PHASE AND CRYSTALLIZATION BEHAVIOR OF SOLUTION-BLENDED POLY(ETHER ETHER KETONE) AND POLY(ETHER IMIDE)

Results on solution-blended poly(ether ether ketone) (PEEK) and poly(ether imide) (PEI) blends are reported. Dichloroacetic acid was used as the cosolvent for blending. PEEK and PEI are confirmed to be miscible in the melt. The glass transition, T(g), behavior obeys the simple Fox equation or the Gordon-Taylor equation with the adjustable coefficient kappa = 0.86. This agrees with prior data on melt-blended PEEK/PEI blends. The T(g) width of the amorphous PEEK/PEI blends was found to be broader than that of the pure components. The maximum broadening is about 10-degrees-C. The specific volume of the amorphous PEEK/PEI blends shows a slight negative deviation from linearity, indicating favorable interaction between PEEK and PEI. The spherulitic growth and resultant blend morphology at 270-degrees-C were studied by a cross-polarized optical microscope. The radial growth rate of PEEK spherulites formed from the miscible melt at 270-degrees-C decreases from 3.04 mum/min for PEEK/PEI 90/10 blend to 0.77 mum/min for PEEK/PEI 70/30 blend. The decrease in crystalization rate of PEEK from PEEK/PEI blends is attributable to the increase in blend T(g). A linear growth was observed for PEEK spherulites formed from miscible melt at 270-degrees-C in the early growth stage. The spherulitic growth deviated from linearity in the late stage of growth. PEEK spherulites formed from the miscible PEEK/PEI melt at 270-degrees-C are essentially volume-filling. The branches of the spherulites become more clear for PEEK spherulites formed from the blend than that formed from pure PEEK melt.