Preparation and characterization of polyacrylamide in cationic microemulsion

The polymerization of acrylamide in a water/oil cationic microemulsion initiated with a water-soluble radical initiator, potassium persulfate (KPS), was investigated. The kinetics of microemulsion polymerization clearly shows a two-stage process; when the initiator is dissolved in a monomer solution before the emulsification, the reaction rate is higher than it would be if added after the emulsification. The activation energy of the polymerization is affected by the cosurfactant. Information about the microstructures of polyacrylamides is derived from X-ray diffraction, DSC, FTIR, and laser-Raman studies. The results of the studies suggest that the orientation behavior of microemulsion polymerization increases the crystallinity of polyacrylamide and the polar group (-NH2) is coiled in the inner part of the polymer particles compared to solution and water/oil emulsion polymerizations.