Ultrafast preparation of branched poly(methyl acrylate) (BPMA) with high-molecular weight through single electron transfer living radical polymerization (SET-LRP) of inimer at 25 degrees C has been attempted, atom transfer radical polymerization (ATRP) at 60 degrees C was also carried out for comparison. Gas chromatography, proton nuclear magnetic resonance, and triple detection size exclusion chromatography were used to analyze these polymerizations. As expected, SET-LRP system showed much faster polymerization rate than ATRP system, the calculated apparent propagation rate constants (k(p)(app)) are 3.69 x 10(-2) min(-1) and 6.23 x 10(-3) min(-1) for SET-LRP and ATRP system, respectively. BPMA with high-molecular weight (M-w.MALLS = 86,400 g mol(-1)) compared with that in ATRP (M-w.MALLS = 61,400 g mol(-1)) has been prepared. (C) 2013 Society of Plastics Engineers