SYNTHESIS AND CHARACTERIZATION OF PHTHALAZINONE POLY(ARYL ETHER SULFONE KETONE)WITH CARBONYL GROUP*

 A kind of novel heat-resistant, high performance engineering thermoplastic phthalazinone poly(aryl ether sulfoneketone) (PPESK) containing a carboxyl group in its side chain was prepared by the nucleophilic displacement reaction of 4-(4-hydroxylphenyl)-1(2H)-phthalazinone with di(4-chlorophenyl) sulfone, 4,4'-difluoro-benzophenone and phenolphthalin insulfolane in the presence of K₂CO₃ to produce high molecular weight polymers which can be dissolved in some polar solvents such as chloroform and nitrobenzene at room temperature and can be easily cast into flexible,yellowish and transparent films.PPESK is an amorphous polymer having a decomposition temperature above 400℃,which indicates that it has high thermal staility.At the same time,the thermal properties of PPESKs with dicyandiamide (DICY) as curing agent indicated that the heat-resistance properties of the PPESKs are improved after curing.The apparent activation energy(△E) of the cross-linking reaction and the reaction order(n) of PPESK/DICY were found to be 52.2 kJ/mol and ca.1.0,respectively.Therefore,the cross-linking reaction is approximately a first order reaction.