Poly (aryl ether ether ketone ketone) (PEEKK) is a kind important high-performance polymers due to their excellent thermal stability and other outstanding properties similar to PEEK and PEKK．However

the PEEKK’Sinsolubility in common solutions and high melt point restrict its processing and applications．In this paper

a series of random eopolymers composed of poly(aryl ether ether ketone ketone)(PEEKK)/poly(aryl ether ketone ether ketone ketone) containing bis(o-metheyl) moiety (DM-PEKEKK) were prepared by low temperature solution polyeondensation of 4

4'-bis(2

6-dimethylphenoxy) diphenylketone (o-M2DPOBP)

1

4-dipheoxylbenzene(DPB) and terephthaloyl ehlorde(TPC) in 1

2-diehloroethane with the presence of AlCl3 and DMF．The copolymers were characterized by FT-IR

DSC

WAXD

TGA

etc．The results show that glass transition temperature increases greatly with the increasing of the ratio of o-M2DPOBP/DPB

while melting temperature and erystallinity of copolymers decrease．The solubility of the eopolymers is improved greatly

while the eopolymers still exhibit excellent thermostability．