SAP powder is a new type of functional polymer material, which is widely used in medical and health fields because of its excellent water absorption and water retention. This paper introduces the history and advantages of super absorbent polymer.

1.History of SAP powder

Water absorbing materials have always played an important role in our production and life. Before the 1950s, water absorbent materials used in our production and life were mainly natural products, such as polysaccharides and cellulose. Among them, cotton is the most well-known natural cellulose. There are also some inorganic substances, such as silica gel, calcium oxide and sulfuric acid. However, as water absorbent materials, this kind of materials have insufficient water absorption capacity. Under the action of external forces, such as pressure, it is easy to release absorbed water, which limits the application range of this kind of water absorbent materials. Until the 1960s, new water absorbing materials such as SAP powder gradually developed. This is a high molecular polymer material with three-dimensional network structure, which generally contains hydrophilic groups such as hydroxyl, carboxyl, amino, amido, sulfonic, sulfurous and phosphate groups. It is insoluble in water, can absorb a large amount of water, and can maintain water under pressure and heating conditions.

2.Advantages of SAP powder

Compared with traditional water absorbent materials, SAP powder has the following advantages:

(1) Good water absorption. The water absorption of traditional water absorbing materials can only reach dozens or hundreds of times its own, and its water absorption can reach more than 1000 times its own weight, so its water absorption performance is better.

(2) Strong water retention. Traditional water absorbing materials temporarily absorb water by virtue of their loose porous structure. The water is free in the gap. Under the action of external forces, such as extrusion, centrifugation, etc., the water is easy to be released again. Its molecular chain contains a large number of water absorbing groups, which can combine with water molecules to form hydrogen bonds. Moreover, its physical adsorption can lock a large number of water molecules in the swelling gel network, and it can still maintain water even under conditions such as external force extrusion or heating.

(3) Recyclable. Its swelling can absorb hundreds or even thousands of times its own water, but it is not soluble in solution. After drying the swollen water absorbent resin, it can absorb water again, that is, it can be recycled.

(4) Biocompatibility and microbial degradability. Natural polymers have their unique biocompatibility and degradability. When introduced in its production process, the prepared materials will have biocompatibility and microbial degradability.

These somewhat determine its wide application in life, such as sanitary products, medical dressings, building materials, agriculture, forestry and horticulture.

SAP powder is a kind of polymer material widely used in industry, medical and health fields. Understanding the relevant knowledge of super absorbent polymer is conducive to people to better use this new material.