Author/Authors :
Ahmadi، Ebrahim نويسنده Department of chemistry, University of Zanjan, P.O. Box 45195-313, Zanjan, Iran , , Mohamadnia، Zahra نويسنده , , Rahimi، Sajjad نويسنده Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, Iran , , Armanmehr، Mohammad Hasan نويسنده Department of Chemical Technologies, Iranian Research Organization for Science and Technology, P.O. Box 15815-3538, Tehran, Iran , , Heydari، Mohammad Hossein نويسنده Department of chemistry, University of Zanjan, P.O. Box 45195-313, Zanjan, Iran , , Razmjoo، Mahmood نويسنده Department of chemistry, University of Zanjan, P.O. Box 45195-313, Zanjan, Iran ,
Abstract :
Ethylene polymerization was carried out using Phillips chromium catalyst based on silica supports such as silica
aerogel, SiO2 (Grace 643), and titanium modified SiO2 (G 643), and the results were compared with other
catalysts based on SiO2 (Aldrich), SBA-15(Hex), SBA-15(Sp) and MCM-41. A combination of TGA, DSC, XRD,
nitrogen adsorption, SEM, ICP, FTIR and other analyses were used to characterize the materials. The results showed
that the chromium was successfully introduced into silica supports. Shish-kebab polyethylene was prepared via in situ
ethylene polymerization with the Cr/SiO2 (G 643) and Cr/Ti/SiO2 (G 643) catalytic systems. A comparison between
different types of catalysts revealed that the polymerization activity of Cr/SiO2 (G 643) was significantly increased to
191 kg PE (g Cr)-1 h-1 due to the higher pore volume and pore diameter of Grace silica compared to the other supports.
Also, the polymerization activity of the Cr/SiO2 (G 643) catalyst was significantly improved by Ti-modification.
Polyolefins
