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 M_w/M_n = 1.32. The initiation mechanism of BPO is different from that of AIBN because there is redox reaction between BPO and Cu^I generated from the reaction of radicals with Cu^II. The initiation mechanism of BPO/Cu^IICl₂/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.