| Inorganic antibacterial agent consists of inorganic carrier and metal ion. It has many advantages such as long-acting antibacterial, non-talerance, strong heat resistance, etc, which make its application in the fields of plastics, chemical fiber, ceramic and so on attract tremendous attention. Ag/SiO2antibacterial agent has potential application in various fields for its advantages such as low price, high chemical durability and releasing silver ions for a long period of time. So it gets the favor of a lot of researchers. Ag+is one of the excellent candidates for preparing antibacterial agent for the lowest minimal inhibitory concentration and low toxicity towards mammalian cells. And Ag NPs has enhanced antibacterial performance due to the unique optical, electronic and catalytic properties of arising from the quantum size effect and large surface energy.Textile is essential for daily life, but easily contaminated by bacteria, which seriously affect its practicability. So the ordinary textiles endowed with antibacterial activity raised the added value of products and attached increasingly importance of worldwide researchers. Natural fibers tend to act as an excellent medium for the growth of microorganisms because of its abundant nutrient substance. Silk is the lightest, thinnest, softest natural fiber and has great air permeability and water vapor transmission, so it is widely used in costume, modern industry and medical science. Ramie cotton fabric brings the advantages of cotton fiber and hemp fiber together. It has firm texture, smooth feel, great air permeability and water vapor transmission, is very suitable for clothing and home textile fabrics. How to prepare antibacterial textile with long antibacterial activity is a key problem.In this work, a kind of light color Ag/SiO2antibacterial agent was obtained by air isolation method during chemical reduction. The effect of Ag+concentration and air isolation to the color was discussed. Grafted antibacterial silk and ramie cotton fabric were obtained by grafting Ag/SiO2antibacterial agent with coupling agent KH550and KH570, respectively. The morphology and composition were characterized by field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscope (HRTEM) and Fourier transform infrared spectroscopy (FTIR). The antibacterial performances were detected by inhibition zone method, minimal inhibitory concentration (MIC) method and oscillation flask method. The results show that:(1) Both reducing Ag+concentration and air isolation could be effective measures used to prepare light color Ag/SiO2antibacterial agent. With the Ag+concentration of3.54mM and air isolation during reaction and drying, Ag/SiO2 powder was almost white. The Ag at the reduction state was account for92%, and the Ag NPS were prepared with an average particle size of about30nm.(2) The antibacterial activity of Ag/SiO2antibacterial agent was improved with higher Ag+concentration, and air isolation treatment has no negative impact on antibacterial performance. Ag/SiO2antibacterial agent demonstrated a good antibacterial performance against E. coli, S. aureus and Tritirachium album. The MIC of Ag in Ag/SiO2powder was only94mg/L.(3) The antibacterial rates of G-silk against E. coli and S. aureus were both over90%, and still over80%even after washing for30times. And according to the FTIR transmittance spectra, the grafted antibacterial silk has chemical structure change.(4) The chemical structure of grafted antibacterial ramie cotton fabric was changed on the basis of FTIR spectra. The antibacterial rates against E. coli and S. aureus were92.5%and86.7%, respectively. |
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