RAFT polymerization with phthalimidomethyl trithiocarbonates or xanthates. On the origin of bimodal molecular weight distributions in living radical polymerization

Almar Postma, Thomas P. Davis, Guoxin Li, Graeme Moad, Michael S. O'Shea

Research output: Contribution to journalArticleResearchpeer-review

165 Citations (Scopus)

Abstract

Phthalimidomethyl trithiocarbonate reversible addition-fragmentation chain transfer (RAFT) agents are effective in imparting living characteristics to radical polymerizations of butyl acrylate (BA) and N-isopropylacrylamide (NIPAM) and provide a route to end-functional polymers with predictable_molecular weight and narrow molecular weight distributions (e.g., number-average molecular weight for PBA (M̄n) = 21 300 and polydispersity (M̄w/M̄n) = 1.1 at 96% conversion). End group determination suggests that bimodal molecular weight distributions and long chain branches in PBA arise by copolymerization of a PBA macromonomer formed by backbiting β-scission. The S-phthalimidomethyl xanthates provide good control over polymerizations of the less-activated monomers N-vinylpyrrolidone (NVP) and vinyl acetate (VAc). In the case of PBA with a trithiocarbonate end or PVAc with a xanthate end, the C-S bond to the thiocarbonylthio end group can be homolyzed by thermolysis at > 180°C leaving the phthalimidomethyl end group and the ester side groups intact providing macromonomers, with ω end group -CH2-C(CO2C4H9)(=CH 2) or -CH2-C(O2CCH3)(=CH 2) respectively, as the main products.

Original languageEnglish
Pages (from-to)5307-5318
Number of pages12
JournalMacromolecules
Volume39
Issue number16
DOIs
Publication statusPublished - 8 Aug 2006

Cite this