Thesis (M.Eng.)--Chulalongkorn University, 2013

For polyethylene production, Ziegler-Natta and metallocene catalysts are commonly used for producing polyethylene. The use of metallocene catalyst activated with methylaluminoxane exhibits very high activity in polymerization. Therefore, many studies have been considered to develop and improve the catalytic performance of metallocene catalyst. The study was divided into three parts. Regarding to the first part, the effect of octamethyltetrahydorodibenzo substituent on fluorenyl ligand of CGC catalyst for ethylene/1-hexene copolymerization was investigated. The results show that this substituent on fluorenyl ligand enhanced the activity. The obtained polymer possessed high molecular weight with narrow molecular weight distribution. This is because the substituent increases electron density on active species leading to an increase in the propagation rate. NMR analysis also shows that the octamethyltetrahydorodibenzofluorenyl-ligated complex had the higher 1-hexene incorporation. This complex was found to be an excellent catalyst for ethylene and 1-olefin copolymerization. Thus, the second part was chosen this complex as catalyst and applied it for ethylene and 1-hexene with dicyclopentadiene terpolymerization. It was found that this complex shows high efficient for synthesizing terpolymer. Dicyclopentadiene was found to be a promising alternative termonomer to produce polyolefin containing functional group and offered new polyolefin with specified functions. For the third study, the influence of comonomer chain length in zirconocene system was investigated. The observed results can be divided into two cases; short chain length comonomer and long chain length comonomer. However, comonomer chain length does not significantly affect on the melting temperature and comonomer distribution.