文献类型：期刊文献

英文题名：Effect of Mo-modification over Phillips CrOx/SiO2 catalyst for ethylene polymerization

作者：Ma, Yue[1];Cheng, Ruihua[1];Li, Jiajun[1];Zhong, Lei[1];Liu, Zhen[1];He, Xuelian[1];Liu, Boping[1]

机构：[1]E China Univ Sci & Technol, State Key Lab Chem Engn, Shanghai 200237, Peoples R China

年份：2015

卷号：798

起止页码：317

外文期刊名：JOURNAL OF ORGANOMETALLIC CHEMISTRY

收录：;EI(收录号：20152600971679);WOS:【SCI-EXPANDED(收录号:WOS:000357996100043)】；

语种：英文

外文关键词：Ethylene polymerization; Phillips catalyst; CrMo/Si catalyst; TREF

摘要：Phillips CrOx/SiO2 catalyst is an important catalyst for industrial production of polyethylene. In this work, a Mo-modified Phillips catalyst for ethylene polymerization (defined as CrMo/Si) was developed. The characterizations of the Phillips catalyst (defined as Cr/Si) and the CrMo/Si catalyst by temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS) showed an obvious interaction between the chromium and molybdenum components on the silica support. The ethylene polymerization performances at different conditions, in terms of H-2 responds, polymerization temperatures, and the copolymerization with 1-hexene were systematically investigated. Although the polymerization activity of the CrMo/Si catalyst was lower, the copolymer presented a higher molecular weight (MW) and a broader molecular weight distribution (MWD). The Mo-modified Phillips catalyst (CrMo/Si) exhibited 67% higher 1-hexene incorporation ability as determined by C-13 NMR. Moreover, the short chain branch distribution (SCBD) of the copolymer obtained via the CrMo/Si catalyst was also improved as confirmed by temperature rising elution fractionation (TREF) cross successive self-nucleation and annealing (SSA) methods. The results of TREF and SSA showed that the amount of short chain branches for the copolymer was increased in the high MW part, which would benefit for the long term mechanical property of polyethylene. (C) 2015 Published by Elsevier B.V.