Effect of bimodal silica-alumina-supported metallocene catalyst for ethylene/α-olefin copolymerization

Abstract

Nowadays, metallocene catalyst becomes to be more interesting in an olefin polymerization. Therefore, it has led to extensive efforts to utilize metallocene catalysts efficiently. The homogeneous metallocene catalysts have two major disadvantages; (i) the lack of morphology control and (ii) reactor fouling. Supporting metallocene catalysts onto inorganic supports as supported metallocene catalysts can solve these problems. This research proposed the development and improvement of metallocene catalyst, such as the rac-Et(Ind)₂ZᵣCl₂/dMMAO system, by using silica-based supports with different pore structures such as unimodal pore (large pore and small pore) and bimodal pore. These studies were divided into two parts. In the first part, impact of different supported zirconocene/dMMAO on the catalytic activities during copolymerization of ethylene/1-octene was investigated. The largest amount of [Al][subscript dMMAO] on the support as confirmed by the EDX measurement and the fewer interaction between dMMAO and the support as proven by the TGA analysis apparently resulted in dramatically increased polymerization activity for the large pore silica gel [SiO₂ (LP)]. In the second part, the impact of α-olefins (1-hexene, 1-octene and 1-decene) employed under the corresponding condition as mentioned in the first part was further investigated. It was found that different α-olefins can alter the polymerization activities upon different supports used. All the obtained polymers were characterized by DSC and ¹³C NMR to determine the polymer properties and polymer microstructure.