Novel poly(arylene ether ketone ketone)s synthesized by Friedel-Crafts acylation

Abstract

A series of novel poly(arylene ether ketone ketone)s were prepared from two novel oligomers and three different diacid chlorides via Friedel-Crafts polymerization. The oligomers 2,6-bis(4-phenoxybenzoyl)naphthalene and 5-tert-butyl-1,3-bis(4-phenoxybenzoyl)benzene were synthesized by Friedel-Crafts acylation of diphenyl ether with 2,6-naphthalenedicarbonyl dichloride and 5-tert-butylisophthaloyl dichloride, respectively, in the presence of AlCl3 as catalyst. Friedel-Crafts polymerization of either of these two novel oligomers with tert-butylisophthaloyl dichloride, isophthaloyl dichloride or 1,6-hexanedioyl dichloride gave six novel PEKK's, having Tg's in the range of 135--180°C, but only the naphthalene-based PEKKs displayed Tm's between 130 and 345°C. PEKK's containing the 5-tert-butylisophthaloyl group are soluble in polar solvents such as N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N,N-dimethylformamide, THF, chloroform etc. Polymer PA1, which has a fully unsubstituted aromatic chain structure, is insoluble in common organic solvents and, moreover, shows polymorphism. Intrinsic viscosities and adhesion behavior of soluble PEKKs were also determined.