Mechanism and Dissolution Process of Amphoteric Polyacrylamide As Dispersant

1. The mechanism of action of amphoteric polyacrylamide as a dispersant

The surfactant can make the solid dispersed particles in the suspension be fully wetted and uniformly dispersed by the liquid phase, and minimize the separation and aggregation of the system and the sedimentation speed of the solid particles to maintain the maximum dynamic stability of the suspension. Since the molecular chain of amphoteric polyacrylamide contains carboxyl groups, it has the effect of reducing surface tension and helps water wet solids, which is particularly advantageous for the dispersion of fibers, fillers, etc. in water.

When PAM powder is added to the slurry, it can form a bi-molecular structure on the surface of the fibers and fillers. The outer dispersant has a strong affinity with water, which increases the degree of wetting of solid particles such as fibers and fillers by water. Solid particles such as fibers and fillers are kept away from each other due to electrostatic repulsion to achieve a good dispersion effect.

2. Amphoteric polyacrylamide dissolution process

Although amphoteric polyacrylamide is easily soluble in water, it will form a transparent gel in water and lose fluidity when its dissolved concentration reaches more than 10 per thousand. If a large amount of PAM powder is added instantaneously during the dissolution process, a dissolution system with a concentration greater than 10 per thousand will form in a certain area of the water, making the dissolution process difficult to continue. Therefore, it is necessary to add a certain amount of clean water first, until the stirring blade is covered, start the stirrer to circulate the aqueous solution, and then add the PAM powder.

It is required that the mixing blade should not have corners or blades, otherwise it will produce undesirable effects of hanging materials and shearing the molecular chain of amphoteric polyacrylamide, which will make the dissolved concentration inaccurate and weaken its dispersion effect. The dissolution concentration of amphoteric polyacrylamide should not be too high, generally around 0.5-1 per thousand.