Synthesis and Characterization of Comb-Branched Polyelectrolytes. 1. Preparation of Cationic Macromonomer of 2-(Dimethylamino)ethyl Methacrylate by Atom Transfer Radical Polymerization

The synthesis of water-soluble macromonomers of 2-(dimethylamino)ethyl methacrylate (DMAEMA) by atom transfer radical polymerization (ATRP) was studied in detail. The survival of the unsaturated groups in the initiators during the macromonomer preparation as well as the initiator efficiency depended on the nature of initiator and type of ligand used. The kinetics of the ATRP of DMAEMA catalyzed by allyl 2-bromoisobutyrate (ABIB)/copper bromide (CuBr)/N,N,N‘,N‘,N‘ ‘-pentamethyldiethylenetriamine (PMDETA) system at different conditions indicated that the low initiator efficiency of the ATRP system could not be improved by increasing temperature or changing solvents. It was found that ABIB/CuBr/tris(2-di(butylacrylate)aminoethyl)amine (BA6-TREN) and allyl trichloroacetamide (ATCA)/CuBr/BA6-TREN gave high initiator efficiencies and excellent control over the molecular weights and molecular weight distributions in the ATRP of DMAEMA. 1H NMR studies confirmed that each polyDMAEMA chain had a polymerizable allyl end group. These allyl-terminated polyDMAEMAs after quaternized were proven to be reactive in the copolymerization with acrylamide.