Polyacrylamide has a wide range of uses in the paper industry, it has different uses according to the different molecular weight , relative molecular weight in 1000 ~ 10000 PAM can be used as dispersant; Polyacrylamide with molecular weight of 500,000 ~ 1 million can be used as reinforcer. Polyacrylamide with relative molecular weight (2 million ~ 4 million) can be used as retention and filtration aid. The relative molecular weight of PAM >7 million is mostly used as flocculant in papermaking wastewater treatment or suspension agent of long fiber pulp paper.
Used as papermaking retention aid filter aid.
it is usually modified products of polyacrylamide, including anionic polyacrylamide (APAM), cationic polyacrylamide (CPAM), the relative molecular weight is between 2 million ~ 4 million. Generally, APAM and other cationic compounds constitute a composite system and play a strong retention role, such as aluminum sulfate combination, can make APAM and fiber, fine fiber, packing, close combination, so as to greatly improve the retention rate of fine fiber and packing. CPAM is one of the most commonly used retention agents in papermaking. Generally, products with high polymer quality and low charge density are used. Its charge is opposite to that of the fiber. It can be used alone or in combination with bentonite and anion to cause the flocculation of the paper material by bridging mechanism, and it can improve the retention rate of the paper filler and reduce the concentration of white water under the net. When CPAM and negatively charged bentonite are used in the particle retention and filtration system, due to the large size of the flocs of the paper material formed by adding CPAM, the flocs are broken into small pieces under the action of high shear force after the grouting pump and other devices, and then the small pieces will be connected again by adding negatively charged bentonite. Moreover, smaller flocs are formed than the initial flocs formed by CPAM. Thus, the retention rate of paper material is improved, and the evenness and water filtration performance of paper are also improved. When AmPAM is used as a retention aid and filter aid, anionic groups repel the anionic waste in the pulp, while cationic groups combine with fibers and fine fibers. Thus, the retention rate of fine fiber was improved.
Reinforcement agent
CPAM used as reinforcement agent, through cation and anion on the fiber to form ionic bond, can make it adsorb to the pulp fiber, and amide group and fiber hydroxyl combination to form hydrogen bond, enhance the binding force between fibers, from how to increase the strength of paper.
Dispersing agent
flocculant polyacrylamide type of dispersant in papermaking industry is relatively low molecular weight cationic polyacrylamide, due to its molecular chain containing carboxyl, negatively charged fiber dispersion effect, can increase the pulp viscosity, is advantageous to the fiber suspension, and can effectively improve the uniformity of sheet, is a kind of highly efficient dispersant of long fiber. And used as a flocculant for water treatment in the paper industry is amphoteric polyacrylamide, its amide group can form hydrogen bonds with many substances in wastewater affinity, so it can be dispersed in the water particles adsorbed together condensed into a group, so as to promote the settlement and filtration of particles.