Glass transition temperatures and rigid amorphous fraction of poly(ether ether ketone) and polyarylate blends

Abstract

The glass transition temperatures (Tgs) and rigid amorphous fraction (Xr) of the poly(ether ether ketone) (PEEK) and polyarylate (PAr) blends prepared by screw extrusion have been investigated by differential scanning calorimetry. From the measured Tgs of PEEK and PAr in the PEEK–PAr blends, Flory–Huggins polymer–polymer interaction parameter (χ12) between PEEK and PAr was calculated and found to be 0.058±0.002 at 360°C. From the measured crystallinity and specific heat increment at Tg, the Xr of PEEK in the PEEK–PAr blends was calculated and found to be 0.31, 0.36, and 0.39 for the pure PEEK, 5:5, and 4:6 PEEK–PAr blends, respectively. The increase of Xr with PAr composition suggests that the PEEK crystalline becomes less perfect by the addition of PAr in the PEEK–PAr blends.