Atom Transfer Radical Polymerization of N,N-Dimethylacrylamide

Abstract

The polymerization of N,N-dimethylacrylamide (DMA) under atom transfer radical polymerization (ATRP) conditions was studied. The ligand, solvent (water, n-butanol, and toluene), initiator, and Cu halide were varied. High monomer conversions were obtained using the Me4Cyclam ligand. Polymerizations in water that were initiated at room temperature were complete within minutes. However, none of the experimental conditions produced a controlled polymerization. This conclusion is based on broad molecular weight distributions, poor agreement between theoretical and experimental M n, incremental monomer addition experiments, and end group analysis. We believe that the Cu salts complex to the amide group of the chain ends and stabilize the radical. This stabilization retards the deactivation step in ATRP and produces an unacceptably high concentration of radicals which leads to spontaneous termination reactions. In addition, we have indirect evidence for a cyclization reaction involving nucleophilic Br displacement by the penultimate amide nitrogen; this cyclic onium intermediate undergoes hydrolysis to form a hydroxy-terminated polymer.

Controlled polymerization of (meth)acrylamides by atom transfer radical polymerization

“…A special case is represented by acrylamides, whose reactivity similar to that of acrylates would suggest that they can be easily polymerized by ATRP. However, only partial control of solution polymerization of (meth)acrylamides have been reported [10][11][12][13] . On the other hand, the controlled growth of polyacrylamide films from silica surfaces was claimed [14][15][16] .…”

New Perspectives for the Design of Molecular Actuators: Thermally Induced Collapse of Single Macromolecules from Cylindrical Brushes to Spheres

“…[2] Although ATRP of acrylamides is known to proceed uncontrolled, [10] grafting of NIPAM from planar substrates was reported to yield planar brushes with a high grafting density. [11] However, polymerization of NIPAM in THF at room temperature utilizing the macro initiator always resulted in gel formation.…”

AGET ATRP of Acrylamide in Aqueous Media

“…that it is sufficiently dynamic in order to enable efficient exchange reactions [16]; and, Me 6 TREN is attempted to maintain lower polydispersities level. Furthermore, C-X bond at the chain end will be easily displaced by intra-or intermolecular nucleophilic amide group [17]. Thus, alkyl chlorides rather than bromides are used at relatively low temperatures and low polar solvents, which would reduce relative rates of S N 2 reactions in comparison with the ATRP process.…”