08941 IUPAC Gold Book - chain activation 10.1351/goldbook.08941 08941 current synonyms: activation (in SRMP), unimolecular activation, unimolecular chain activation 1 Unimolecular dissociation of a dormant species to form a mediating agent and a propagating species. In aminoxyl-mediated radical polymerization [nitroxide-mediated polymerization (NMP)], the dormant species is an alkoxyamine and the mediating agent is an aminoxyl radical. In organometallic-mediated radical polymerization (OMRP), the domant species and the mediating agent are organometallic species. In reversible addition-fragmentation radical polymerization (RAFRP), the dormant species is a stable radical and the mediating agent is a non-propagating olefin, e.g., 1,1-diphenylethylene. Chain deactivation (in SRMP) is the reverse of chain activation (in SRMP). Chain deactivation https://goldbook.iupac.org//terms/view/08943 SRMP https://goldbook.iupac.org//terms/view/08921 aminoxyl-mediated radical polymerization https://goldbook.iupac.org//terms/view/08917 dormant species https://goldbook.iupac.org//terms/view/08952 mediating agent https://goldbook.iupac.org//terms/view/08964 organometallic-mediated radical polymerization https://goldbook.iupac.org//terms/view/08920 propagating species https://goldbook.iupac.org//terms/view/08966 reversible addition-fragmentation radical polymerization https://goldbook.iupac.org//terms/view/08922 stable radical https://goldbook.iupac.org//terms/view/08970 PAC, 2022, 94, 1093. 'Terminology for chain polymerization (IUPAC Recommendations 2021)' on page 1117 (https://doi.org/10.1515/pac-2020-1211) https://goldbook.iupac.org/terms/view/08941/html https://goldbook.iupac.org/terms/view/08941/json https://goldbook.iupac.org/terms/view/08941/plain Citation: 'chain activation' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.08941 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-06-21T17:53:06+00:00