Comparison of ethylene polymerization catalyzed over Cr(VI)/silica and Cr(II)/silica catalysts |
| |
Authors: | Chang Soo Kim Seong Ihl Woo Dong Jin Jeong Jun Seok Oh |
| |
Affiliation: | (1) Department of Chemical Engineering, Korea Advanced Institute of Science and Technology, P.O. Box 150, Cheong-Ryang, Seoul, Korea;(2) R and D Center of Daelim Industrial Co., 152, Sin Seong Dong, Yusung Gu, Taejon, Korea |
| |
Abstract: | Summary Ethylene polymerization and the morphology of produced high density polyethylene (HDPE) catalyzed over. Cr(VI)/silica and Cr(II)/silica were studied. Cr/silica catalyst with Cr loading of 1 wt % has been prepared by impregnating an aqueous solution of CrO3 onto silica having specific surface area of 301 m2/g and pore volume of 1.64 ml/g. The rate profiles and the morphologies of polyethylene polymerized over Cr(VI) and Cr(II)/silica were different. The process of active site formation influences the rate profiles. The shape of polyethylene particles polymerized with Cr(II)/silica resembled the original shape of catalyst particles. However, Cr(VI)/silica catalyst particles were fractured inhomogeneously during the polymerization. The variation of molecular weight and molecular weight distribution at various polymerization times indicated that the formation of active sites of Cr(VI)/silica was accomplished gradually during polymerization. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|