LLDPE synthesis via SiO2–Ga-supported zirconocene/MMAO catalyst

In this present study, the linear low-density polyethylene (LLDPE) was synthesized via ethylene/1-octene copolymerization with the zirconocene/MMAO catalyst by in situ impregnation of different silica (SiO2) supports. The SiO2 supports used were small-pored (SP) and large-pored (LP) sizes with and without Ga modification. It was found that the SP-SiO2 support exhibited higher polymerization activity (∼1.5 times) than that obtained from the LP-SiO2 one. This can be attributed to the lower amount of MMAO being present inside the SP-SiO2 support resulting in higher content of MMAO at the external surface. The higher activity in ethylene/1-octene copolymerization was also found with the supported catalyst having Ga modification onto both SP-and LP-SiO2 supports. The results demonstrated that the introduction of Ga may improve ability of supports to immobilize metallocene catalyst. Based on 13C NMR measurement, it indicated that all synthesized polymers were typical LLDPE having random distribution of comonomer.