A series of high molecular weight alternative and random poly(aryl ether ketone ketone) copolymers were prepared by low-temperature solution poly-condensation

with 1

4-bis(4-phenoxybenzoyl)benzene (p-EKKE)

1

3bis(4-phenoxybenzoyl)benzene (m-EKKE)

diphenyl ether (DPE) and terephthaloyl chloride (TPC) or isophthaloyl chloride (IPC)

respectively.The inherent viscosities (ηnh) of resulting copolymers were in the range of 0.63～1.08 dL/g.The chemical structure of p-EKKE

m-EKKE and PEKKs were confirmed by FT-IR.The thermal properties of copolymers were obtained by DSC and TG. The DSC results indicated that the melt temperature (Tm) and the glass transition temperature (Tg) decreased with increasing the amount of meta-phenylene substituted in the main chain. The TG results showed that the copolymers had excellent thermooxidative stability

being stable above 530℃

which was affected slightly by the amount of meta-phenylene substituted in the main chain.The alternative copolymer b-PEKK has better order and higher crystallinity than random copolymers.WAXD showed that copolymer p-PEKK and its model compound had the same crystallization diffraction spectra corresponding to a rhombic system.While the morphology of the copolymer i-PEKK and the corresponding model compound showed needle crystals

which belonged to an anorthic system.i-PEKK was difficult to crystallize again in the course of melting

and it was in an amorphous state.