New aromatic poly(ether-ketone)s containing hexafluoroisopropylidene groups

New aromatic poly(ether-ketone)s containing hexafluoroisopropylidene groups have been prepared by aromatic nucleophylic displacement reaction of the p otassium salts of aromatic dihydroxy compounds containing fluoren, 1,3,4-ox adiazole or phenylquinoxaline rings with 2,2-bis[4-(4-fluorobenzoylphenyl)h exafluoropropane. These polymers were readily soluble in various organic so lvents such as N,N-dimethylformamide, pyridine, tetrahydrofuran and chlorof orm and gave flexible films by casting such solutions. Their glass transiti on temperatures (T-g) were in the range of 189-222 degreesC and they were t hermally stable up to 480 degreesC. The polymer films displayed low dielect ric constants, in the range of 2.8-3.2, and good mechanical properties, wit h tensile strength in the range of 46-61 MPa and elastic modulus of 1.4-1.6 GPa.