Species that is formed from an initiator or monomer molecule and that is capable of initiating polymerization.
Notes: - In radical polymerization a primary radical may be formed by the action of heat, irradiation or electron-transfer.
- In radical polymerization, recombination of primary radicals and their reactions with other radicals leads to reduced initiator efficiency.
- The term 'primary species' is also used to designate a species centred on a primary carbon atom, for example, an ethyl radical.
See also: secondary species
Source:
PAC, 2022, 94, 1093. 'Terminology for chain polymerization (IUPAC Recommendations 2021)' on page 1124 (https://doi.org/10.1515/pac-2020-1211)