SYNTHESIS AND PROPERTIES OF POLY(ALKYLENE P,P'-BIBENZOATE-CO-ADIPATE)S

Various poly( alkylene p,p'-bibenzoate-co-adipate)s were prepared by m elt polycondensation of dimethyl-p,p'-bibenzoate, adipic acid, and an alkylene glycol. The copolyesters were characterized by inherent visco sity, FTIR, proton NMR, DSC, polarized microscopy, and X-ray diffracti on. The polymer composition and sequence distribution of the copolyest ers can be seen from NMR spectra. The copolyesters exhibit a degree of randomness of about 1, indicating that they are random copolymers. Fr om the DSC data, the glass transition temperature (T-g) and melting po int (T-m) of the copolyesters can be detected. When the content of the flexible adipate unit increases, the T-g of copolyesters decreases si gnificantly. The type of alkylene glycol used also affects the T-g to some extent. The copolymerization effect decreases crystallinity and t he T-m of the copolyesters. The DSC, polarized microscopy, and X-ray d iffraction data show that some copolyesters derived from 1,6-hexanedio l exhibit a monotropic smectic phase. As the molar fraction of adipate unit in diacid units, x, is more than 0.4, the liquid crystallinity i s completely destroyed. (C) 1997 John Wiley & Sons, Inc.