Method for preparing composite water-retaining agent by adopting plant straws

The invention provides a method for preparing a composite water-retaining agent by adopting plant straws, belonging to the technical field of high-polymer materials. In the invention, the biodegradable plant straws with wide sources and low prices are used as raw materials, and graft copolymerization is carried out on the plant straws and acrylamide, clay, and the like to obtain the composite water-retaining agent with good comprehensive performance, therefore, the cost of the water-retaining agent is effectively reduced, and a new path for the application of the plant straws is sought. Meanwhile, since the composite water-retaining agent also has higher gel strength and saline alkali tolerance, the service performance of the water-retaining agent is further improved, and the service lifethereof is prolonged.