Water absorbent resin is a widely used functional polymer material. After water absorption and expansion, how to quickly degrade it to reduce its pollution to the ecological environment has become one of the hot spots of scholars at home and abroad. This paper briefly introduces the biodegradation mechanism of absorbent polymer.
The biodegradation of water absorbent resin is a relatively complex process, which carries out physical and chemical reactions under the action of organisms, most of which are fungi, bacteria and molds. There are three main biodegradation mechanisms:
(1) Physical function of organism, which is the mechanical destruction of substances caused by the growth of biological cells;
(2) The chemical action of organism, and the microorganisms that oxidize and hydrolyze water absorbent resin produce new substances;
(3) With the direct action of biology, some macromolecular polymers can be decomposed by enzymes produced by microorganisms' own metabolism, which can be converted into small molecular substances for degradation.
It has complex biodegradation mechanism. Biodegradation mechanism is the result of the joint action of various mechanisms.
The biodegradability of water absorbent resin is mainly affected by chemical structure and environmental conditions.
The relationship between biodegradability and chemical structure is as follows: (1) Most absorbent polymers with natural polymer structure are biodegradable. (2) It takes the C-C bond as the main chain for addition. When the relative molecular weight exceeds 1500, biodegradation cannot be carried out, and when the relative molecular weight is lower than 1500, biodegradation can be carried out. (3) When containing hydrophilic groups, such as -nh2.-cooh and -oh, it can improve the hydrophilicity of polymers, provide appropriate humidity environment for organisms, and make polymers easier to hydrolyze and biodegrade. (4) Amorphous polymers are easier to hydrolyze than crystalline polymers. When the activity of the chain increases, the free volume of the molecule will also increase. The greater the possibility of enzyme attack, the easier it will be degraded. (5) The higher the relative molecular weight, the worse the biodegradability, and the biodegradability of polymers will also be affected by CO mixing and other factors.
In addition, environmental factors such as water temperature, pH value and oxygen will also affect the biodegradability of polymer.
As a functional polymer material, water absorbent resin can maintain excellent water absorption performance under pressure, so it has been widely used in industry, life and other fields. Understanding the biodegradation mechanism of absorbent polymer is conducive to the better application of this material.