| abstract |
Propylene isoblock polymers with 0.5 to 10 mol %, based on the total polymer, of randomly distributed ethylene content and with a narrow molecular weight distribution and rubber-like properties are obtained when propylene is polymerized using a catalyst comprising an aluminoxane and a chiral metallocene, containing bridges, of formula I: ##STR1## in which M 1 is preferably hafnium or zirconium, n R 1 and R 2 are preferably halogen (e.g. C1) atoms, n R 3 through R 6 are hydrogen or C 1 -C 10 alkyl, and pair of adjacent radicals R 3 , R 4 , R 5 , and R 6 can form an aromatic ring with the C-atoms to which they are bonded, and n R 7 is preferably --Si(CH 3 ) 2 --Si(CH 3 ) 2 --. |