Preparation of carboxyl‐end‐group polyacrylamide with low polydispersity by ATRP initiated with chloroacetic acid

Atom transfer radical polymerization (ATRP) of acrylamide was successfully carried out with chloroacetic acid as initiator and CuCl/N,N,N',N'-tetramethylethylenediamine (TMEDA) as catalyst either in water at 80 °C or in glycerol-water (1:1 v/v) medium at 130 °C. In both cases, carboxyl-end-group polyacrylamide was obtained with lower polydispersity ranging from 1.03 to 1.44 depending on the polymerization condition. Polymerization kinetics showed that the polymerizations proceeded with a living/controlled nature and accelerated at a higher temperature. The effect of pH in the reaction system on the polymerizations was further studied, revealing that chloroacetic acid not only served as a functional initiator for the ATRP of acrylamde but also provided the acidic polymerization condition, which effectively protected the ATRP of acrylamide from the unexpected complexation and cyclization side-reactions.