Abstract
ABA type block copolymers of ethylene and propylene, where the central B block is a random copolymer of ethylene and propylene and the A blocks are isotactic polypropylene, are prepared in addition to ethylene-propylene random copolymers. A dry catalyst system of TiCl3(AA)-Et2AlCl and a gas-phase polymerization technique were used for the preparation of copolymers. Thermal and dynamic mechanical behavior of ethylene-propylene block copolymers are described with respect to the relationships between structure and property. The results from thermal analysis and dynamic mechanical analysis demonstrated that the EP random copolymers developed the 'blocky'nature. The block architecture as well as monomer composition was demonstrated as an important factor in determining the physical and mechanical properties of ABA type ethylene-propylene block copolymers.
