Abstract: Establishing the relationship between the parameters of modern Ziegler-Natta catalysts (composition, structure and morphology) and the properties (morphology and molecular structure) of polyethylene and ethylene-α-olefins copolymers obtained on these catalysts is an important task, both from a fundamental and practical point of view. In this paper, the influence of a magnesium chloride support on the formation of active centers of Ziegler-Natta catalysts and the regulation of the molecular weight of polymers produced on these catalysts was studied. For this purpose, titanium trichloride (which does not contain a support), massive and supported Ti-Mg catalysts (TMC) of various compositions were prepared. The precursor of the support, unsolvated solid butylmagnesium chloride, the support MgCl2 and TMC were studied by various physical-chemical methods. The catalytic properties of the obtained catalysts were studied in the polymerization of ethylene. Based on the results of X-ray phase analysis, it is concluded that the method of obtaining an MgCl2-containing support affects its structure and the structure of TMCs obtained on its basis. As a result of comparative kinetic studies of catalysts containing only titanium chloride (microspherical TiCl3 and β-TiCl3), as well as massive TMK (TiCl3*nMgCl2) and supported titanium-magnesium catalyst (TiCl4/MgCl2, 1.7 wt% of Ti) in the polymerization of ethylene with different concentrations of hydrogen (polymer chain transfer agent), it was found that the introduction of magnesium chloride into the catalyst composition increases its sensitivity to the regulation of the molecular weight of PE (both in the absence and in the presence of hydrogen).

Cite: Mikenas T.B. , Shloma A.V. , Zakharov V.A. , Matsko M.A.
The Effect of the Support (Magnesium Chloride) on the Regulation of the Molecular Weight of Polyethylene Produced on Titanium-containing Ziegler-type Catalysts
Asian Polyolefin Workshop 2021 20-21 Dec 2021