NiP^O and [Cp2ZrCl2/MAO] as a versatile dual-function catalyst system for in situ polymerization of ethylene to linear low-density polyethylene (LLDPE)
[Ni(Ph2PCHCOPh)(Ph)(PPh3)] (NiP^O) and Cp2ZrCl2/methylaluminoxane (MAO), well known as ethylene oligomerization and polymerization catalysts, respectively, are combined to produce LLDPE by in situ polymerization. Melting temperature (Tm), degree of crystallinity (χc), intrinsic viscosity, average molecular weight and 13C NMR analysis of copolymers confirm the insertion of α-olefins into the polyethylene chain. Variations in α-olefin concentration and ethylene pressure during the polymerization stage lead to changes in the degree of branching. The resulting copolymers have χc and Tm in the 25.8–65.2% and 114–132 °C ranges, respectively. Experimental results show the versatility of the dual-function catalyst.
Journal: Catalysis Communications - Volume 11, Issue 13, 26 July 2010, Pages 1094–1097