Synthesis and ring-opening polymerization of macrocyclic aryl ketone oligomers

Abstract

A series of macrocyclic aryl ketone oligomers were prepared by the reaction of phthaloyl dichloride or isophthaloyl dichloride with various bridge-linking electron-rich aromatic hydrocarbons 3a-d under pseudo-high dilution conditions in the presence of Lewis base via Friedel-Crafts acylation reaction. Detailed structural characterization of these oligomers confirmed the cyclic nature by a combination of MALDI-TOF-MS, GPC, and 1H NMR analyses. These cyclic ketone oligomers have high solubility in organic solvents and the cyclic oligomers derived from phthaloyl dichloride are amorphous. The cyclic ketone oligomers readily undergo anionic ring-opening polymerization in the melt by using potassium 4,4′-biphenoxide as the initiator, producing linear, high molecular weight poly(ether ketone)s. Moreover, the isothermal chemorheology of the ring-opening polymerization of cyclic oligomers 4a and 4b was also investigated. The results show that the shear viscosity of the molten reactive mixture is lower than 10 Pa S at a constant shear rate of 0.05 rad/sec and increases slowly in the initial stage of ring-opening polymerization. © 2009 John Wiley & Sons, Ltd.