Abstract:
This thesis involved the preparation of disordered MgCl₂ based support and the optimization of Ziegler-Natta catalysts on magnesium chloride support prepared from magnesium complex. Magnesium complex was prepared by reacting butyloctyl magnesium with 2-ethyl-1-hexanol. The chlorination reaction of magnesium complex was performed with chlorinating agent. It was found that optimum triethylaluminium (TEA)/Mg molar ratio was 0.5. Ziegler-Natta catalyst was synthesized under different Ti/Mg molar ratio using the optimum TEA/Mg molar ratio. The performance of catalyst was evaluated by polyethylene yield under hydrogen pressures of 1 bar and 3 bars. Melt flow index (MFI) of polymers was measured and represented hydrogen response of catalyst. Activity balance (AB) value of the catalyst was calculated. Furthermore, the effect of ethyl benzoate as internal donor (ID) on catalyst property was studied. Amount of Ti and ethyl benzoate fixed on MgCl₂ surface was determined. The higher ethyl benzoate content, the lower Ti amount was fixed on MgCl₂ surface. The property of the catalyst can be further improved by varying post reaction treatment: aging time and aging temperature. It was found that the catalyst was inactive under high hydrogen concentration in polymerization condition if the aging temperature was above 85℃. The replication effect of catalyst morphology on derived polymer particles morphology was shown. It was found that the produced catalyst showed regular shape and did not cause reactor fouling. Molecular weight distribution of polymer produced from this work is similar to that of commercial one.
