Design of Bimodal Polyethylene on the Base of bis(imino)pyridine Fe(II) Complexes
A detailed study of the effect of polymerization conditions and co-catalyst composition at the ethylene polymerization over homogeneous and supported LFeCl2 catalysts (where L is unsymmetrical (1) and symmetrical (2) and (3) ligands, see fig 1) on the molecular mass (MM) and MWD of the produced PE is reported. The different activators (MAO, MMAO (methylaluminoxane, modified with Al(iBu)3), MMAO+ Al(iBu)3, DMAO + Al(iBu)3 (DMAO -methylaluminoxane, distilled to remove Al(Me)3), B(C6F5)3+ Al(Me)3, B(C6F5)3+ Al(iBu)3) were used in this study. Data on the noticeable effect of the cocatalyst composition and polymerization conditions on MM and MWD of the PE formed are presented and possible schemes of formation of PE with different MWD are discussed.
It was shown that immobilization of LFeCl2 on SiO2 modified with Al compound leads to formation of highly active and stable supported catalysts with AlR3 as cocatalyst. Data on the control of the produced PE MM and MWD are discussed. An approach for using of different LFeCl2 as components for supported binary catalysts for production of bimodal PE is demonstrated.