Preparation And Application Of Water-soluble Chitosan

In this work, two process of chitosan degradation was investigated: (1). with hydrogen peroxide under the irradiation of ultraviolet light; (2).with hydrogen peroxide under the catalysis of phosphotungstic acid in chitosan-water heterogeneous system. By the solution self-organization, two kinds of organic-inorganic complexes of phosphotungstic acid with chitosan and chitosans degraded were prepared. Their primary antibacterial activity was studied.The optimal preparation condition of water-solubility chitosan was studied by ultraviolet light -hydrogen peroxide. The effect of the mass fraction of hydrogen peroxide, chitosan, acetic acid and irradiation time on the degradation was discussed. The optimal preparation condition of water-solubility chitosan was studied with hydrogen peroxide under the catalysis of phosphotungstic acid in chitosan-water heterogeneous system, the effect of concentration of hydrogen peroxide , reaction temperature and time, dosage of catalyst on the degradation was discussed. The structure of the degraded product was characterized by Fourier transform infrared spectra analysis and diffuse reflectance spectra analysis. Two mechanism of the degradation of chitosan was studied. The experimental results show that water-solubility chitosan can be effectively produced by two degrading methods. The chitosan degraded exhibited the essential structural characteristics of chitosan. The optimum reaction condition of chitosan degradation with hydrogen peroxide under irradiation with ultraviolet light was obtained as follows: irradiation time 1h, the mass fraction of hydrogen peroxide, chitosan, acetic acid is 2.5%,l%,1.5%,respectively.the optimum reaction condition of chitosan degradation with hydrogen peroxideunder the catalysis of phosphotungstic acid was obtained as follows: hydrogen peroxide 2.7mol/L,the mass ratio of phosphotungstic acid to chitosan was 0.01, reaction time 20min, reaction temperature 90 °C. Water-soluble chitosan that average molecular weight is 12000 was produced under two optimum reaction condition by three experimentations.The organic-inorganic complexes of phosphotungstic acid with chitosan and chitosans degraded were synthesized. The complexes were characterized by Fourier transform infrared spectra analysis and diffuse reflectance spectra analysis, and their primary antibacterial activity was studied. The experimental results show that heteropolyanion and the amidocyanogen of chitosan and chitosans degraded come into being a stronger reciprocity, the heteropolyanion of complexes retains the configuration of Keggin. the complex of heteropolyanion and degraded chitosan have an excellent antibacterial activity to Escherichia coh\ microzyme> Aspergillus expect Staphylococcus aureus, the ntibacterial activity may be arose by the adsorption.