Living/controlled radical autopolymerization of styrene in the presence of CuCl 2 and 2,2′‐bipyridine

The bulk autopolymerization of styrene (St) was successfully conducted in the presence of CuCl 2 and 2,2′‐bipyridine (bpy) at 110 and 130°C. We found that this polymerization was a living/controlled radical polymerization at a [St] 0 /[CuCl 2 ] 0 /[bpy] 0 ratio of 54:1:2.5. The resulting number‐average molecular weights linearly increased with conversion, and the polydispersity indices were very narrow (<1.5). The polymerization rate increased with temperature. Increasing the ratios (i.e., 129:1:2.5, 259:1:2.5, and 386:1:2.5) led to a decrease in the ability to control the autopolymerization of St, even uncontrolled polymerization (i.e., 643:1:2.5). The analysis of end groups by 1 H‐NMR indicated that the spontaneous generation of radicals from St were generated by a Mayo‐type process, and this living/controlled radical polymerization might have underwent a reverse atom‐transfer radical polymerization process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1532–1538, 2003