DYNAMIC-MECHANICAL BEHAVIOR OF POLY(ETHER ETHER KETONE) POLY(ETHER SULFONE) BLOCK-COPOLYMERS/

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%.