iquid Crystalline copolyesters containing poly(ethylene terephthalate)(PET) and high proportion of p-hydroxybenzoic acid(PHB) moieties up to 80 mol%

were prepared by conventional(one-step)and two-step polycondenstion processes and the products were studied by visual observation under polarizing microscope thermomechanical analysis and 1H-NMR spectroscopy . The copolyester prepared by one-step process has a blockmicrostructure

as verified by 1H-NMR study.Whereas a more random copolyester with an obviously decreased amount of insoluble fraction was obtained by two-step process.Their soluble fractions have a random sequence distribution and could be dissolved in P-chlorophenol and tetrachloroethane solvent mixture even if the PHB moiety content is as high as 80 mol%.