THERMAL-PROPERTIES AND CRYSTALLIZATION BEHAVIOR OF POLY(ETHER ETHER KETONE KETONE) POLY(ETHER BIPHENYL ETHER KETONE KETONE) COPOLYMERS

Thermal properties of poly(ether ether ketone ketone) (PEEKK)/poly(eth er biphenyl ether ketone ketone) (PEDEKK) copolymers were investigated by me:ans of differential scanning calorimetry (DSC) and thermogravim etric analysis (TGA). The glass transition temperature (T-g) increases from 154 degrees C to 183 degrees C as the content of PEDEKK units in creases. The melting point (T-m) of the copolymers varied in the range between 314 degrees C and 409 degrees C and showed the behavior of eu tectic type copolymer. From the investigation of the crystallization b ehavior of the copolymers, it was found that the cold-crystallization temperature (T-c') of the amorphous copolymers assumes a maximum value for the copolymer with a mole fraction of the PEDEKK segment (n(B)) o f about 0.6, isothermally crystallized PEEKK and the PEEKK/PEDEKK copo lymer exhibit double-melting behavior.