Organo-cobalt mediated living radical polymerization of vinyl acetate
Journal
Macromolecules
Journal Volume
41
Journal Issue
7
Pages
2368-2373
Date Issued
2008
Author(s)
Abstract
Vinyl acetate polymerization initiated by azo radical sources in the presence of cobalt(II) tetramesitylporphyrin ((TMP)CoII) shows an induction period followed by an organo-cobalt mediated living radical polymerization (LRP). The induction period corresponds to converting (TMP)CoII to an organo-cobalt porphyrin derivative (organo-Co(TMP)). Living character at low vinyl acetate conversion is demonstrated by a linear increase in molecular weight with conversion, relatively low polydispersity homopolymers, and formation of block copolymers with methyl acrylate ((TMP)Co-PVAc-b-PMA). Deviations from ideal LRP occur by radical termination and chain transfer events at moderate conversion of vinyl acetate (VAc). Mechanistic studies demonstrate that the VAc radical polymerization is controlled by a degenerative transfer mechanism that utilizes organo-cobalt complexes as the transfer agent. Kinetic studies are utilized in comparing radical polymerization of vinyl acetate and methyl acrylate that are mediated by organo-cobalt complexes. ? 2008 American Chemical Society.
Other Subjects
Living radical polymerization (LRP);Vinyl acetate;Free radical polymerization;Living polymerization;Vinyl resins
Type
journal article