Irradiation degradation of polysaccharide polymer material sodium alginate

　　Sodium alginate is the sodium salt of natural polymer material alginic acid, and its molecular formula is (C6H7O6Na) n. The human body can't absorb sodium alginate with large molecular weight, but when the molecular weight of sodium alginate is reduced to a certain range, it can be easily absorbed by the human body. It can be used to treat hyperlipidemia, coronary heart disease and hypertension, and can be used as a plasma substitute. It is a good dilatant for maintaining blood volume, and also shows excellent antibacterial, hygroscopic and moisturizing properties.

　　At present, the price of low molecular weight sodium alginate is relatively high, and only a small amount of sodium alginate is used in China, which is not commensurate with the extensive use of sodium alginate and the rich resources of sodium alginate in China. If we can develop a practical, efficient and environmentally friendly method for degrading sodium alginate, it will bring considerable economic and social benefits. The existing industrial degradation process of polysaccharide polymer materials is mainly acid -catalyzed degradation. Acid-catalyzed degradation is to use polysaccharide polymer materials to easily react with acids and break glycoside bonds to a chieve the purpose of degradation. The process is complicated, and a large number of acid and alkali solutions are used, which causes certain pollution to the environment and has certain influence on the quality of products.

　　In order to solve these problems, many research groups at home and abroad focus on developing new low-pollution or pollution-free degradation methods, the most prominent of which are radiation degradation and biodegradation. Both methods have the characteristics of fast degradation and light pollutio n. Biodegradation has been widely studied because of its high degradation efficiency and low one-time manufacturing cost, but the separation of biological enzymes after biodegradation is still a difficult problem to be solved, which greatly affects the quality of degradation products and the popularization of this technology. Radiation degradation has attracted much attentio n because of its fast degradation, simple process before degradation and easy recovery of degraded products. This study uses γ Sodium alginate was degraded by irradiation device, and the changes of absolute molecular weight and its distribution before and after irradiation were tested and analyzed by means of MALLS/GPC, a system connecting multi-angle laser light scattering instrument and gel permeation chromatograph.

　　Through the analysis of 60Co&gamma of high molecular weight sodium alginate; The study of radiation degradation shows that in aqueous solution environment, radiation can effectively degrade sodium alginate, reduce the average molecular weight of sodium alginate and reduce the molecular weight distribution width. When the absorbed dose is 40~60kGy, the weight average molecular weight of sodium alginate is below 15000, and the weight average molecular weight in the peak area of its molecular weight distribution is below 10000, which can be well absorbed by human body and has excellent medical and health care functions. It is worth mentioning that the solvent used in this stu dy is pure water, and there is no acid-base pollution in the collection process of sodium alginate after irradiation, which is beneficial to the environment and sustainable development of industrial production.

　　In addition, in the process of irradiation, in addition to sodium alginate with different polymerization degrees, a small amount of new components are also produced. These new components need to be separated and purified, and their molecular structures should be determined to identify whether they are biologically harmful. If the new components are not harmful to human body, radiation degradation is a preparation method of low molecular weight sodium alginate which is worth popularizing.