Thesis (M.Eng.)--Chulalongkorn University, 2012

In this study, the effect of residual trimethylaluminum in methylaluminoxane was studied through catalytic activity of ethylene polymerization. The conditions of support calcination temperatures and SiO₂:MAO molar ratios were first investigated, which the heating temperature at 600 ºC and SiO₂:MAO ratio of 1.5 provided the suitable condition. Afterwards, the MAO having TMA (dried-MAO or dMAO) removed was prepared and reacted with various amounts of TMA. Then, the mixture of dMAO+TMA was impregnated on to the commercial silica support followed by metallocene catalyst. The silica-supported zirconocene/dMAO+TMA was prepared. The activity of ethylene polymerization of residual TMA at 28.6 wt% offered the highest catalytic activity. The reason is that at the amount of TMA less than 28.6 wt% of silica-supported dMAO+TMA, isolated silanol group was observed and when it reacted with metal complex, the catalyst poison was formed. In case of TMA higher than 28.6 wt%, the cocatalyst resulted in the inactive species, which affected on the reduction of catalytic activity.