Preparation method of composite polyacrylamide

The invention provides a preparation method of composite polyacrylamide, and further provides the composite polyacrylamide prepared by the preparation method and application of the composite polyacrylamide as a sewage treatment agent. According to the preparation method provided by the invention, the natural polymer modified chitosan quaternary ammonium salt is innovatively introduced in the polymerization process of the cationic polyacrylamide, so that the composite polyacrylamide of a unitary system is formed, and the cationic polyacrylamide and the chitosan quaternary ammonium salt realize higher water treatment efficiency through a synergistic effect; therefore, the method is especially suitable for sewage and sludge treatment. In addition, due to the use of natural polymers, under the same treatment effect, the dependence on a petroleum route is reduced, and the requirements of low carbon and environmental protection are better met. The composite polyacrylamide provided by the invention is excellent in p