How Polydadmac(poly diallyldimethylammonium chloride)

Why choose Polydadmac?

As China's papermaking has long been dominated by graminaceous plant fiber raw materials, and herbaceous plant fibers are short, with high content of heterocytes, grass pulp has low retention and poor water filtration in papermaking process.

Polydadmac can improve the problem of lowretention and poor water filtration in the papermaking process, improve productivity and raw material utilization, reduce the cost of tons of paper and environmental pollution. Polydadmac can also improve the water filtration performance of pulp and the formation of paper sheet.

This article investigates the adsorption, retention, and filtration characteristics of Polydadmac with different molecular weights as additives on bleached reed pulp, and get the following conclusion.

1.Adsorption of Polydadmac on Reed Pulp

The smaller molecular weight of the Polydadmac, the greater the decrease in adsorption rate with increasing amount of auxiliary, which may be due to the fact that the smaller the molecular weight of the Polydadmac, the greater ability to catch anions. The less polydadmac is required for the same amount of anion in a saturated system.

2.Filtering effect of Polydadmac

With the increasing dosage of polydadmac, the filtration degree tends to decrease and then increase, and the filtration degree is close to or even exceeds that of the blank when the additive amount reaches and exceeds 0.8%. This means that too much Polydadmac cannot help filtration, but worsens the water filtration of pulp. That means different molecular weight Polydadmac had better filtering effect before they saturated the negative charge on the pulp fiber surface.

3.Retention effect of Polydadmac

As the dosage of Polydadmac increases, the white water concentration of reed pulp gradually decreases first, and then increases again. This investigation indicates that adding polydadmac to reed pulp can significantly improve the retention of short fibers and fine components and raw material utilization, and reduce drainage loads. It was found that the optimal dosage of polydadmac is not affected by their molecular weight; The smaller the molecular weight of the polydadmac, the better the retention effect. But the difference is not obvious, and different molecular weight polydadmac have better retention effects on the surface of saturated pulp fibers before negative charges occur.

Conclusion:

1.Polydadmac with different molecular weights has good filtration and retention effects on reed pulp;
2.Its better filtration and retention effects areachieved when the amount of polydadmac used is less than the negative charge on the surface of saturated pulp fibers;

3.Low molecular weight polydadmac hasgood retention effect.High molecular weight has a good filtering effect. However, there is no significant difference in its effectiveness in assisting filtration and retention.