MORPHOLOGICAL-STUDIES OF BISPHENOL SERIES THERMOTROPIC LIQUID-CRYSTALLINE WHOLLY AROMATIC COPOLYESTERS

A family of aromatic thermotropic liquid crystal (TLC) copolyesters ar e prepared based on terephthalic acid (TPA), isophthalic acid (IPA), p -hydroxybenzoic acid (HBA), and a family of bisphenols. The morphologi cal behaviors of the copolyesters are studied by using polarized optic al microscopy, small-angle light scattering (SALS), and depolarized li ght intensity (DLI) analysis. The copolyester melts exhibit nematic me sophase textures within wide temperature ranges without showing transi tions to isotropic phases. The textures under different temperatures a nd deformation conditions are investigated. Scattering patterns of the mesophases change greatly during shear deformation and relaxation. Th e early formation of the mesophases is a one-dimension heterogeneous n ucleation based on isothermal condition. (C) 1994 John Wiley & Sons, I nc.