Rigid-rod benzobisazole copolymer containing cyclic phosphate ester

Abstract

Rigid-rod aromatic heterocyclic copolymers having repeating units of the formula: ##STR1## wherein n has a value of about 0.10 to 0.99, m is 1.0-n, Ar is a para-ordered divalent aromatic moiety, as defined hereinafter, and wherein Ba is a benzobisazole moiety of the formula: ##STR2## wherein X is --O--, --S-- or --NH. Ar can be any para-ordered divalent moiety such as, for example, 1,4-phenylene, 4,4'-biphenylene, 4,4"-terphenylene, and the like, as well as substituted divalent moieties, such as, for example: ##STR3## wherein R is Q or an alkyl group having 1 to 4 carbon atoms, wherein Q is ##STR4## wherein Z is --O-- or --S--; ##STR5## wherein R is as defined above, or ##STR6## wherein R.sup.1 and R.sup.3 are --H or -phenyl, R.sup.2 is --H or ##STR7## wherein Q is as defined above, and R.sup.4 is R.sup.2 or ##STR8##

Dependencies are inferred from the claim text.