Issue 9, 2021

Tunable branching and living character in ethylene polymerization using “polyethylene glycol sandwich” α-diimine nickel catalysts

Abstract

The secondary coordination interaction that differs from ligand steric and electronic modification is an important tool to modulate the olefin polymerization process. In this contribution, by introducing polyethylene glycol units into the seminal α-diimine framework, a new family of “polyethylene glycol sandwich” α-diimine nickel and palladium catalysts was designed and fully synthesized. The nickel catalysts with varying polyethylene glycol units under the activation of an alkyl aluminum reagent drastically enhanced catalytic activities (up to 9 times) and notably were capable of tuning branching densities of the polymer in ethylene polymerization. With the increase of polyethylene glycol units, the microstructures of polyethylene varied from highly branched (106/1000C) to lightly branched (19/1000C). This corresponded to a conversion from amorphous polyethylene to semi-crystalline polyethylene (Tm = 106.7 °C). The probable “ligand–cocatalyst effect” via the chelation of the oxygen atom in polyethylene glycol units with the aluminum atom in the activator was proposed as a unique secondary coordination interaction. The obtained polyethylenes showed very narrow molecular weights (PDI = 1.01–1.59), and even living polymerization of ethylene was possible. In contrast, under the activation of borate, the palladium analogues showed no activities towards ethylene polymerization.

Graphical abstract: Tunable branching and living character in ethylene polymerization using “polyethylene glycol sandwich” α-diimine nickel catalysts

Supplementary files

Article information

Article type
Paper
Submitted
11 दिसम्बर 2020
Accepted
10 फरवरी 2021
First published
10 फरवरी 2021

Polym. Chem., 2021,12, 1236-1243

Tunable branching and living character in ethylene polymerization using “polyethylene glycol sandwich” α-diimine nickel catalysts

X. Ma, Y. Zhang and Z. Jian, Polym. Chem., 2021, 12, 1236 DOI: 10.1039/D0PY01689F

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements