Yc. Ke et al., STRUCTURE, CRYSTALLIZATION, AND PROPERTIES OF POLY(ARYL ETHER ETHER KETONE KETONE)S CONTAINING META-PHENYL LINKS AND THEIR COPOLYMERS, Journal of applied polymer science, 61(8), 1996, pp. 1293-1303
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.