SYNTHESIS AND PROPERTIES OF COPOLYESTERS HAVING AN ORDERED COMONOMER SEQUENCE - COPOLYESTERS PREPARED FROM NAPHTHYLENE BIS(4-HYDROXYBENZOATE)S AND ALPHA,OMEGA-BIS(4-CARBOXYPHENOXY)ALKANES

A series of sequentially ordered copolyesters were prepared from isome ric naphthylene bis(4-hydroxybenzoate)s (NBHBs) and alpha,omega-bis(4- carboxyphenoxy)alkanes (BCPAs) with varying length of alpha,omega-alky lene units. All of the copolyesters were composed of naphthalenediol ( NAPH), BCPA and p-hydroxybenzoic acid (POB) (1:1:2 molar ratio). The p olymer chains were made up of -POB-NAPH-POB-BCPA-segments. The naphtha lene units were derived from 1,5-, 1,6-, 2,6- and 2,7-naphthalenediols . The BCPAs employed were 1,4-butane, 1,5-pentane and 1,10-decane deri vatives. The melting points and crystallizability of these copolyester s were found to be much higher than those of the corresponding random copolyesters having the same overall compositions. All of the polymers , with the exception of the polyester derived from 2,7-naphthalenediol and 1,5-pentane spacers, formed nematic phases in melts. The ordered sequence copolyesters were found to undergo a rapid sequence randomiza tion at temperatures higher than their melting points. A model compoun d of a copolyester, 2,7-naphthylene bis[4-(4-n-butoxybenzoyloxy)-benzo ate], was also synthesized and its thermal behaviour and liquid crysta l properties were studied.