文献类型：期刊文献

英文题名：The First Vanadium-Oxide-Based UHMWPE Catalyst Supported on Chemically Modified Silica Gel

作者：Jin, Yulong[1];Cheng, Ruihua[1];He, Xuelian[1];Liu, Zhen[1];Zhao, Ning[1];Liu, Boping[1]

机构：[1]East China Univ Sci & Technol, State Key Lab Chem Engn, Meilong Rd 130, Shanghai 200237, Peoples R China

年份：2017

卷号：218

期号：7

外文期刊名：MACROMOLECULAR CHEMISTRY AND PHYSICS

收录：;EI(收录号：20170703357951);WOS:【SCI-EXPANDED(收录号:WOS:000398603400006)】；

基金：The authors would like to thank the financial support from the National Natural Science Foundation of China (Grant Nos. 21674036 and 21274040) and the Major State Basic Research Development Program of China (Grant No. 2012CB720502). This work was also financially supported by the Fundamental Research Funds for the Central Universities and Research Program of Introducing Talents of Discipline of University (B08021).

语种：英文

外文关键词：chloride-free; modification; polymerization; ultrahigh molecular weight polyethylene (UHMWPE); vanadium-oxide-based catalysts

摘要：Novel vanadium-oxide-based catalysts supported on alumina, zirconia, or titania-modified silica, which are able to synthesize ultrahigh molecular weight polyethylene (UHMWPE), are successfully developed. Compared with the unmodified silica supported catalyst, the activities of the modified catalysts are substantially enhanced. By changing the polymerization temperature (Tp) from 90 to 60 degrees C, the molecular weight of the produced UHMWPE can be easily regulated from 2 x 10(6) to more than 6 x 10(6) g mol(-1). It is the first time that chloride-free nonsingle site catalysts have been developed to synthesize UHMWPE within such a broad range of T-p. Catalyst characterization by NH3-temperature-programmed desorption and pyridine-Fourier transform infrared spectroscopy reveals that the modified catalysts have increased acidity derived from both Lewis and Bronsted acid sites. The X-ray photoelectron spectroscopy characterization indicates that the vanadium on the modified catalysts is more electron deficient. Thus, the acidity of the catalysts and the electronic state of the vanadium play a critical role in determining the activity of the vanadium active sites for ethylene polymerization.