MELTING BEHAVIOR OF POLY(ETHER ETHER KETONE) IN ITS BLENDS WITH POLY(ETHER IMIDE)

We detail the melting behavior of poly(ether ether ketone) (PEEK) and investigate its melting behavior in miscible blends with poly (ether imide) (PEI). The determination of the equilibrium melting point (T(m)0) of PEEK is discussed by considering its inhomogeneous morphology. T(m)0 is obtained by a long extrapolation of a Hoffman-Weeks plot to 384-degrees-C. Hindrance of PEEK crystal reorganization induced by PEI during heating is observed over the blend composition investigated (20-75 wt % PEEK). This behavior is correlated with the incorporation of PEI in the interlamellar zones of PEEK crystals. The interaction parameter chi of PEEK/PEI blends is estimated by the equilibrium melting point depression. This gives the interaction density B = -1.2 cal/cm3, and chi = -0.40 at 400-degrees-C. (C) 1993 John Wiley & Sons, Inc.