Jk. Cao et al., SYNTHESIS AND PROPERTIES OF POLY(ETHER ETHER KETONE KETONE)-POLY(ETHER SULFONE) BLOCK-COPOLYMERS, Journal of applied polymer science, 59(6), 1996, pp. 905-914
Poly(ether ether ketone ketone)-poly(ether sulfone) (PEEKK/PES) block
copolymers were prepared from the corresponding oligomers via a nucleo
philic aromatic substitution reaction, and the <(M)over bar(n)> of the
PEEKK segment was fixed at 12,000, while the <(M)over bar(n)>'s of th
e PES segment ranged from 250 to 12,680. The different properties of t
he copolymers were investigated by differential scanning calorimetry (
DSC), wide-angle X-ray diffraction (WAXD), ther mogravimetric analysis
(TGA), and dynamic mechanical analysis (DMA). The results showed that
the relationship between T-g and compositions of copolymers approxima
tely followed the formula 1/T-g = W-1/T-g1 + W-2/T-g2. The PES content
and the segment length of the copolymers had a significant influence
on their melting points and crystallization behavior. The thermal prop
erties and dynamic mechanical behavior of the copolymers were also stu
died. In the study of isothermal crystallization, the copolymers have
the same nucleation mechanism and crystal growth as that of pure PEEKK
. Owing to the introduction of the PES segment into the PEEKK main cha
in, it increases the free energy which forms the critical crystal nucl
eus and produces a resistant action to the whole crystallization proce
ss of the PEEKK segment. (C) 1996 John Wiley & Sons,Inc.