Cyclic etherketones

The propensity of this bisphenol to form high yields of cyclic macromers exhibits itself in the condensation reaction of i with 4,4 -dihalo substituted diphenylketones and diphenylsulfones to produce cyclic etherketones and ethersulfones. Polymerization of the polyarylate, polyetherketone and polyethersulfone macromers can also be accomplished in the presence of anionic initiators to produce linear polymers. 

Macrocyclic oligomer precursors of polycarbonates, PET, polymers of amides, etherketones, and ethersulfones are candidates for further study of macrocyclic oligomer polymerization thermodynamics [6]. Research extends to cyclic arylates (cyclic aryl-aryl esters) and cyclic alkyl aryl esters going back to isolating a cyclic trimer of poly(ethylene-terephthalate) in 1954 [13]. Much of the work on macrocyclic oligomers as precursors to high-MW macromolecules starts with spiro(bis)indane (SBI) biphenyl monomer to produce macrocyclic carbonates. 

Like the ether and thioetherimides, the ethersulfone and etherketone cyclics are activated toward ring-opening polymerization via transetherification. Heating of the cyclic oligomer mixture at 380-400° C in the melt with 1.0 mol% of bisphenol A disodium salt produced a polyethersulfone having a wt. avg. MW of about 80,000. Polymerization of the etherketone cyclics has not yet been reported. 

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