Jk. Cao et al., DYNAMIC-MECHANICAL BEHAVIOR OF POLY(ETHER ETHER KETONE) POLY(ETHER SULFONE) BLOCK-COPOLYMERS/, Macromolecular chemistry and physics, 197(4), 1996, pp. 1495-1502
Poly(ether ether ketone) (PEEK)/poly(ether sulfone) (PES) block copoly
mers were synthesized via condensation reaction between fluorine-termi
nated PEEK oligomers and hydroxyl-terminated PES oligomers. The dynami
c mechanical behavior of a composite sample prepared by compression mo
lding of a glass fibre cloth and the copolymer was investigated by mea
ns of a dynamic viscoelastometer. The beta relaxation peak and the alp
ha' relaxation peak were observed in the logarithmic decrement curve o
f the amorphous block copolymer of PEEK/PES. The glass transition temp
erature (beta relaxation peak) is shifted to higher temperature and ap
proaches a constant value as annealing time and degree of crystallinit
y increase. The glass transition temperature of the copolymer rises mo
re slowly upon annealing with increasing PES content. The alpha' relax
ation peak becomes smaller upon annealing, and eventually disappears.
The alpha' relaxation peaks are related to the motion of molecules upo
n transition from the non-crystalline to the crystalline state. The al
pha' relaxation occurs for the coplymer with a degree of crystallinity
of 0 to 3%.