Reserse atom transfer radical polymerization of styrene using BPO as the initiator under heterogeneous conditions

Reverse atom transfer radical polymerization of styrene in the presence of a conventional radical initiator (benzoylperoxide, BPO) in bulk was successfully implemented via a new polymerization procedure. The system first reacts at 70°C for ten hours, then polymerizes at 110°C, which results in a well-controlled radical polymerization with high initiation efficiency and narrow molecular weight distribution of the resulting polymer, i. e., the polydispersity is as low as Mw/Mn = 1.32. The initiation mechanism of BPO is different from that of AIBN because there is redox reaction between BPO and CuI generated from the reaction of radicals with CuII. The initiation mechanism of BPO/CuIICl2/bpy is deduced through the experimental data. The molecular weight of the resultant polymer is in agreement with the theoretical value calculated in accordance with the aforementioned mechanism.