Poly(aryl ether ketone) synthesis via competing S NAR and S RN1 reactions: 1. Polymers derived from 1,3-bis( p-chlorobenzoyl)benzene and 1,3-bis( p-fluorobenzoyl)benzene with hydroquinone and 4,4′-isopropylidenediphenol

Abstract

Poly(aryl ether ketone)s were synthesized by the reaction of 1,3-(bischlorobenzoyl)benzene or the corresponding fluoro analogue with bisphenoxides derived from either hydroquinone or 4,4′-isopropylidenebiphenol (bisphenol-A). With the stronger nucleophile, obtained from bisphenol-A, and either of the dihalides, high molecular weight polymers are formed exclusively via a nucleophilic aromatic substitution (S NAR) reaction. A similar reaction leads to the formation of a high molecular weight polymer when the weaker nucleophile, derived from hydroquinone, is allowed to react with the bisfluoride. On the other hand, oligomeric products are obtained when the bischloride is treated with this weaker nucleophile. In this case, both S NAR and S RN1 (substitution, radical-nucleophilic, unimolecular) mechanisms are operative for the replacement of the chlorine atoms. The S RN1 pathway, which is responsible for the formation of oligomeric products, can be eliminated by the addition of a suitable radical scavenger. High molecular weight poly(aryl ether ketone) is then formed via the S NAR mechanism.