Polymerization of propylene by metallocene and Ziegler-Natta mixed catalytic systems. Study of polypropylene properties

Propylene was polymerized with metallocene and Ziegler-Natta mixed-catalyti c systems to obtain reactor blends of metallocene and Ziegler-Natta-derived propylene homopolymers. The two catalytic systems are able to act jointly, providing individual polymers with different melting and crystallization t emperatures. Compatibility between the components of the mixed-catalytic sy stems and the influence of the components on the polymerization process and on the properties of the reactor blends were studied. Thermal, mechanical, viscoelastic, rheological, and optical properties of the blends were teste d and compared with those of conventional polypropylene grades. (C) 1998 Jo hn Wiley & Sons, Inc.