ethylene polymerization

This work deals with synthesis, characterization and evaluation of post-metallocene complexes based on silica-supported bis(imino)pyridine iron, containing amino groups in ethylene polymerizations. The reaction of these complexes and methylaluminoxane generated active species in heterogeneous ethylene polymerization. The absence of substituents at the ortho-position of the phenyl rings near the metal site was not compensated by the steric hindrance of the silica surface, negatively affecting the catalytic activity and the molar mass of the produced polymer.

Mixture of two catalysts in one reactor for ethylene/α-olefin copolymerization in the solution process can result in the combination of microstructures related to both catalysts in the polymer framework. Thus, novel polymer configuration is synthesized, which is characterized by containing sequences of monomers produced with each catalyst in the same polymer chain. Adding a reversible transfer agent (CSA) to the binary system enables the production of new block copolymers with enhanced properties.

The asymmetric arylimino pyridine Ni(II) catalysts have been examined with different substituents including diisopropyl, diethyl, fluoro, and chloro groups. The influence of these substituents and variation of ethylene pressure on the catalytic activity, crystalline structure, as well as on thermal properties of polyethylene has been investigated.