Super absorbent polymer is developing very quickly, species are also increasing, and the source of raw materials is quite rich, because of high water absorbent polymer with hydrophilic groups in the molecular structure, or in the chemical structure of the low degree of crosslinking or partially crystalline structure is not the same, which also formed their own characteristics in some given its high water absorption performance at the same time. From the point of view of the source of raw materials, structural characteristics, performance characteristics, product form and production process, the classification of super absorbent polymer, forming a variety of classification methods.

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With the deepening of the research on the high water absorption polymer, the traditional super absorbent polymer can be classified into starch series, cellulose series and synthetic polymer series. Therefore, Professor Zou Xinxi combined with his own research results, put forward six series of classification.

Starch: starch, carboxymethyl starch, esterified starch, starch xanthate, etc.;

Including: Cellulose Grafted cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, xanthating fiber cable etc.;

Synthetic polymer systems: polyacrylic acid, polyvinyl alcohol, poly (vinyl alcohol), inorganic polymer, etc.;

Protein series: including soy protein, silk protein, gluten, etc.;

Other natural compounds and their derivatives: pectin, alginate, chitosan, heparin, etc.;

Blends and composites: blends of high water absorbent polymer, superabsorbent polymers and inorganic gel complexes, superabsorbent polymers and organic compounds, etc..

Classification according to the hydrophilic method

High water absorbent polymer with hydrophilic chemical groups of the molecular structure of hydrophilic groups, and these greatly affects the super absorbent water retention performance, how to get the structure of these chemical groups in the chemical structure of the superabsorbent polymer effectively, give full play to the point where the hydrophilic chemical group efficiency, has become the focus of Research of high water absorbent polymer now. It can be classified from the hydrophilic method.

Polymerization of hydrophilic monomers (such as polyacrylic acid, polyacrylamide, acrylic acid acrylamide copolymer, etc.);

Hydrophobic (or hydrophilic) polymers, such as carboxymethyl starch (PVA), maleic anhydride (two), and so on;

(hydrophobic or hydrophilic poor) hydrophilic monomer grafted polymer (such as starch graft acrylate, cellulose, starch acrylamide graft acrylic acid salt, starch acrylic acid acrylamide graft copolymer);

The hydrolysis of the amide polymer containing cyano, ester, (such as the hydrolysis of starch grafting acrylonitrile and acrylate vinyl acetate hydrolysis, hydrolysis of polyacrylamide etc.).

Classification by crosslinking

The crosslinking control of super absorbent polymer is an important aspect of controlling the structure of the space. The density of the crosslinking point directly affects the water absorbing and water holding capacity of the super absorbent polymer. Therefore, according to the different ways of formation of the crosslinking points, the following categories can be classified.

Net reaction of crosslinking agent (such as crosslinking agent, water soluble reactive functional groups of polymer and a polyvalent metal ion crosslinked water-soluble polymer, polymer crosslinking agent on water soluble polymer crosslinking etc.);

Self crosslinking reaction (such as self crosslinking polymerization of polyacrylate, polyacrylamide, etc.);

The net reaction (such as polyvinyl alcohol, poly (alkane oxide), etc.) by irradiation;

Water soluble polymers are introduced into hydrophobic or crystalline structures (such as polyacrylic acid and alcohol containing long chain (C12 ~ C20) to obtain insoluble high water absorbent polymer, etc.).

Other classification methods

In the form of product classification, high water absorption polymer can be divided into powder, fiber, film sheet, microspheres, etc..

By the method of preparation, the super absorbent polymer can be divided into synthetic polymer crosslinking, carboxyl methylation, starch graft copolymerization, graft copolymerization of cellulose and so on.

SAP can be divided into non degradable (including acrylic acid, methyl methacrylate and other polymeric products), degradable (including starch, cellulose and other natural polymer graft copolymer products).