Nickel diimine late transition metal (LTM) and Cp 2 TiCl 2 metallocene catalysts were supported on the TIBA-modified MgCl 2 ÁnEtOH adduct, separately and concurrently, at different ratios, to yield hybrid catalysts, where the catalytic precursors were activated in the ethylene polymerization with TEA as the cocatalyst. Polymerization activities revealed that supported LTM catalysts show very high levels of activity, in an adverse trend with polymerization temperature ranging from 30 to 70°C, in opposition to the activity of metallocene component. Consequently, the proportion of corresponding polymer fractions were tuned by changing reaction temperature as well as catalyst composition. Study of thermal properties confirmed that LTM component is responsible for production of less crystallizable branched chains, while metallocene fraction makes highly crystallizable linear chains. All samples showed noticeable thermorheological complexity due to coexistence of linear and branched microstructures. Interestingly, it was found that increase in metallocene fraction of the hybrid catalyst stalls the terminal relaxation of the produced polymers and increases the entanglement density by decreasing the extent of branching. Study of dynamic mechanical properties revealed that the intensity of b transition could be correlated with the branching level and catalyst composition accordingly.

Polyethylene reactor alloys are synthesized through heterogeneous ethylene polymerization with a new type of Ziegler-Natta (ZN)/late transition metal (LTM) hybrid catalyst. The effect of various parameters including catalyst composition (LTM/ZN ¼ 0.01, 0.02, 0.04), polymerization temperature (TP ¼ 30, 30-60, 60 8C) and loading temperature (TL ¼ 30, 60 8C) on catalyst activity, chain's vinyl content, viscosity average molecular weight (M v ) and thermal properties are investigated. Two distinct melting peaks were observed in the ranges of 110-140 8C and 60-90 8C, indicating presence of two different lamellar structures. LTM/ZN ratio shifted melting peaks toward lower values. Rheological properties confirmed homogeneity of polymer blend's microstructure as they follow time temperature superposition.Macromol. React. Eng. 2015, 9, 8-18 wileyonlinelibrary.com PolymerizationCatalyst component handling and polymerization procedures were carried out as previously described. [47] Polymerization reactions were performed in a 150 ml steel reactor equipped with controlling Scheme 1. Structure of late transition metal catalyst.