SYNTHESIS, PROPERTIES AND CRYSTALLIZATION BEHAVIOR OF POLY(ETHER ETHER KETONE) POLY(PHENOLPHTHALEIN ETHER SULFONE) BLOCK-COPOLYMERS/

Poly(ether ether ketone) (PEEK)/poly(phenolphthalein ether sulfone) (P PES) block copolymers were synthesized by a condensation reaction of f luorine-terminated PEEK oligomers and hydroxy-terminated PPES oligomer s. The content of PPES in the copolymers was varied from 12 to 44 wt.- %, and the effect of the compositional variation on the properties was investigated. Microphase separation was not observed and the copolyme rs formed a homogeneous system having good compatibility. The crystal structure of the copolymers is rhombic, equal to PEEK. The degree of c rystallinity of the copolymers was low and decreased rapidly with the increase of PPES content. Concerning the cell parameters of the crysta lline unit, a- and b-axes are apparently longer and V is, thus, also l arger compared with PEEK. Analyses of the isothermal crystallization k inetics of the copolymers provided an Avrami exponent (n) of 2.0. The glass transition temperature (T-g) of the copolymers greatly rose but the thermal stability became much poorer with the increase of PPES con tent. PEEK/PPES block copolymers possess good mechanical properties su ch as high strength and modulus.