STRUCTURE, CRYSTALLIZATION, AND PROPERTIES OF POLY(ARYL ETHER ETHER KETONE KETONE)S CONTAINING META-PHENYL LINKS AND THEIR COPOLYMERS

Poly(aryl ether ether ketone ketone)s (PEEKK) containing meta-phenyl l inks and their series of copolymers were synthesized and investigated by both X-ray and differential scanning calorimetry (DSC) methods. Res ults showed that the heat properties of this kind of copolymer depende d greatly on the content of meta-phenyl links in the copolymer system, in which occurred the lowest melting point. Results from X-rays showe d that PEEKK containing meta-phenyl links had no (111) crystal face di ffraction. These proved that meta-phenyl links had introduced asymmetr ical factors, which had produced poor crystal structure and difficulty in crystallization. Even so, the modification of PEEKK by introducing the meta-phenyl links improved the polymer composite performances, e. g., the copolymer M(2), which kept performances close to PEEKK but bet ter than PEEK. DSC results of M(2) showed that its Avrami number (n) w as 1.5 and its crystal grew fibrously from isothermal crystallization of the melting state, while for the nonisothermal crystallization from the melting state, n was 4.4 to the spherical crystal growth, and the activation energy (Delta E) of crystallization was 184 kJ/mol, which was less than the Delta E of 296 kJ/mol for PEEKK crystallized from th e nonisothermal melting state. When M(2) was isothermally crystallized from the rubber state, its n was 2 to the disklike crystal growth, wh ile its n was 4.6 to the spherulitic crystal growth for the nonisother mal crystallization state of melting. The isothermal crystallization p rocess was different from the nonisothermal process in the crystal nuc leation and growth for M(2). (C) 1996 John Wiley & Sons, Inc.