Accessing chain length dependent termination rate coefficients of Methyl Methacrylate (MMA) via the Reversible Addition Fragmentation Chain Transfer (RAFT) process

Geoffrey Johnston-Hall, Alexander Theis, Michael J. Monteiro, Thomas P. Davis, Martina H. Stenzel, Christopher Barner-Kowollik

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76 Citations (Scopus)

Abstract

The RAFT-CLD-T methodology is demonstrated to be not only applicable to 1-substituted monomers such as styrene and acrylates, but also to 1,1 -disubstituted monomers such as MMA. The chain length of the terminating macromolecules is controlled by CPDB in MMA bulk free radical polymerization at 80°C. The evolution of the chain length dependent termination rate coefficient, kti,i, was constructed in a step-wise fashion, since the MMA/CPDB system displays hybrid behavior (between conventional and living free radical polymerization) resulting in initial high molecular weight polymers formed at low RAFT agent concentrations. The obtained CLD of kt in MMA polymerizations is compatible with the composite model for chain length dependent termination. For the initial chain-length regime, up to a degree of polymerization of 100, kt decreases with a (in the expression kti,i = kt 0·) being close to 0.65 at 80°C. At chain lengths exceeding 100, the decrease is less pronounced (affording an α of 0.15 at 80°C). However, the data are best represented by a continuously decreasing nonlinear functionality implying a chain length dependent aα.

Original languageEnglish
Pages (from-to)2047-2053
Number of pages7
JournalMacromolecular Chemistry and Physics
Volume206
Issue number20
DOIs
Publication statusPublished - 24 Oct 2005
Externally publishedYes

Keywords

  • Kinetics
  • Living polymerization
  • Methyl methacrylate
  • Reversible addition fragmentation chain transfer polymerization (RAFT)
  • Termination rate coefficient

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