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Title: Branched polyethylenes attainable using thermally enhanced bis(imino)acenaphthene-nickel catalysts: Exploring the effects of temperature and pressure
Authors: Zhang, Q
Zhang, R
Ma, Y
Solan, GA
Liang, T
Sun, WH
First Published: 23-Jan-2019
Publisher: Elsevier
Citation: Applied Catalysis A: General, 2019, 573, pp. 73-86
Abstract: The 4,4′-difluorobenzhydryl-containing nickel(II) bromide and chloride chelates, [1-[2,6-{(4-F-C6H4)2CH}2-4-{C(CH3)3}-C6H2N]-2-(ArN)C2C10H6]NiX2 (X = Br: Ar = 2,6-Me2C6H3 Ni1, 2,6-Et2C6H3 Ni2, 2,6-i-Pr2C6H3 Ni3, 2,4,6-Me3C6H2 Ni4, 2,6-Et2-4-MeC6H2 Ni5 and X = Cl: Ar = 2,6-Me2C6H3 Ni6, 2,6-Et2C6H3 Ni7, 2,6-i-Pr2C6H3 Ni8, 2,4,6-Me3C6H2 Ni9, 2,6-Et2-4-MeC6H2 Ni10), have been prepared and fully characterized. The solid-state structures of representative Ni3 and Ni7 display distorted tetrahedral geometries which are maintained in solution with broad paramagnetically shifted resonances a feature of all the 1H and 19F NMR spectra; the effect the halide (Br/Cl) ligand has on the proton and fluorine chemical shifts presents a further point of interest. All ten nickel complexes displayed, on activation with either MAO (methylaluminoxane) or EASC (ethyl aluminum sesquichloride), very high activities (up to 1.36 × 107 g PE mol−1 (Ni) h−1) for ethylene polymerization at either 1 or 10 atm C2H4 with the structural features of the N,N’-ligand influential. Significantly, with EASC as co-catalyst, Ni5 was capable of operating effectively at 90 °C without comprising too much catalytic activity [ca. 4.34 × 106 g PE mol−1 (Ni) h−1]. All the polyethylenes are highly branched with the branching content and type of branch strongly affected by a combination of temperature, pressure and the class of co-catalyst employed. Moreover, good tensile strength (εb up to 2839.5%) and elastic recovery (up to 74%) have been displayed, properties that are characteristic of thermoplastic elastomers (TPEs).
DOI Link: 10.1016/j.apcata.2019.01.016
ISSN: 0926-860X
Embargo on file until: 23-Jan-2020
Version: Post-print
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2019 Elsevier B.V. After an embargo period this version of the paper will be an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License (, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Description: The file associated with this record is under embargo until 12 months after publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above.
Appears in Collections:Published Articles, Dept. of Chemistry

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