Synthesis And Characteristics Of Chitin/Chtisoan And Their Derivatives

Chitin is the second natural carbohydrate macromolecule in abundance after cellulose. Chitosan is a polysaccharide generally prepared by the N-deacetylation of chitin with alkali. The properties of non-poison and good bio-compatiblity of chitinlchitosan and their derivatives have caused great interest. In this paper, based on the internal and external references, the characteristics se of chitinlchitosan and their derivatives were synthesized7, emphasizing on the chemical modification and their applying. According to the present situation of Hebei province, chitin was extracted from waste crab shells of Qing Huangdao, and then chitosan was prepared. On the base of those, a series of chitin/chitosan derivatives were synthesized and characterized. Finally, ~then they were applied in fruit preservative, flocculation and cosmetics. The main results ~re summerized as follows: (1) Chitosans with low, middle and high viscosity have been prepared from chitin, which was extracted from waste material of crab shells produc ed in Qing HuangDao. Then they were used as fruit preservative. (2) Completely water-soluble chitosans have been prepared whose degr ee of deacetylation is between 40% and 60%, the best one is 50%. Then t hey was used as flocculation agent in dispose of waste water of paper-ma de plant. And its mechanism of flocculation was discussed. (3) Carboxylmethylation of cliitin and chitosans with low, middle and high viscosity has been prepared by one-step method and their all kinds of characteristics were determined such as water solubility, humidity absor ption and thickening to solution. At last, they were used in cosmetics. (4) Chitosans refined with high degree of deacylation were acylated with maleic anhydride in the solvent of formamide, and trisubsitituted prod uct was obtained. Then the product was crosslinked by copolymerization with acrylamide in water solution to obtain gels The times of expansion Iv of the gels were determined in the media of 0.1 M HCL, water and 0.1 M NaOH. (5)Because of excellent properties of moisture obsorption and retentio n of Carboxylmethyl chitirilchitosan, their extents of moisture absorption i s very important in the process of using. Through computer simulation and calculation, extents of moisture absorption under certain relative humi dity can be easily obtained.