TiCl4 hybridization with modified Ni(II) α-diimine catalyst complex for ethylene polymerization

A hybrid Ni(II) alpha-diimine and conventional TiCl4-based Ziegler-Natta catalyst was synthesized to study the effect of hybridization on the properties of the produced polymer. As the Ti/Ni ratio increased, the catalytic activity decreased due to the steric hindrance of the Ni site, but the deactivation was not severe. The molecular weight distribution showed bimodality in the higher Ti/Ni ratio due to the combined effects of the polymerization of low molecular weight polymers from the Ti-based active sites and the increase in polymer molecular weight from the Ni-based active sites. The polydispersity index (PDI) of the produced PE increased as high as 76, which was 22 times higher than that of the PE polymerized by the pure Ni(II) alpha-diimine catalyst. The melting points of Pas also increased as the Ti/Ni ratio increased due to the contribution of the TiCl4 catalyst.