Simultaneous reversible addition fragmentation chain transfer and ring-opening polymerization

Maude Le Hellaye, Catherine Lefay, Thomas P. Davis, Martina H. Stenzel, Christopher Barner-Kowollik

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The simultaneous ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) and 2-hydroxyethyl methacrylate (HEMA) polymerization via reversible addition fragmentation chain transfer (RAFT) chemistry and the possible access to graft copolymers with degradable and nondegradable segments is investigated. HEMA and ε-CL are reacted in the presence of cyanoisopropyl dithiobenzoate (CPDB) and tin(II) 2-ethylhexanoate (Sn(Oct)2) under typical ROP conditions (T > 100°C) using toluene as the solvent in order to lead to the graft copolymer PHEMA-g-PCL. Graft copolymer formation is evidenced by a combination of size-exclusion chromatography (SEC) and NMR analyses as well as confirmed by the hydrolysis of the PCL segments of the copolymer. With targeted copolymers containing at least 10% weight of PHEMA and relatively small PHEMA backbones (ca. 5,000-10,000 g mol-1) the copolymer grafting density is higher than 90%. The ratio of free HEMA-PCL homopolymer produced during the "one-step" process was found to depend on the HEMA concentration, as well as the half-life time of the radical initiator used.

Original languageEnglish
Pages (from-to)3058-3067
Number of pages10
JournalJournal of Polymer Science, Part A: Polymer Chemistry
Issue number9
Publication statusPublished - 1 May 2008
Externally publishedYes


  • ε-caprolactone
  • 2-hydroxyethyl methacrylate (HEMA)
  • NMR
  • One-step synthesis
  • Reversible addition fragmentation chain transfer (RAFT)
  • Ring-opening polymerization (ROP)

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