Scope for accessing the chain length dependence of the termination rate coefficient for disparate length radicals in acrylate free radical polymerization

Tara M. Lovestead, Thomas P. Davis, Martina H. Stenzel, Christopher Barner-Kowollik

Research output: Contribution to journalArticleResearchpeer-review

7 Citations (Scopus)

Abstract

A method that utilizes reversible addition fragmentation chain transfer (RAFT) chemistry is evaluated on a theoretical basis to deduce the termination rate coefficient for disparate length radicals kt s,l in acrylate free radical polymerization, where sand / represent the arbitrary yet disparate chain lengths from either a "short" or "long" RAFT distribution. The method is based on a previously developed method for elucidation of kt s,l for the model monomer system styrene. The method was expanded to account for intramolecular chain transfer (i.e., the formation of mid-chain radicals via backbiting) and the free radical polymerization kinetic parameters of methyl acrylate. Simulations show that the method's predictive capability is sensitive to the polymerization rate's dependence on monomer concentration, i.e., the virtual monomer reaction order, which varies with the termination rate coefficient's value and chain length dependence. However, attaining the virtual monomer reaction order is a facile process and once known the method developed here that accounts for mid-chain radicals and virtual monomer reaction orders other than one seems robust enough to elucidate the chain length dependence of kt s,l' for the more complex acrylate free radical polymerization.

Original languageEnglish
Pages (from-to)82-93
Number of pages12
JournalMacromolecular Symposia
Volume248
DOIs
Publication statusPublished - 1 Aug 2007
Externally publishedYes

Keywords

  • Backbiting
  • Chain length dependent termination (CLDT)
  • Kinetics
  • Reversible addition fragmentation chain transfer (RAFT)
  • Simulations

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