MISCIBILITY AND CRYSTALLIZATION KINETICS FOR THE BLEND OF ISOTACTIC POLYPROPYLENE/ETHYLENE-PROPYLENE RANDOM COPOLYMER

Abstract Miscibility for blends of isotactic polypropylene (PP) and ethylene-D4-propylene random copolymer (EPR)s, which were prepared by copolymerization of propylene and 19 mol% (D-EPR19) and 47 mol% (D-EPR47) of perdeuterated ethylene with metallocene catalyst and then fractionated with a preparative GPC, have been investigated by SANS at various temperatures in the melt. SANS results indicate that most of PP/D-EPR blends are in homogeneous one-phase state in the melt and Flory–Huggins interaction parameter ( χ ) analyzed by random phase approximation are approximately 5.0×10 −3 and less than 1.0×10 −3 for the blends of PP/D-EPR47 and PP/D-EPR19, respectively. Isothermal spherulite growth rate ( G ) for the blends was also measured by optical microscope at various temperatures and the depression of G was observed.