Reverse atom transfer radical polymerization of dimethyl itaconate initiated by a new azo initiator: AIBME

Reverse atom transfer radical polymerization (RATRP) was used to synthesize poly(dimethyl itaconate) (PDMI) using an AIBME/CuBr2/dNbpy system. The number average molecular weight (M-n) of PDMI was as high as M-n = 15 000 g mol(-1), the monomer conversion rate reached up to 70%, and the dispersity remained low (D = 1.06-1.38). The first-order kinetics of PDMI are discussed in detail. The AIBME initiator had a higher initiation efficiency than the AIBN initiator. As the ratio of initiator (AIBME) to catalyst (CuBr2) decreased, the M-n and D of PDMI decreased. At 60 degrees C and 80 degrees C, the M-n of PDMI was much higher than the theoretical number average (M-n,M-th), and the D of PDMI broadened with the conversion rate. At 100 degrees C, the D of PDMI remained low, and the M-n of PDMI was closer to the M-n,M-th. As the ratio of monomer (DMI) to initiator (AIBME) increased, the M-n of PDMI changed little over time. These phenomena could be explained by the influence of the initiator and catalyst on polymerization kinetics.