SYNTHESIS AND CHARACTERIZATION OF LIQUID-CRYSTALLINE COPOLYESTER OF 4-HYDROXY-2,3,5,6-TETRAFLUOROBENZOIC ACID WITH 6-HYDROXY-2-NAPHTHOIC ACID

4-Hydroxy-2,3,5,6-tetrafluorobenzoic acid/6-hydroxy-2-naphthoic acid c opolymers (FHBA/HNA copolymer) with different copolymer compositions w ere prepared and the influence of FHBA residue on the thermal properti es and structures of the copolymers were investigated. Introduction of FHBA decreased the crystal/nematic phase transition temperatures (T(C N)s) of the FHBA/HNA copolymers. T(CN)s Of the copolymers were in the temperature range between 200 and 250 degrees C, depending on the copo lymer composition. They are approximately 40 degrees C lower than thos e of 4-hydroxybenzoic acid/HNA copolymers. FHBA/HNA copolymers exhibit ed low crystallinity, and annealing treatment hardly influenced the cr ystalline natures. FHBA residue possibly interferes with the recrystal lization during annealing. (C) 1998 John Wiley & Sons, Inc.