GLASS-TRANSITION, CRYSTALLIZATION, AND MORPHOLOGY RELATIONSHIPS IN MISCIBLE POLY(ARYL ETHER KETONES) AND POLY(ETHER IMIDE) BLENDS

The relationships among glass transition, crystallization, melting, an d crystal morphology of poly(aryl ether ketone) (PAEK) /poly(ether imi de) (PEI) blends was studied by thermal, optical and small-angle x-ray scattering (SAXS) methods. Two types of PAEK were chosen for this wor k: poly (aryl ether ether ketone), PEEK, and poly (aryl ether ketone k etone), PEKK, which have distinctly different crystallization rates. B oth PAEKs show complete miscibility with PEI in the amorphous phase. A s PAEK crystallizes, the noncrystallizable PEI component is rejected f rom the crystalline region, resulting in a broad amorphous population, which was indicated by the broadening and the increase of T(g) over t hat of the purely amorphous mixture. The presence of the PEI component significantly decreases the bulk crystallization and crystal growth r ate of PAEK, but the equilibrium melting temperature and crystal surfa ce free energies are not affected. The morphology of the PEI segregati on was investigated by SAXS measurements. The results indicated that t he inter (lamellar-bundle) PEI trapping morphology was dominant in the PEEK/PEI blends under rapid crystallization conditions, whereas the i nterspherulitic morphology was dominant in the slow crystallizing PEKK /PEI blends. These morphologies were qualitatively explained by the ex pression delta = D / G, where G was the crystal growth rate and D was the mutual diffusion coefficient.