Synthesis and Characterization of Low Molecular Weight Ethylene-Propylene Copolymers Prepared Using Metallocene Catalysts

The synthesis in a liquid propene phase of ethylene–propylene copolymers of low molecular weights (3 000–20 000 g mol−1) is accomplished using three different metallocenes containing bridged bis(indenyl) moieties: (A) rac‐dimethylsilylbis(4,5,6,7‐tetrahydro‐1‐indenyl)zirconium dichloride, (B) rac‐ethylenebis(4,5,6,7‐tetrahydro‐1‐indenyl)zirconium dichloride, and (C) rac‐ethylenebis(indenyl)zirconium dichloride. Hydrogen pressures higher than 1 bar were required to drop the molecular weight below 25 000 g mol−1. Metallocene B gives rise to the copolymers with lower molecular weights (