CRYSTALLIZATION STUDY OF POLY(ETHERETHERKETONE) POLY(ETHERIMIDE) BLENDS BY REAL-TIME SMALL-ANGLE X-RAY-SCATTERING/

Morphological changes during isothermal melt crystallization in poly(a ryl ether ether ketone) (PEEK)/poly(ether imide) (PEI, Ultem(R) 1000) blends were monitored via real-time small-angle x-ray scattering (SAXS ) using synchrotron radiation. SAXS data were analyzed using a novel c ombination of correlation and interface distribution functions to dete rmine the lamellar crystal thicknesses l(c) and interlamellar noncryst alline or ''amorphous'' layer thicknesses l(a). The higher glass trans ition noncrystalline PEI component slows the PEEK crystallization subs tantially, but l(a) (about 40 Angstrom) and l(c) (about 85 Angstrom) a re independent of crystallization time and blend composition. This is consistent with the known independence of melting temperature with ble nd composition. These results indicate that PEEK crystallizes in dense ly crystalline lamellar stacks through all stages of primary crystalli zation, and that the noncrystalline PEI is almost entirely excluded fr om the stacks at all times during spherulitic growth. The rate of incr ease in scattering invariant is found to be reduced during spherulite impingement due to spatial limitations.