SYNTHESIS AND PROPERTIES OF POLY(ETHER ETHER KETONE) POLY(ETHER SULFONE) BLOCK-COPOLYMERS

Two series of block copolymers composed of poly(ether ether ketone) (PEEK) and poly(ether sulfone) (PES) components were prepared from the corresponding oligomers via a nucleophilic aromatic substitution reaction. In the first series of block copolymers, the M(n)BAR of the PEEK segment was fixed at 10000, while the M(n)BAR of the PES segments ranged from 250 to 9330. (The PES contents of the copolymers varied from 2.2 to 46.2%.) For the other series of block copolymers, the compositions were kept almost constant (PES content approximately 36%), while the segment lengths were changed. Various properties of the copolymers were investigated by differential scanning calorimetry (d.s.c.), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (t.g.a.), and dynamic mechanical analysis (d.m.a.). The results showed that the copolymers exhibited no phase separation and the relationship between the glass transition temperature and the compositions of the copolymers approximately followed the formula, T(g) = T(g1)W1 + T(g2)W2. The crystallization behaviour, thermal properties and dynamic mechanical behaviour of the copolymers were investigated and it was found that both the PES content and the segment length of the copolymers had a significant influence on their crystallization behaviour.