Synthesis and properties of soluble aromatic poly(ether benzoxazole)s from 9,9-bis[4-(4-amino-3-hydroxyphenoxy)phenyl]fluorene and aromatic dicarboxylic acid chlorides

Abstract

An ether-containing bis(o-aminophenol) monomer having a bulky diphenylfluorene unit, 9, 9bis[4-(4-amino-3-hydroxyphenoxy)phenyl]fluorene, was synthesized by the reaction of 9, 9-bis(4-hydroxyphenyl)fluorene with 2-benzyloxy-4-fluoronitrobenzene giving a bis-nitrobenzene compound, followed by catalytic reduction. Diphenylfluorene-containing aromatic poly(ether benzoxazole)s (PEBOs) having inherent viscosities of 0.57-0.74 dl g(-1) were obtained in two steps by the polycondensation of the bis(o-aminophenol) with various aromatic dicarboxylic acid chlorides giving precursor poly(ether o-hydroxyamide)s, and subsequent thermal cyclodehydration. These aromatic PEBOs were soluble on heating in N-methyl-2-pyrrolidone and m-cresol. The glass transition temperatures and 10% weight loss temperatures of the PEBOs were in the ranges of 258-294 degreesC and 560-580 degreesC, respectively, in nitrogen.