Abstract
Novel liquid crystalline copoly (ester imide)s were synthesized via polyesterification of triethyleneglycol bis(4-carboxyphenyl) ether (1e), diacetoxybiphenyl, and diacids with imide moieties. The effects of composition on the changes of T g , T m , and T i were examined by global TSC 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, displayed particular liquid crystalline behavior. Copolymers with higher aromatic imide ring content (4a-d, 5a-g) form a layered structure and an enantiotropic smectic mesophase in the melting state. The melt viscosity of the semetic mesophase was higher than the nematic mesophase which was observed by capillary rheometer. © 1998 John Wiley & Sons, Inc.