POLY(ARYL ETHER KETONE) BLOCK AND CHAIN-EXTENDED COPOLYMERS .1. PREPARATION AND CHARACTERIZATION OF A NEW CLASS OF FUNCTIONAL POLY(ARYL ETHER KETONE) OLIGOMERS

A series of poly(aryl ether ketone) (PAEK) oligomers with controlled m olecular weights and end groups has been prepared via the Friedel-Craf ts reaction of terephthaloyl chloride with diphenyl ether in the prese nce of either p-fluorobenzoyl chloride or fluorobenzene as the chain-t erminating agents. The p-fluorobenzoyl chloride route is preferred, an d the reaction is carried out in 1,2-dichloroethane, at 20-30 wt % sol ids, in the presence of a 30-40 mol % excess of aluminum chloride. A t roublesome side reaction involving alkylation of the benzene rings is minimized under these conditions and is further minimized by the addit ion of a complexing agent. The oligomers were characterized by fluorin e content, C-13 NMR, laser desorption-mass spectrometry, and GPC, whic h proved to be a powerful tool for the determination of purity. The fl uorine contents agreed well with calculated values indicating a high d egree of difunctionality.