Thesis (M.Eng.)--Chulalongkorn University, 2002

In this research, effect of catalyst concentration and polymerization temperature on catalyst activity of the ethylene/1-octene copolymerization with ethylenebis(indenyl)zirconium dichloride (Et(Ind)2ZrCl2) catalyst system-trimethylaluminum (TMA) using silica modified with methylaluminoxane (MAO) as support was studied. It was found that the highest catalytic activity was obtained at the catalyst concentration of 5.0x10-5 mole/litre and polymerization temperture of 70 ํC. Subsequently, effect of Al(MAO)/Zr molar ratio and Al(TMA)/Zr molar ratio on catalyst activity of the ethylene/alpha-olefin (1-hexene, 1-octene and 1-decene) copolymerizations with ethylenebis(indenyl)zirconium dichloride (Et(Ind)2ZrCl2) catalyst was investigated by using in-situ supported system (SiO2/MAO) and preformed supported system (SiO2/MAO/Et(Ind)2ZrCl2). It was found that the catalytic activity of the in-situ supported system was higher than that of the preformed supportedsystem in ethylene/alpha-olefin (1-hexene, 1-octene and 1-decene) copolymerizations. Moreover, the results from effect of Al(MAO)/Zr molar ratio on the catalytic activity in both of SiO2/MAO and SiO2/MAO/Et(Ind)2ZrCl2 catalyst system showed the same pattern of an increase of the catalytic activity with increasing of Al(MAO)/Zr mole ratio. On the other hand, the results from effect of Al(TMA)/Zr molar ratio on the catalytic activity exhibited that the pattern of ethylene/1-octene copolymerization in in-situ supported system was different from that of ethylene/1-hexene and ethylene/1-decene copolymerization. While the preformed supported catalyst system indicated the similarity of the pattern of relationship between the catalytic activity and Al(TMA)/Zr molar ratio for all ethylene/alpha-olefin copolymerizations.