Effect of an added base on (4-cyanopentanoic acid)-4-dithiobenzoate mediated RAFT polymerization in water

Luca Albertin, Martina H. Stenzel, Christopher Barner-Kowollik, Thomas P. Davis

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66 Citations (Scopus)

Abstract

The effect of an added base on the aqueous reversible addition- fragmentation chain transfer polymerization of a methacrylic glycomonomer with (4-cyanopentanoic acid)-4-dithiobenzoate was investigated. When sodium carbonate or sodium bicarbonate were used to dissolve the RAFT agent in aqueous solution at room temperature, an inhibition period of 60-90 min was observed at the beginning of the polymerization together with a marked decrease in the overall polymerization rate. Also, experimental Mn values were much higher than the calculated ones in both cases. When sodium carbonate was used, control over the polymerization process was lost within 43% conversion. Better results were obtained with sodium bicarbonate, in which case the molecular weight distribution remained narrow and unimodal up to 81% conversion. At that point, a higher molecular weight shoulder developed that kept growing in intensity at the proceeding of the reaction. Dramatically improved results were obtained by adding circa 10% ethanol to the polymerization mixture to facilitate the dissolution of (4-cyanopentanoic acid)-4-dithiobenzoate. Following this protocol, narrow polydispersity poly(methyl 6-O-methacryloyl-α-d- glucoside) was obtained possessing a molecular weight close to the predicted value.

Original languageEnglish
Pages (from-to)1011-1019
Number of pages9
JournalPolymer
Volume47
Issue number4
DOIs
Publication statusPublished - 8 Feb 2006
Externally publishedYes

Keywords

  • Aqueous RAFT polymerization
  • Living radical polymerization
  • RAFT agent

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