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CrV Bimetallic Phillips Catalyst Prepared by Citric Acid‐Assisted Impregnation on Ethylene Polymerization
Author(s) -
Liu Ying,
Zhang Rui,
Ren He,
Liu Yue,
Ling Shijia,
Zhang Hongwei,
Liu Boping,
Cheng Ruihua
Publication year - 2020
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.202000010
Subject(s) - bimetallic strip , ethylene , polyethylene , polymer chemistry , polymerization , catalysis , copolymer , gel permeation chromatography , polymer , necking , chemistry , molar mass distribution , materials science , organic chemistry , composite material
Three CrV bimetallic Phillips catalysts are developed by a citric acid‐assisted impregnation method and studied in ethylene homopolymerization and ethylene/1‐hexene copolymerization. The method benefits to the dispersion of bimetallic active sites, especially for the V ones. The electron binding energy shift of V 2p 3/2 in CrV‐1/2‐CA suggests the increased electron deficiency of V active center. The CrV‐1/2‐CA, CrV‐1/3‐CA catalysts present higher activity, broader molecular weight distribution, than the counterparts without CA‐assisted impregnation, suggesting more active sites involved in the reaction. The 1‐hexene is higher inserted in the polyethylene by CrV‐1/2 than the CrV‐1/2‐CA. But the results of temperature rising elution fractionation‐successive self‐nucleation and annealing (TREF‐SSA) show the thinner platelet thickness at the high molecular weight parts of high‐density polyethylene by CrV‐1/2‐CA, suggesting the higher insertion of 1‐hexene and higher tensile properties. The CrV‐1/2‐CA also shows the more hydrogen‐regulated response in the polymerization. The deconvolution of the gel permeation chromatography curves presents the higher fractions of high molecular weight polymer component.