Abstract: PEKK/PESEKK copolymers of high molecular weight have been synthesized by solution polycondensation of diphenyl ether, terephthaloyl chloride and 4,4'-diphenyoxydiphenyl sulfone in a catalyst/solvent system of AlCl₃/ClCH₂CH₂Cl/NMP. The effects of monomer molarity and reaction time on copolymer molecular weight are studied. The copolymers have been characterized by IR, DSC and WAXD. The results indicate that the copolymers exhibit excellent heat-resistance. Raising PESEKK content in the copolymer increases the T_g of the copolymer, but decreases its T_m and crystallinity. The elongation at break of the copolymer is much higher than that of PEKK, but the tensile modulus and tensile strength are lower than those of PEKK.

Key words: poly(ether ketone ketone)/poly(ether sulfone ether ketone ketone)copolymer, synthesis, thermal property, mechanical property