enantiotropic
nematic mesophase. The birefrigent melts of 4a-d and 5a-g, however, di
splayed particular liquid crystalline behavior. Copolymers with higher
aromatic imide ring content (4a-d, 5a-g) farm a layered structure and
an enantiotropic smectic mesophase in the melting state. The melt vis
cosity of the semetic mesophase was higher than the nematic mesophase
which was observed by capillary rheometer. (C) 1998 John Wiley & Sons,
Inc.