PROPERTIES AND MICROSTRUCTURE OF AROMATIC LIQUID CRYSTALLINE COPOLYESTERS

摘要

The properties and structures of thermotropical liquid crystalline copolyesters basedon p-hydroxybenzoic acid (PHBA), terephthalic acid (TPA) and bisphenol A (BPA) werestudied by DSC, WAXD, hot stage polarized microscopy and NMR. It was found that mostof the copolyesters were soluble in many common organic solvents. The copolyesters hadfow T_m/T_f values and a broad range of liquid crystal phase, making the polymers readilymelt-processable. The effects of annealing at different temperatures on the copolyestercontaining 33% PHBA were also discussed. It was noted that annealing at ca. 200℃(below Tc - n) could lead to the increasing of the crystallinity of the copolyester while themicrostructure and sequence structure had not changed. Annealing at ca.280℃ (nearTc - n) could bring a change of crystal and sequence structure and simultaneously madethe ndcrodomains be ordered more perfectly.