STUDIES ON THE FUSION HEAT OF POLY(ETHER ETHER KETONE KETONE)-POLY(ETHER BIPHENYL ETHER KETONE KETONE) COPOLYMERS

On the basis of DSC measurements, the Delta H-f(0) values of the fusio n heat for PEEKK-PEBEKK copolymers with various biphenyl contents were obtained by using thermodynamics statistical theory proposed by Flory and graphical method of the specific volume-fusion heat. The results reveal that Delta H-f(0) values determined by these two methods for PE EKK-PEBEKK copolymers with various biphenyl content are nearly the sam e, and that Delta H-f(0) values are closely dependent on biphenyl cont ent. Delta H-f(0) value is minimum at n(B)=0.35.