In the process of paper forming, paper fibers and fillers in pulp are hydrophobic and tend to be flocculated into clumps.It is necessary to add a kind of assistant to increase the viscosity of paper pulp, to facilitate the uniform dispersing of fiber and filler, to make the paper form uniformly smooth and flexible without holes, to make the paper performance stable, not easy to cut paper and powder, and at the same time to improve the tensile strength and dry and wet strength of paper and save pulp.These additives are called paper dispersants.
In most people's impression, polyacrylamide is mainly used in the water treatment field. However, with its extensive application in the industry in recent years, there is no small achievement in the paper industry. Both as a dispersant and a retention and filtration agent, polyacrylamide has been widely used as a substitute for other paper additives products.This paper aims to introduce the mechanism of polyacrylamide as a dispersant for paper making.
Polyacrylamide is commonly used as a dispersant as its sodium salt.As the carboxyl group contained in the molecular chain has a dispersing effect on negatively charged cellulose fiber, and when the relative molecular weight is about 17 million, it can improve the slurry viscosity, which is conducive to fiber suspension. Therefore, this product is a high-efficient dispersing agent of long fiber.
Its molecular structure is as follows:
Its dispersion principle by polyacrylamide molecular chain containing carboxyl, have the function of the lower surface and, help water wetting of solid, packing and so on in the water for the fiber dispersion special advantage, when PAM to join slurry, can make the molecular structure of fiber and filler surface double, outer dispersant extremely strong affinity with water and increase the fiber, filler and other solid wetting by water molecules.The solid particles such as fiber and filler are far away from each other due to the electrostatic repulsion and achieve good dispersion effect.