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

The glass transition temperatures (T(g)s) and rigid amorphous fraction (X(r)) 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 T(g)s 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 T(g), the X(r) 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 X(r) with PAr composition suggests that the PEEK crystalline becomes less perfect by the addition of PAr in the PEEK-PAr blends. (C) 2000 Elsevier Science Ltd.