Polymerization and copolymerization of ethylene with higher α-olefins using iron chloride 2,6-bis(imino)pyridyl derivatives-methylaluminoxane catalytic systems

The kinetics of polymerization of ethylene and its copolymerization with 1-octene and 4-methyl-1-pentene catalyzed by four new 2,6-bis(imino)pyridyl iron complexes containing bulky substituents in the ortho position of the aryl ring (R2=cyclopentyl, R3=H, Me, cyclopentyl, R4=H, Me) combined with methylaluminoxane were studied at various temperatures and ethylene pressures. The polymerizing activity of the synthesized complexes was measured in the temperature range 50-80°C and at pressures varying from 0.1 to 0.55 MPa. Using the DSC method, the thermal properties of the samples of PE were determined and their molecular characteristics estimated. A complex with two ortho cyclopentyl substituents was found to exhibit a high thermal stability. The produced polymer samples possess high density (965-972 kg/m3), thus indicating the absence of branching in the macromolecules. The examined catalysts proved to be inactive in the copolymerization of ethylene with 1-octene and 4-methyl-1-pentene.