Supported ziegler-natta catalyst prepared from magnesium ethyl carbonate for ethylene polymerization

Abstract

This work focused on the preparation and optimum condition for active MgCl2 based support. The reactant magnesium ethyl carbonate was prepared by reacting magnesium ethoxide with carbon dioxide in ethanol as medium. The chlorination reaction was introduced with ethyl aluminium sesquichloride (Al2Et3Cl3) as chlorinating agent. The suitable molar ratio of Al2Et3Cl3/Mg was found to be 0.5. Ziegler-Natta catalyst was synthesized under different Ti/Mg molar ratios. The performance of catalyst was evaluated for ethylene polymerization under hydrogen pressure of 1 bar and 3 bars. Melt flow rates (MFR) of polymers were measured and represented hydrogen response of catalyst. The property of catalyst can be further improved by heat treatment (varying temperature and time). The suitable heat treatment temperature was 110oC. It was found that high molecular weight polyethylene was produced using long heat treatment time. The effect of ethyl benzoate to the preparation of catalyst was studied. The experimental results showed that the catalysts demonstrated highly balanced hydrogen response and activity (AB) suitable for bimodal HDPE. Dicyclopentyl dimethoxysilane (DCPDMS) added while preparing MgCl2 supports was supposed to act as binding agent and was found to improve the morphology and increase the average particle size of polymer. Molecular weight distribution of polymer produced from this work is broader than of a commercial one. The polyethylene has a spherical shape.