Rapid and Highly Efficient Functionalization of Polymer Bromide End-Groups by SET-NRC

A rapid single electron transfer-living radical polymerization (SET-LRP) method using the catalyst Cu(I)Br/Me₆TREN in DMSO to synthesize three arm polystyrene (PS) star in only a few minutes at ambient temperature was reported. The molecular weight of the functionalized polymers is found to increase by 100-700 in accord with the molecular weight of the nitroxide compound. Analysis of the polymer chain-ends after SET-NRC by NMR allowed the determination of chain-end functionality, which was then used to calculate the SET-NRC coupling efficiency. The end-group functionality was calculated based on the integration ratio of methylene protons at 3.63 ppm of PS-Br. The ESI-MS results support the high chain-end functionally from the NRC reaction. The fast and efficient coupling reaction represents a mild, versatile, orthogonal, and highly practical strategy for the functionalization and construction of a wide range of macromolecules.