Polyacrylamide is a kind of linear water-soluble polymer. When the concentration is appropriate, polyacrylamide aqueous solution can be regarded as a molecular chain forming a network structure in water, and has a certain polarity factor. It can well adsorb suspended particles in water, and form large precipitates through the network structure, which has a good effect of accelerating precipitation and filtration.

After adding appropriate amount of polyacrylamide into water, due to its characteristics, it generally takes 15-30 minutes to completely dissolve. The high viscosity and strong toughness of the dissolved aqueous solution are mainly determined by the molecular characteristics of polyacrylamide. As a high molecular polymer, the higher the molecular weight, the higher the viscosity of the aqueous solution. Molecular weight is the length of molecular chain. The larger the molecular weight is, the denser the network structure in water is, and the greater the viscosity of aqueous solution will be. The viscosity of polyacrylamide aqueous solution will decrease with the increase of aqueous solution temperature, mainly because high temperature will destroy the network structure of polyacrylamide aqueous solution. The lower the network structure, the lower the viscosity of aqueous solution. Therefore, the water solution of polyacrylamide should be prepared at a suitable temperature.

The higher the viscosity of polyacrylamide solution is, the better the effect of water treatment is. When selecting polyacrylamide, the larger the molecular weight is, the better.