Long-lived intermediates in reversible addition-fragmentation chain-transfer (RAFT) polymerization generated by γ radiation

Christopher Barner-Kowollik, Philipp Vana, John F. Quinn, Thomas P. Davis

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A novel experimental procedure is presented that allowed probing of reversible addition-fragmentation chain-transfer (RAFT) free-radical polymerizations for long-lived species. The new experimental sequence consisted of gamma irradiation of a mixture of initial RAFT agent (cumyl dithiobenzoate) and monomer at ambient temperature, a subsequent predetermined waiting period without initiation source also at ambient temperature, and then heating of the reaction mixture to a significantly higher temperature. After each sequence step, the monomer conversion and molecular weight distribution were determined, indicating that controlled polymer formation occurs only during the heating period. The results indicated that stable intermediates (either radical or nonradical in nature) are present in such experiments because thermal self-initiation of the monomer can be excluded as the reason for polymer formation.

Original languageEnglish
Pages (from-to)1058-1063
Number of pages6
JournalJournal of Polymer Science, Part A: Polymer Chemistry
Issue number8
Publication statusPublished - 15 Apr 2002
Externally publishedYes


  • Living polymerization
  • Radiation
  • Radical polymerization
  • Reaction intermediates
  • Reversible addition fragmentation chain transfer (RAFT)

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