تهیه کاتالیزور زیگلر - ناتا پایه نانوسیلیکا به منظور پلیمریزاسیون پیل اتیلن

Nanosilica was prepared by precipitation method and was characterized by various analytical tools.From transmission electron micrographthe silica particles are found to have almost spherical shape.The surface area is found to be of 271 m2 g−1 anddensity 2.2 g cm−3.The MgCl2/SiO2 hybrid support was prepared by recrystallization method. 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 concentra,on in solid catalyst was 0.95% 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 regula,ng the [Mg]/[Si] ratio and polymerization temperature, and especially when the [Mg]/[Si] ratio was unity, the polydispersity index could be reached over 14.

کلیدواژه ها:

Nanosilica ، TGA ، Ziegler-Natta catalyst ، Polyethylene ، molecular weight distribution