Ultrahigh Branching of Main-Chain-Functionalized Polyethylenes by Inverted Insertion Selectivity.

ABSTRACT: Branched polyolefin microstructures resulting from so-called "chain walking" are a fascinating feature of late transition metal catalysts; however, to date it has not been demonstrated how desirable branched polyolefin microstructures can be generated thereby. We demonstrate how highly branched polyethylenes with methyl branches (220 Me/1000 C) exclusively and very high molecular weights (ca. 10⁶  g mol^-1 ), reaching the branch density and microstructure of commercial ethylene-propylene elastomers, can be generated from ethylene alone. At the same time, polar groups on the main chain can be generated by in-chain incorporation of methyl acrylate. Key to this strategy is a novel rigid environment in an α-diimine Pd^II catalyst with a steric constraint that all

SUBMITTER: Zhang Y 

PROVIDER: S-EPMC7496749 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature