Thermal Behavior of Polyethylene Reactor Alloys Polymerized by Ziegler-Natta/Late Transition Metal Hybrid Catalyst.

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 = 0.01, 0.02, 0.04), polymerization temperature (TP = 30, 30-60, 60 °C) and loading temperature (TL = 30, 60 °C) 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 °C and 60-90 °C, 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. [ABSTRACT FROM AUTHOR]