Development of well-defined olefin block (co)polymers achieved by late transition metal catalysts: Catalyst, synthesis and characterization

Abstract

As the saturation rate of the bulk polyolefin market accelerates, the development of high value-added polyolefins becomes increasingly urgent. Particular attention is directed towards advancing olefin block (co)polymers with innovative structures and functions, valued for their exceptional compatibility, mechanical properties, and solubility. The INFUSE from Dow Chemical has achieved significant success in both application market and basic research. Late transition metal catalysts exhibit distinctive advantages in synthesizing olefin block (co)polymers because of their unique chain walking properties. The present contribution outlines the progress achieved in well-defined olefin block (co)polymers using late transition metal catalysts. Categorized by the polymeric monomers, this review extensively summarizes and discusses catalyst structures, synthetic strategies, product features, and characterization methods for the block architecture. Metal complexes (Ni, Pd, Fe, Co, Ru) of α-diimine, amine-imine, amine-pyridine, bis(imino)pyridine, imine-monoxide, allyl-trifluoroacetate, dichloride and alkyl ligands have been employed to synthesize olefin block (co)polymers of ethylene, α-olefins, dienes, and cyclic olefins. Various synthetic strategies, including tandem living polymerization, chain shuttling polymerization, macromolecular cross-metathesis, and macromolecular coupling reaction are concluded. Gel permeation chromatography, nuclear magnetic resonance, and differential scanning calorimetry are frequently used techniques to confirm the block architecture by providing information on molecular weight, chain microstructure, and thermal properties, respectively. These fundamental properties of olefin block (co)polymers are compiled to support their application development. It is envisioned that future research on olefin block (co)polymers should prioritize the development of market-oriented products, which puts forward requirements on product performance characterization and application scenario expansion. Furthermore, investigating the relationship between catalyst structure, polymer microstructure, and product performance will effectively promote the commercialization process.