Thermal and mechanical characterization of partially miscible blends of poly(ether ether ketone) and polyethersulfone

The miscibility behavior of poly(ether ether ketone) (PEEK) and polyethersulfone was studied by differential scanning calorimetry (glass transition temperature) and tensile properties: Young's modulus and ultimate tensile strength. A single glass transition temperature was observed over the entire composition range. The glass transition temperature of blends, however, did not follow any of the theoretical equations. Utracki and Jukes equation was used with K = 11 to fit the experimental data that indicate partial miscibility. Up to 30 wt % PEEK, the blends showed amorphous behavior with the glass transition temperature very close to that of polyethersulfone. Because of partial miscibility, blends showed mechanical compatibility. Both the modulus and strength increased significantly with an increasing concentration of PEEK in the blends, reaching a maximum around 40%. Electron microscopic results revealed phase separation but strong adhesion between the phases.