SYNTHESIS OF MACROCYCLIC ARYL ETHER KETONE SULFONE OLIGOMERS VIA ELECTROPHILIC REACTION AND THEIR THEIR RING-OPENING POLYMERIZATION

Abstract

Under pseudo-high dilution conditions, two kinds of macrocyclic aryl ether ketone sulfone oligomers have been synthesized in high yield from phthaloyl dichloride and electron-rich aromatic hydrocarbons in the presence of Lewis base via electrophilic reaction. The presence of Lewis base NMP in this reaction is demonstrated to be advantageous for forming macrocyclic oligomers. Detailed structural characterization of the oligomers confirmed the cyclic nature by a combination of MALDI-TOF-MS, GPC, IR and H-1-NMR analyses. The cyclic ether ketone sulfone oligomers 3a 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 sulfone) with T-g of 221.8 degrees C and excellent thermal stability. Moreover, the isothermal chemorheology of the ring-opening polymerization of cyclic oligomers 3a was also investigated. The results show that the shear viscosity of the molten reactive mixture increases slowly and is lower than 10 Pa.s at a constant shear rate of 0.05 rad/s in the initial stage of ring-opening polymerization, and the length of the initial stage shortens as the content of initiator Increases.