Treatment of the Problem of Viscosity Decrease of Polyacrylamide Solution

To deal with the problem of decreased viscosity of polyacrylamide solution, after polyacrylamide is prepared into a solution, if it is not used in time, the viscosity will decrease when it is used again after a period of time. So what is the reason for the decline? How to deal with it?

For the already produced flocculant polyacrylamide, it is generally impossible to increase the viscosity. Either add a cross-linking agent to partially branch or cross-link it and change its fluid mechanics, which can increase its viscosity to a certain extent.

Generally, the more direct method to increase the viscosity of polyacrylamide is to directly increase its molecular weight. There will naturally be a decrease when there is improvement. Some customers have encountered such problems when using it. The viscosity was inexplicably not up to standard, resulting in less than ideal treatment results. There are many reasons for the decrease in viscosity of flocculant polyacrylamide.

1. Mechanical action. Strong mechanical shearing will break the macromolecules of polyacrylamide, causing its molecular weight to drop too much. Therefore, high-speed mixing will reduce the molecular weight and flocculation performance.

2. Ultraviolet irradiation. Direct irradiation of ultraviolet rays will accelerate the dissolution of oxygen in the flocculant polyacrylamide solution

3. The temperature is too high: Polyacrylamide macromolecules are very sensitive to high-quality chemicals. For example, if a 0.1% polyacrylamide solution is placed at 80°C for 4 hours, the molecular weight will drop from 21 million to 7.6 million, and if it is placed at 50°C, it will also drop to 1600. With a molecular weight of 10,000, the molecular weight dropped to 3.3 million after being placed at 80°C for 4 hours. For example, at 30°C, the molecular weight dropped very slowly. If the original molecular weight of pam is very low, such as 2 million, there will be very little degradation by heat.

5. Degradation reaction. The oxidation reaction generates free ions, which is similar to the effect of ultraviolet irradiation. Care should be taken to avoid this.