Abstract: Hydrogel(Water-absorbing polymer) is a new type of polymer chemical material, also known as water-absorbing agent, water-holding agent, water-absorbing polymer, and high-molecular-weight super absorbent resin. It can quickly absorb and maintain hundreds or even thousands of times its own weight in deionized water, dozens to nearly a hundred times the amount of saline, blood or urine, forming a gel-like substance that is difficult to be dehydrated under external force. The reason why the water-retaining agent has high water absorption performance is due to the three-dimensional network structure of ionizing hydrophilic groups such as carboxyl groups. In order to preserve the absorbed water, the water-soluble molecules are lightly cross-linked by an appropriate method to form a network structure inside, and the absorbed water is stored in this structure.Different kinds of water-absorbing polymers

At present, water retention agents at home and abroad can be divided into two categories: one is acrylamide-acrylate copolymer cross-linked products, such as polyacrylamide, potassium polyacrylate, ammonium polyacrylate, sodium polyacrylate, etc., and the other is starch Graft acrylate copolymer cross-linked products, such as starch graft acrylate. Since the water-retaining agent is a super absorbent resin, it contains a large number of structurally specific strong water-absorbing groups, which can produce high-permeability association in the resin and absorb water through its mesh structure. The water-retaining agent can absorb hundreds of its own weight. It is even thousands of times pure water, but the absorbed water cannot be squeezed out, so in addition to strong water absorption properties, the water retaining agent also has strong water retention. The use of water-retaining agents can enhance soil water retention performance, reduce deep water leakage, reduce soil nutrient loss, improve soil structure, and increase water use efficiency.