Ethylene/1-Hexene Copolymerization over Different Phases Titania-Supported Zirconocene Catalysts

Ethylene/1-hexene copolymerization was performed over titania-supported zirconocene/dMMAO catalysts. Effects of titania having different phases on the catalytic activity and polymer properties were investigated. It was found that anatase titania exhibited the highest catalytic activity, and afforded copolymer with high 1-hexene incorporation among other titanias. According to TGA result, the stronger interaction between dMMAO and titania for anatase phase led to the highest catalytic activity, because the stronger interaction between cocatalyst and support would prevent the leaching of cocatalyst. Additionally, based on EDX mapping, a good dispersion of dMMAO over support surface is another reason for an increase in the catalytic activity. SEM analysis indicated that no significant change in polymer morphology was found for all supported catalysts. The incorporation of 1-hexene determined by C-13 NMR suggested that titania which possessed high amount of [Al](dMMAO) over support surface showed high ability to incorporate 1-hexene. The random copolymers were produced in all systems.