Polyacrylamide (PAM) is an important multifunctional polymer material with many excellent physical and chemical properties. In this article, we will introduce the structure, synthesis method, application field and environmental impact of polyacrylamide.
Polyacrylamide is obtained by polymerization of acrylamide monomer. It is a linear or cross-linked polymer compound with the following general structural formula:
ch2─ch(conh2)]n ─
where n represents the degree of aggregation, i.e., the number of repeating units.
There are many methods for the synthesis of polyacrylamide, among which the commonly used methods include free radical polymerization, ionic polymerization, and initiation polymerization.
Free radical polymerization is one of the most common synthesis methods. The main steps include: mixing the acrylamide monomer with initiators, solvents, etc., and heating to a certain temperature; The monomer molecule is activated by the addition of an initiator, which gradually polymerizes into a polymer.
Ionic polymerization is the application of high-energy radiation or chemical initiators to initiate monomer polymerization reactions. Among them, high-energy radiation polymerization methods include -ray irradiation, electron beam irradiation, and ultraviolet irradiation.
Initiation polymerization is the polymerization of acrylamide monomers by initiators under the action of light or heat. This method is a fast and efficient synthesis method.
Polyacrylamide has a wide range of applications in the field of industrial production and scientific research, with the following main fields:
1) Water treatment: Polyacrylamide is widely used in sewage treatment, sludge dewatering, deep desalination treatment and drinking water purification. It can be used as an organic polymerization coagulant, which can effectively remove suspended solids, color, colloids and organic matter in water.
2) Petroleum exploitation: As an oilfield chemical, polyacrylamide can be applied to water injection treatment, slow-release plugging agent and enhanced oil recovery.
3) Textile industry: polyacrylamide can be used as a coating agent, printing auxiliary, and fiber dyeing agent for textiles.
4) Agriculture: Polyacrylamide can be used as a soil retention agent, granular soil amendment and soil and water conservation straw curtain, etc., and plays an important role in farmland soil and water conservation, landscape and desert management.
Polyacrylamide has a certain environmental impact, which is mainly reflected in the following aspects:
1) Water environment: Undecomposed polyacrylamide will form colloidal substances in water, which has a certain impact on the transparency and water quality of the water body. In addition, the high molecular weight of polyacrylamide can lead to precipitation during the water treatment process, which can cause clogging of water treatment equipment.
2) Biological toxicity: High concentrations of polyacrylamide have certain toxicity to certain microorganisms and aquatic organisms. Therefore, care needs to be taken to control its concentration during use to reduce the impact on the environment.
3) Decomposition products: Polyacrylamide will produce acrylamide monomers and acrylamide polymers during the decomposition process, and these products have certain toxic potential. Therefore, it is necessary to take appropriate treatment measures when dealing with polyacrylamide waste and using expired products.
In summary, polyacrylamide is an important multifunctional polymer material with a wide range of applications. During use, care needs to be taken to control its concentration and dispose of waste liquid and expired products to reduce the impact on the environment.