Synthesis of styrene/methyl methacrylate gradient copolymer

The gradient copolymer of styrene (St) - methyl methacrylate(MMA) via addition of MMA as a second monomer was prepared by atom transfer radical polymerization (ATRP) at 110 °C promoted by Eib - Br/CuBr/bpy. Controlled relative molecular mass and narrow relative molecular mass distributions proved that the copolymerizations had obvious living characteristics. The unremitting change of copolymer composition through the copolymerization proved that gradient structure was formed. Copolymerization rate and copolymer structure could be influced by copolymerization temperature and addition rate of MMA. Copolymerization rate increased when copolymerization temperature rose or MMA addition rate grew. The relative molecular mass of P(St-t-MMA) could be controlled by the mole ratio of St/Eib-Br.