Anionic Polyacrylamide: It is the white powder. The APAM with the molecular weight of 5 million-24 million has good water solubility, and it can be dissolved in water by arbitrary proportion but not in organic solvents. It has the characteristics of high-polymer electrolyte in the neutral and alkaline medium, and it is sensitive to the electrolyte salt. And it can be cross-linked into insoluble gel with the high valence metal ions.