One pot,two step sequence converting atom transfer radical polymerization directly to radical trap-assisted atom transfer radical coupling |
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Authors: | Elizabeth M Carnicom William E CoyneKenneth D Myers Eric S Tillman |
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Affiliation: | Department of Chemistry, Bucknell University, Lewisburg, PA 17837, USA |
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Abstract: | Monobrominated polystyrene (PStBr) chains were prepared using standard atom transfer radical polymerization (ATRP) procedures at 80 °C in THF, with monomer conversions allowed to proceed to approximately 40%. At this time, additional copper catalyst, reducing agent, and ligand were added to the unpurified reaction mixture, and the reaction was allowed to proceed at 50 °C in an atom transfer radical coupling (ATRC) phase. During this phase, polymerization continued to occur as well as coupling; expected due to the substantial amount of residual monomer remaining. This was confirmed using gel permeation chromatography (GPC), which showed increases in molecular weight not matching a simple doubling of the PStBr formed during ATRP, and an increase in monomer conversion after the second phase. When the radical trap 2-methyl-2-nitrosopropane (MNP) was added to the ATRC phase, no further monomer conversion occurred and the resulting product showed a doubling of peak molecular weight (Mp), consistent with a radical trap-assisted ATRC (RTA-ATRC) reaction. |
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Keywords: | Atom transfer radical polymerization Atom transfer radical coupling Polystyrene |
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