A facile procedure for controlling monomer sequence distribution in radical chain polymerizations

A novel sequential copolymerization strategy was investigated for preparing macromolecules with programmed sequences of functional comonomers. Four different N-substituted maleimides (N-propyl maleimide, N-benzyl maleimide, N-methyl maleimide, and N-[3,5-bis(trifluoromethyl)phenyl] maleimide) were consecutively added during the atom transfer radical polymerization of styrene performed at 110 degrees C in the presence of a catalyst composed of copper(I) bromide and 4,4'-dinonyl)-2,2'-bipyridine. Owing to the exceptional cross-propagation of N-substituted maleimides with styrene, the four functional comonomers could be sequentially incorporated in the growing polymer chains.