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A Novel SiO 2 ‐Supported Cr–V Bimetallic Catalyst Making Polyethylene and Ethylene/1‐Hexene Copolymers with Bimodal Molecular Weight Distribution
Author(s) -
Zhao Ning,
Cheng Ruihua,
He Xuelian,
Liu Zhen,
Liu Boping
Publication year - 2014
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201400094
Subject(s) - catalysis , bimetallic strip , molar mass distribution , ethylene , polymer chemistry , vanadium , polymerization , copolymer , 1 hexene , polyethylene , materials science , polymer , catalyst support , chemical engineering , chemistry , organic chemistry , composite material , metallurgy , engineering
A novel SiO 2 ‐supported Cr–V bimetallic catalyst for ethylene and ethylene/α‐olefin polymerization is investigated. This catalyst is prepared using the residual surface hydroxyl groups in a SiO 2 ‐supported vanadium catalyst to support bis(triphenysilyl) chromate (BC) in order to get the merits from both the vanadium‐based catalyst and the S‐2 catalyst. By investigation of the polymerization behavior and the microstructures of their polymers, several vital factors, such as the addition amount of vanadium species and the dosage of 1‐hexene, on the ethylene/1‐hexene copolymerization are systematically investigated. The results show that the activity of each bimetallic catalyst is higher than that of the S‐2 catalyst, and the product from the bimetallic catalyst shows a higher molecular weight (MW) with a bimodal molecular weight distribution (MWD). The copolymers obtained using the bimetallic catalyst also show a better short‐chain branch distribution (SCBD) than that using the S‐2 catalyst through a temperature rising elution fractionation (TREF) cross successive self‐nucleation and annealing (SSA) characterization.