The Application And Preparation Of Chitosan And Nano-inorganics Composites

Chitosan (CS), a high molecular weight cationic polysaccharide, has attracted considerable interest because of its distinguished properties of non-toxicity, good mechanical property, antibacterial activity, biocompatibility and excellent film-forming ability and been applied in biomaterial, medicinal, environmental and other industrial fields. However, the antibacterial properties of chitosan were affected by many factors, such as the degree of deacetylation, the molecular weight, pH, the concentration and so on. And in practice, chitosan as antibacterial material was not ideal. Nano-inorganics, such as zinc oxide and silver has attracted much attention for their unique properties of air purification, sterilization and antibacteria. Therefore, chitosan composites that nano-inorganics are doped in the chitosan to improve the antibacterial properties have been a new hot spot.Novel chitosan/ZnO nanoparticles (CS/nano-ZnO) and chitosan/Ag/ZnO (CS/Ag/ZnO) composite membranes were prepared via a new method of sol-cast transformation. The products were studied by UV-vis absorption spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy Dispersive X-Ray Fluorescence Spectrometry (EDX) and thermogravimetry (TG). The alkaline concentration, the temperature of immersion, the time of immersion affected the preparation of CS/nano-ZnO composite membranes and the optimum conditions were ascertained. The water swelling ratios, mechanical properties and antibacterial activities against B. subtilis, E. coli, S. aureus, Penicillium, Aspergillus, Rhizopus and yeast of the composite membranes were researched.The antibacterial mechanisms of CS/nano-ZnO and CS/Ag/ZnO composite membranes were researched. And it would provide theoretical basis on the application of these antibacterial composite.The new route of sol-cast transformation would provide a new way to synthesize chitosan/nano-inorganics composites.