How fast does nonionic polyacrylamide dissolve?

How fast does nonionic polyacrylamide dissolve?

Polyacrylamide is a water-soluble polymer or polyelectrolyte. Because its molecular chain contains a certain number of polar groups, it can adsorb solid particles suspended in water, bridge between particles or neutralize charges. The particles agglomerate to form large flocs, so it can accelerate the sedimentation of the particles in the suspension, and has a very obvious effect of accelerating the clarification of the solution and promoting filtration.

 

1. Diffusion of molecules

The dissolution process of the substance is that the size of the solute molecules is much larger than that of the solvent molecules, so the diffusion rates of the two are very different. Molecules cannot diffuse in the direction of water, so swelling first is a necessary stage of dissolution.

 

2. Hydrogen bonding and entanglement

In the molecular chain and between the molecular chains of non-ionic polyacrylamide, hydrogen bonds can be formed between the amide side groups. Hydrogen bonds are strong intermolecular forces, and there are a large number of hydrogen bonds on the molecular chains of high molecular weight non-ionic polyacrylamide. ; At the same time, the molecular chain of high molecular weight non-ionic polyacrylamide is very long, and the long molecular chain must be curled, and they must be tangled together when they gather together. Therefore, if the non-ionic polyacrylamide accelerates the dissolution, it needs to rely on the rapid penetration and attack of solvent water molecules, net hydrogen bond dissociation and molecular chain dissociation. The dissolution rate of imported polyacrylamide is related to its molecular weight, ionicity, molecular geometry, dissolution temperature, stirring and feeding methods.