Catalytic chain transfer

{
  "id": "MLC-T-CHM-001718",
  "term": "Catalytic chain transfer",
  "field": "Chemistry",
  "definition": "A chain-transfer process in radical polymerization in which a catalyst, typically a cobalt(II) complex, abstracts a hydrogen atom from a propagating radical and then passes it to a monomer. The abstraction leaves a chain with a terminal vinyl group (a macromonomer) and the hydrogen transfer starts a new chain, so molar mass drops sharply at very low catalyst loading. It works best with methacrylates, whose terminal unit carries abstractable hydrogens on its alpha-methyl group.",
  "subject": "Polymer",
  "see_also": [
    "organometallic-mediated radical polymerization",
    "reversible-deactivation radical polymerization"
  ],
  "references": [
    "PAC, 2022, 94, 1093. 'Terminology for chain polymerization (IUPAC Recommendations 2021)' on page 1116 (https://doi.org/10.1515/pac-2020-1211)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/catalytic-chain-transfer/"
}