Recent Advances in Coordination‐Insertion Copolymerization of Ethylene with Polar Functionalized Comonomers

Abstract

Increasing demand for polar functionalized polyolefins has motivated the development of new polymerization chemistry to introduce functional groups into polyolefins, which is industrially important but scientifically challenging. Coordination-insertion copolymerization of ethylene and polar comonomers offers a direct and economic way to synthesize functionalized polyethylenes and great achievements have been gained by employing catalytic systems based on transition metals and rare earth metals. Continuous efforts have been devoted to developing novel catalytic systems and strategies to introduce chemically diverse functionalities at specific positions, control over the microstructures and get high molecular weight functionalized polyethylenes with high activity and good enchainment capacity. This article summarizes some important advances in the past three years in this field, focusing on the studies using chemically diverse polar comonomers to afford functionalized polyethylenes with novel microstructures.

Efficient Copolymerization of Ethylene with Polar Divinyl Monomer by Phosphino‐Phenolate Nickel Catalyst†

“…[ 3‐7 ] In recent decades, the development of novel catalysts for olefin coordination polymerization, especially late‐ transition metal catalysts represented by nickel‐based and palladium‐based catalysts, has achieved great success in generating various functionalized polyolefins via direct coordination‐insertion copolymerization of olefins with various polar monomers. [ 4,6‐22 ] Focusing on optimizing the structural design of the catalysts, a series of late‐transition metal catalysts by adjusting the steric hindrance effect and electronic effect of ligands have been employed to copolymerize ethylene with a library of polar monomers, such as acrylic acid, [ 23 ] acrylates, [ 7,12,24 ] vinyl fluoride, [ 25 ] acrylonitrile, [ 26 ] vinyl ether, [ 27 ] vinyl trialkoxysilanes, [ 28 ‐ 29 ] and the like. [ 30‐32 ]…”

Titanium Complexes Bearing NNO‐Tridentate Ligands: Highly Active Olefin Polymerization Catalysts with Great Control on Molecular Weight and Distribution†

“…[ 10‐17 ] These non‐metallocene catalysts can show high activity, great control on molecular weight ( M w ) and distribution and produce distinctive polyolefins that are difficult to prepare by heterogeneous catalysts or conventional metallocene catalysts. [ 18‐26 ]…”

Photoresponsive α‐Diimine Nickel Modulated Ethylene (Co)Polymerization†

“…[ 22‐23 ] Notably, the seminal Brookhart's α‐diimine nickel (Ni(II)) and palladium (Pd(II)) catalysts stand out due to the unique chain walking, the functional tolerance, and the ability of copolymerizing polar monomer. [ 24‐30 ] Over the past decades, studies of late transition metal catalysts are mostly focused on the single ligand electronic and/or steric modifications. Although external stimuli, beyond the simple ligand electronic/steric modulation, have been gradually introduced into the design of olefin polymerization catalysts, photoresponsive transition metal catalysts are significantly rare.…”