End-functionalised copolymers prepared by the addition-fragmentation chain transfer method: Styrene/methyl methacrylate system

W. Ken Busfield, Clovia I. Zayas-Holdsworth, San H. Thang

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10 Citations (Scopus)

Abstract

Co-oligomers and copolymers of styrene and methyl methacrylate have been prepared by free radical polymerisation in the presence of the chain transfer agent ethyl-α-(t-butanethiomethyl)acrylate. Chain transfer constants are not significantly influenced by the co-monomer composition and lie in the range 0.47-0.90. Bulk copolymer composition is independent of the amount of chain transfer agent in the higher MW range (>20 000). In contrast, the styrene content of lower MW oligomers extracted by fractional precipitation decreases with decreasing MW below about 1000. The efficiency of the addition-fragmentation mechanism in producing specifically end-functionalised co-oligomers (MW<5000) was investigated by 1H n.m.r. spectroscopy. Spectral peaks are mostly consistent with the expected end groups for all co-monomer feed systems. Quantitative consistency of end group concentrations is also good for co-oligomers with MW>1500. At lower MWs, there is an increasing deficiency in olefinic end groups and a high ester group concentration relative to that expected from the MW.

Original languageEnglish
Pages (from-to)389-396
Number of pages8
JournalPolymer
Volume40
Issue number2
DOIs
Publication statusPublished - 1 Jan 1999

Keywords

  • Addition fragmentation
  • Chain transfer
  • End functionality

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