Synthesis of star polymethyl acrylate by SET-LRP at ambient temperature

The star-shaped polymethyl acrylate (PMA) was synthesized by single electron transfer living radical polymerization (SET-LRP) at 30 degrees C in dimethyl sulfoxide, using 2,2-dibromomethyl-1,3-dibromopropane as the multifunctional initiator, Cu-0 powder and tris-(2-dimethylamino ethyl) amine (Me-6-TREN) as catalyst. The structure of polymer was analyzed by H-1 NMR, and the results showed that the star-shaped PMA had perfect chain ends (-Br) retention. In addition, the polymerization proceeded smoothly and the time dependence of ln([M](0)/[M]) was linear, which could indicate a first order propagation rate with respect to both radicals and monomer concentration, the polymerization was the living polymerization. The M-n and M-w/M-n of polymer were being measured by Gel Permeation Chromatography. The k(p)(app) = 0.0367 h(-1) and the conversion was 36.3% at 16 h, meanwhile the M-n(GPC) of the polymer was 13,300 and the M-w/M-n was 1.40.