Preparation of Bi-supported Ziegler-Natta catalysts of MgCl2/SiO2 for Ethylene polymerization

A novel MgCl2/SiO2-supported Ziegler-Natta catalyst was synthesized. Slurry polymerization of ethylene was carried out using the catalyst in dry hexane, while; TEA was used as cocatalyst. The cocatalysts effects, such as cocatalyst/catalyst molar ratio, H2 concentration, polymerization temperature and monomer pressure on activity of the catalyst were investigated. Ti concentration in solid catalyst was 0.86% wt. Structural study was carried out using FTIR, SEM, XRF,GPC and BET techniques. It was found that the polydispersity index of polyethylene could be adjusted over a wide range of 2-15 through regulating the [Mg]/[Si] ratio and polymerization temperature, and especially when the [Mg]/[Si] ratio was unity, the polydispersity index could be reached over 14. The results showed the addition of hydrogen caused to decrease the activity of catalyst, while; increasing monomer pressure caused to have an increase in activity.