Preparation Of Nanometer Composite Sol Containing AgCl And TiO₂ And Its Application To Cotton Fabrics

The inorganic antibiotic nano-material with silver as a new type of antibacterial material characterizes itself in being broader for spectrum, longer for durability and higher for safety than the organic antibacterial materials. Such inorganic material has broader market prospects along with the increasing demand for the quality of environment. So the study on the composite sol containing silver and titanium dioxide will be of great important both in science and application fields.In this article, the development, categories and properties of inorganic antibacterial agents were studied. The structure and characteristics of nano-materials, photochemical catalysis of nano-sized titanium dioxide were discussed in detail. And the antibacterial principles of the silver and titanium dioxide were analyzed. A new method of preparation of nanometer composite sol containing AgCl and TiO₂ was advanced, and its application to the fabrics was studied. Still further, the research work was described in detail as the following aspects.1) the preparation of nano-sized composite sol In the experiments, the homogeneous nano-sized composite sol was prepared by settling method with silver nitrate and nano-sized titanium dioxide. The effects of some factors on the stabilization and particle size of the sol were studied, such as pH, the concentration of each component, temperature and surface agents, etc. The particle Size was tested by Nano-size and Zeta-potentiometer Analyzer and TEM.The results showed that the optimum pH was 6.5 and the PVP had better performance than other surface agents. The average size of colloidal particles was rising and the distribution became asymmetry along with the increasing concentration of TiO₂. When the temperature rose, the particles reunited soon and the color changed more quickly. When PVP concentration was 1.5g/L, NaCl concentration was 1g/L and TiO₂ concentration was 3%, TEM illustrated that the diameter of the particles was between 20nm and 50nm with better distribution (Particle Distribution Index＜0.3) in room temperature.2) the application of the nano-sized composite sol to cotton fabricsThe second part mainly focused on the application of the composite sol on antibacterial finishing of cotton fabrics. The treatment process, antibacterial performance and washing durability of the treated fabrics were studied. Effects of the concentration of AgNO₃ and TiO₂ on the properties of the treated fabrics were discussed. The optimum treatment process has been discovered: padding for two times (pick-up 60～70%)→ high temperature steaming (95℃, 5min, the relative moisture was 90%)→washing→drying. The surface of the fiber was observed by SEM after antibacterial finishing.While increasing the concentration of the AgNO₃, the whiteness of the treated cotton fabrics was reduced, but the antibacterial performance was strengthened. When the concentration of AgNO₃ was 0.5mg/mL, the antibacterial efficacy to colibacillus could be more than 99%. After washing for 30 times, the antibacterial efficacy was still 90%. The anti-uv performance of the treated cotton fabrics was close related to the concentration of TiO₂. XRD illustrated that Ag immobilized on fabric existed in two forms, i. e. Ag and Ag⁺. The contents of Ag and TiO₂ in treated fabric were more than 300mg/kg, by atomic spectrum analyzer. In this experiment, the color of the Ag has little changes when the composite sol was used to finish cotton fabrics.