Characterization of isotactic polypropylene obtained with ethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride as catalyst

Polypropylene (PP) prepared with ethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride in conjunction with methylaluminoxane yields 58 wt.-% of material insoluble in boiling heptane (C₇). The C₇-soluble and the C₇-insoluble fraction exhibit high isotacticity, viz. 97,2% and 98,2%, respectively, relatively narrow molecular weight distribution (weight- to number-average molecular weight M?_w/M?_n = 2,19 for the whole polymer), a small amount of regioirregular units arranged with meso-placements and relatively low melting points, i.e., 151,3°C for the C₇-soluble and 153,2°C for the C₇-insoluble fraction in spite of high isotacticity.