Thesis (M.Eng.)--Chulalongkorn University, 2009

Linear low-density polyethylene (LLDPE) is very important plastic with many applications including package, agricultural film and cable cover. Nowadays, extensive studies have been focused on the use of metallocene as catalyst in the production of LLDPE because of its higher catalytic activity and more uniform molecular weight distribution (MWD) of polymer produced. To use metallocene catalysts used in industrial slurry and gas-phase processes, they have to be heterogenized on supports, which causes the catalytic activity lower than homogeneous metallocenes. As a result, it is important to find a way to attach the metallocene to the support without losing the performance of the homogeneous system. This effort can be achieved by the development of metallocene structure, support and polymerization conditions. In this study, zinc oxide (ZnO) nanoparticles, which are also used as photo-stabilizers in polymer nanocomposites, have been selected as the fillers. LLDPE/ZnO nanocomposites were synthesized via in situ polymerization of ethylene/1-octene with zirconocene/MAO catalyst and the effect of comonomer content on the catalytic activity was investigated and further discussed in more details. It was found that different impregnation methods can alter catalytic activity. In addition, comonomer content also affected polymerization activity. All polymers were further characterized using [superscript 13]C NMR to determine the polymer properties and polymer microstructure.