Various elastomeric polypropylenes (PPs) are synthe-

sized through homogeneous propylene polymerization with met-

allocene catalyst (2-PhInd)2ZrCl2 in the presence of different

cocatalyst mixtures: ...

Though preparation procedures of heterogeneous Ziegler-Natta catalysts for propylene polymerization are sophisticated, it is uncertain whether the nature of the active sites is similar or different for different preparation ...