The less-expensive and earth-abundant nickel catalyst is highly promising in the copolymerization of ethylene with polar monomers and has thus attracted increasing attention in both industry and academia. Herein, we have summarized the recent advancements made in the state-of-the-art nickel catalysts with different types of ligands for ethylene copolymerization and how these modifications influence the catalyst performance, as well as new polymerization modulation strategies. With regard to α-diimine, salicylaldimine/ketoiminato, phosphino-phenolate, phosphine-sulfonate, bisphospnine monoxide, -heterocyclic carbene and other unclassified chelates, the properties of each catalyst and fine modulation of key copolymerization parameters (activity, molecular weight, comonomer incorporation rate, etc.) are revealed in detail. Despite significant achievements, many opportunities and possibilities are yet to be fully addressed, and a brief outlook on the future development and long-standing challenges is provided.
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http://dx.doi.org/10.3390/polym14183809 | DOI Listing |
ACS Macro Lett
December 2024
Department of Polymeric Materials and Engineering, School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China.
In this study, segmented hyperbranched copolymers with degradable and chain extendable cross-linker branch points were synthesized via green light-activated photoiniferter copolymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA) and a trithiocarbonate-derived dimethacrylate. A series of segmented hyperbranched copolymers with different degrees of branching were synthesized by changing the feed ratio of PEGMA to cross-linker to chain transfer agent. The segmented hyperbranched copolymers could be degraded into linear polymer chains by removing the trithocarbonate groups, which provides fundamental insights into the growth of primary chains during photoiniferter copolymerization.
View Article and Find Full Text PDFMacromol Rapid Commun
December 2024
College of Materials Science and Engineering, Nanjing Tech University, Nanjing, 211816, P. R. China.
Deep eutectic solvent (DES)-based eutectogels show significant promise for flexible sensors due to their high ionic conductivity, non-volatility, biocompatibility, and cost-effectiveness. However, achieving tough and stretchable eutectogels is challenging, as the highly polar DES tends to screen noncovalent bonds, such as hydrogen and ionic bonds, between polymer chains, limiting their mechanical strength. In this work, this issue is addressed by leveraging the limited solubility of zwitterionic polymers in a specific DES to induce phase separation, promoting dipole-dipole interactions between polymer chains.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
CNRS - UMR5128 - University of Lyon, 43 av du 11 nov 1918, Villeurbanne, FRANCE.
Polymers (Basel)
November 2024
State Key Laboratory of Chemical Engineering, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310058, China.
This theoretical study investigates the high molecular weight (Mw) production in copolymerization of ethylene and 1-octene using heteroatom-substituted constrained geometry catalysts (CGCs). The research explores the correlation between chain termination reactions and polymer molecular weight, revealing that the Gibbs free energy barrier of the chain termination reactions is positively linked to the molecular weight. Quantitative structure-property relationship models were constructed, indicating that molecular descriptors such as atom charge, orbital energy, and buried volume significantly influence the polymer molecular weight.
View Article and Find Full Text PDFActa Biomater
December 2024
MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310058, China; Center for Healthcare Materials, Shaoxing Institute, Zhejiang University, Shaoxing 312035, China; Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, Hangzhou 310058, China. Electronic address:
Hydrogel microparticles (HMPs) have many advantages for biomedical applications, particularly for minimally invasive therapy, for example, acute lung injury (ALI) that is characterized by high levels of reactive oxygen species (ROS) and pro-inflammatory mediators in the microenvironment. In this study, ROS-scavenging and pro-inflammatory cytokine-neutralizing HMPs were designed and prepared by using a membrane emulsification device. The HMPs were composed of double bond-modified hyaluronic acid and ROS-cleavable hyperbranched poly(acrylate-capped thioketone-containing ethylene glycol) (HBPAK) containing thioketal linkages and unsaturated double bonds.
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