Copolymerization of n-butyl acrylate with methyl methacrylate and PMMA macromonomers: Comparison of reactivity ratios in conventional and atom transfer radical copolymerization

Both conventional and controlled radical polymerization result in comparable reactivity ratios for low molecular weight monomers where diffusion control is absent. This indicates that the selectivity of the corresponding radicals is independent of the mechanism. The relative reactivity of macromonomers (MM), however, strongly decreases at high concentrations in the conventional radical copolymerization of n-butyl acrylate and polymethyl methacrylate-macromonomer, due to diffusion control. In controlled radical copolymerization a much higher relative reactivity of the MM is observed at these concentrations. This is explained by different time scales for monomer addition leading to the absence or a much later onset of diffusion control in ATRP.