FORMATION OF AROMATIC POLYETHERKETONE AND TRANSETHERIFICATION OF AROMATIC POLYETHERKETONE

High molecular weight aromatic polyetherketone (PEK) was found to react with 4,4'-difluorobenzophenone (DFB) in the presence of potassium carbonate in benzophenone or diphenyl sulfone at 300-degrees-C, yielding low molecular weight PEK with fluorophenyl end groups, while neither polyetheretherketone (PEEK) nor poly-thioetheretherketoneketone was found to react under similar conditions. Reaction model experiments showed that 4-fluorobenzophenone reacts with potassium carbonate at 300-degrees-C to yield benzoyldiphenyl ether and that benzoyldiphenyl ether undergoes spontaneous trans-etherification in the presence of potassium carbonate at 300-degrees-C. These results indicate that the overall reaction yielding PEK of reduced molecular weight consists essentially of DFB oligomerization followed by trans-etherification between the DFB oligomer and PEK.