LC-polyimide 38. Smectic poly(ester-imide)s of N,N-bis (4-hydroxy-phenyl)biphenyl-3,3 ',4,4 '-tetracarboxylic imide having long aliphatic spacers. Part I

A new monomer (7) was prepared by alkylation of N,N,-bis(4-hydroxyphenyl)bi phenyl-3,3',4,4'-tetracarboxylic imide with 11-bromoundecanol. This imide d iol (7) did not form a LC-phase, but showed two reversible first-order tran sitions in the solid state. It was polycondensed with various aliphatic dic arboxylic acid dichlorides in 1-chloronaphthalene. The phases and phase tra nsitions of the resulting poly(ester-imide)s were characterized by optical microscopy, DSC measurements and X-ray measurements at variable temperature . All poly(ester-imide)s formed a crystalline smectic phase in the solid st ate. In the case of short spacers enantiotropic smectic-A phase were observ ed which vanished in the case of long spacers. (C) 2000 Elsevier Science Lt d. All rights reserved.