Chain-end reactivity ratio

{
  "id": "MLC-T-CHM-001854",
  "term": "Chain-end reactivity ratio",
  "field": "Chemistry",
  "definition": "A parameter of the penultimate-unit model of binary copolymerization, defined as k211/k111 for the first monomer (and k122/k222 for the second): how much faster or slower a chain end adds a given monomer when the unit before its terminal unit differs from the terminal unit rather than matching it. A value of 1 means the penultimate unit has no effect. It differs from the monomer reactivity ratio, which compares addition of the same monomer with addition of the other one.",
  "synonyms": [
    "radical reactivity ratio"
  ],
  "subject": "Polymer",
  "see_also": [
    "binary copolymerisation",
    "monomer reactivity ratios",
    "penultimate-unit effect"
  ],
  "references": [
    "PAC, 2008, 80, 2163. 'Glossary of terms related to kinetics, thermodynamics, and mechanisms of polymerization (IUPAC Recommendations 2008)' on page 2168 (https://doi.org/10.1351/pac200880102163)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/chain-end-reactivity-ratio/"
}