A Ziegler-Natta/metallocene composite catalyst(MgCl2/TiCl4/rac-Et(Ind)2ZrCl2)of reactor granule technology characteristics is combined with a co-catalyst pair of triethylaluminum (AlEt3

TEA) and methyaluminoxane (MAO) to activate its Ti and Zr catalytic species respectively.TEA exhibits a deactivating effect on the Zr species amid propylene homopolymerization

whereas ethylene restores the deactivated species during ethylene-propylene copolymeriation.By this way

a reversible deactivation of the metallocene Zr species has been realized in the preparation of catalyzed polypropylene alloys(propylene homopolymerization + ethylene-propylene copolymerization) with Ziegler-Natta/metallocene composite catalyst.New catalyzed polypropylene alloys have been prepared with MgCl2/TiCl4/rac-Et(Ind)2ZrCl2composite catalyst and TEA/MAO bi-component co-catalyst

with the catalyst and co-catalyst added in one-pot.The polypropylene (PP) matrix is selectively produced by the Ziegler-Natta Ti species

while the ethylene-propylene copolymer (EPR) is accounted for in large portion by the metallocene Zr species.Compared to conventional Ziegler-Natta catalysts

the Ziegler-Natta/metallocene composite catalyst renders PP alloys with a more random sequence distribution and equally well domain distribution of EPR.This research provides a new route to the controlled preparation of catalyzed PP alloys.