POLY 179 |
| Cobalt porphyrin derivatives are observed to participate in the control of living radical polymerization (LRP) by two distinctly different mechanisms. Cobalt (II) porphyrin (Co(II)) metallo-radicals mediate a LRP by reacting with polymeric radical (P•) to produce a quasi-equilibrium with an organometallic complex (Co-P) which gives living character through the persistent radical effect. Diamagnetic organo-cobalt complexes in combination with an additional radical source such as AIBN and V-70 produce an alternate form of LRP. The rates of polymerization by the organo-cobalt mediated route are relatively fast and approach that of regular radical polymerization because the radical concentration is determined by the organic radical source. Radical polymerizations of acrylic acid and vinyl acetate mediated by the organo-cobalt porphyrins route are used in illustrating the principal mechanistic features of this process. |
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General Papers: Synthesis and Characterization
6:00 PM-8:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster
Division of Polymer Chemistry |