Species that mediates polymerization in
reversible-deactivation polymerization.
Examples: The aminoxyl radical in aminoxyl-mediated radical polymerization (AMRP) and the RAFT agent in RAFT polymerization.
Source:
PAC, 2022, 94, 1093. 'Terminology for chain polymerization (IUPAC Recommendations 2021)' on page 1124 (https://doi.org/10.1515/pac-2020-1211)