Reversible addition-fragmentation chain-transfer graft polymerization of styrene: Solid phases for organic and peptide synthesis

Leonie Barner, Nik Zwaneveld, Senake Perera, Yen Pham, Thomas P. Davis

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104 Citations (Scopus)

Abstract

The γ-initiated reversible addition-fragmentation chain-transfer (RAFT)-agent-mediated free-radical graft polymerization of styrene onto a polypropylene solid phase has been performed with cumyl phenyldithioacetate (CPDA). The initial CPDA concentrations range between 1 × 10 -2 and 2 × 10 -3 mol L -1 with dose rates of 0.18, 0.08, 0.07, 0.05, and 0.03 kGy h -1 . The RAFT graft polymerization is compared with the conventional free-radical graft polymerization of styrene onto polypropylene. Both processes show two distinct regimes of grafting: (1) the grafting layer regime, in which the surface is not yet totally covered with polymer chains, and (2) a regime in which a second polymer layer is formed. Here, we hypothesize that the surface is totally covered with polymer chains and that new polymer chains are started by polystyrene radicals from already grafted chains. The grafting ratio of the RAFT-agent-mediated process is controlled via the initial CPDA concentration. The molecular weight of the polystyrene from the solution (PS free ) shows a linear behavior with conversion and has a low polydispersity index. Furthermore, the loading of the grafted solid phase shows a linear relationship with the molecular weight of PS free for both regimes. Regime 2 has a higher loading capacity per molecular weight than regime 1.

Original languageEnglish
Pages (from-to)4180-4192
Number of pages13
JournalJournal of Polymer Science, Part A: Polymer Chemistry
Volume40
Issue number23
DOIs
Publication statusPublished - 10 Oct 2002
Externally publishedYes

Keywords

  • Graft copolymers
  • Living polymerization
  • Radiation
  • Reversible addition-fragmentation chain transfer (RAFT)
  • Solid phase surfaces for combinatorial chemistry

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