Solvent-free synthesis of polyacrylamide by frontal polymerization
Polymerization and characterization of polyacrylamide prepared by frontal polymerization are described. Frontally polymerized polyacrylamide is imidized and crosslinked during polymerization. Imide formation was determined by elemental analysis. The addition of commercial polyacrylamide or barium carbonate to the monomer (acrylamide) and initiator (potassium persulfate) decreased the reaction temperature from 235 degrees C to < 100 degrees C, thereby reducing imide formation. The commercial polyacrylamide-diluted product, frontally polymerized polyacrylamide-diluted product, and the barium carbonate-diluted product were characterized by IR, TGA, and elemental analysis. Molecular weights of barium carbonate-diluted samples were determined by light scattering and found to be on the order of one million. Conversion of the barium carbonate-diluted product was determined to be 76 +/- 6%, independent of the amount of diluent over the range 0.8:1-1.5:1. (C) 2000 John Wiley & Sons, Inc.