A comparative study of the SET-LRP of oligo(ethylene oxide) methyl ether acrylate in DMSO and in H sub(2)O

A comparative analysis of the SET-LRP of oligo(ethylene oxide) methyl ether acrylate (OEOMEA) in DMSO and in H sub(2)O at 25 degree C is reported. Both the catalysis with activated Cu(0) wire/Me sub(6)-TREN and with mimics of "nascent" Cu(0) nanoparticles/Me sub(6)-TREN resulted in a highe...

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Bibliographic Details
Published in:Polymer chemistry 2012-11, Vol.4 (1), p.144-155
Main Authors: Nguyen, Nga H, Kulis, Jakov, Sun, Hao-Jan, Jia, Zhongfan, van Beusekom, Bart, Levere, Martin E, Wilson, Daniela A, Monteiro, Michael J, Percec, Virgil
Format: Article
Language:English
Subjects:
Acrylates
Disproportionation
Ethers
Monomers
Oxides
Polymerization
Reduction
Wire
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Summary:A comparative analysis of the SET-LRP of oligo(ethylene oxide) methyl ether acrylate (OEOMEA) in DMSO and in H sub(2)O at 25 degree C is reported. Both the catalysis with activated Cu(0) wire/Me sub(6)-TREN and with mimics of "nascent" Cu(0) nanoparticles/Me sub(6)-TREN resulted in a higher rate of polymerization in water than in DMSO. This result is consistent with the acceleration expected for SET-LRP by a more polar reaction solvent, and with the difference between the equilibrium constants of disproportionation of CuBr in DMSO (K sub(d) = 1.4-4.4) and in water (K sub(d) = 10 super(6) to 10 super(7)), both much higher in the presence of Me sub(6)-TREN. The inefficient access of the Cu(0) catalyst to the hydrophobic reactive centers of the monomer and initiator assembled in micellar structures explains the induction time observed in the SET-LRP of OEOMEA in water. This induction period is longer for Cu(0) wire. The use of "nascent" Cu(0) nanoparticles prepared by the disproportionation of CuBr in DMSO, in combination with 5 mol% CuBr sub(2), led to an extremely efficient SET-LRP of OEOMEA in water. This SET-LRP in water is fast and follows first order kinetics to complete monomer conversion with linear dependence of experimental M sub(n) on conversion, and narrow molecular weight distribution. Under the polymerization conditions investigated in both water and DMSO, no reduction in the absorbance of CuBr sub(2)/Me sub(6)-TREN was observed by online UV-vis spectroscopy. This excludes the formation of CuBr by reduction of CuBr sub(2) by Cu(0) during the SET-LRP in DMSO and in water.
ISSN:1759-9954
1759-9962
DOI:10.1039/c2py20782f