| Nano-silver antimicrobial fibers are emerging antimicrobial textiles. It can protect the skin, eliminate the offensive smell, and prevent the spread of disease, which has the function of cleaning and hygiene. Meanwhile, it can prevent fiber products from microbial damage. It can be used in daily necessities, including uniforms, clothes, shirts, underwear, pajamas, bedding and a handkerchief and so on. Thus, it has a very broad market prospects. Considering the above reasons, our research focused on preparation of Ag colloidal dispersions and preparation of durable and permanent antibacterial cotton products using a new finishing process, inserting nanometer-like silver particles to cotton fibers and the thesis consists of the following contents:1. TiO2/Ag colloidal dispersions was prepared by using PEG as template.1) TiO2 and Ag nanoparticles are both spherical, the average particle size of TiO2 among these nanomaterials was around 50 nm, and the average particle size of nano-silver was around 20 nm. X-ray diffraction (XRD) reveals that the formation of metallic silver particles crystallized in the face centered cubic (fcc) structure and the TiO2 samples exhibit well-crystallized anatase phase.2) TiO2/Ag has excellent anti-UV effect, complex colloidal solution has smallest UV protective effect with concentration at 0.29 mg/mL, folly protective ultraviolet radiation effect as the concentration is 1.19 mg/mL.3) TiO2/Ag has strong antibacterial effect. The growth inhibition rates of 10 ppm TiO2/Ag against Escherichia coli and Staphylococcus aureus are 99.9% and 97.9% respectively.2. Nano-Ag colloidal dispersions were prepared by using PEG as template. The effect of reaction temperature and ratio of AgNO3 to ascorbic acid on conversion rate of silver ion were determined by Volhard law.1) Transmission electron microscopy (TEM) analysis showed that stable spherical metal particles 3-50 nm in diameter with a well-crystallized structure were obtained by using tannic acid as co-reducing agent, and particles 10-20 nm in diameter were gained by using ascorbic acid as co-reducing agent.2) Conversion rate of silver ion can exceed 94.1% under the following condition:temperature was fixed at 60℃, concentration of AgNO3 is 20 mg/mL, the initial ratio between AgNO3 and ascorbic acid is 4:1.25. However, the Ag colloidal solution would become unstable with the increase of ascorbic acid.3) MIC against E.coli of Ag-nanoparticles reduced by ascorbic acid and tannic acid are 5 ppm, comparing to 16 ppm against Streptomyces. All of them were significantly lower than the values obtained for the Ag metal particles.3. The bacterial inactivation of E.coli and S. aureus on Ag-cotton textiles were investigated under different experimental conditions with novel stable Ag colloids fixed on cotton textiles. X-ray photoelectron spectroscopy (XPS) results indicated that only one states of silver were present on the surface of the antimicrobial textile. The antimicrobial test results showed that the treated textile has an excellent antimicrobial effect and laundering durability. Bacterial inhibition ring of antimicrobial textile reached 6 mm, which was treated by 100 ppm nano-silver at bath ratio of 1:50 for 1 min,10 mm(treated by 250 ppm nano-silver at bath ratio of 1:50 for 30 min).The bacterial inhibition ring of antimicrobial cotton finished by 100 ppm nano-Ag for 1 min against E. coli and S. aureus are more than 1 mm as the antibacterial fabric was washed for 50 times. Growth inhibition rates against S. aureus is higher than 80%, and E. coli higher than 70%. Thus, antibacterial finished products can reach AAA result.4. Silver nano-particles coated by poly (hydroxyethyl methacrylate) using N, N-dimethylformamide (DMF) as a medium has been performed successfully using solution polymerization method. Transmission electron microscopy(TEM) analysis showed that stable Ag spherical metal particles, coated by PHEMA,20 nm in diameter with a well-crystallized structure were obtained. Antimicrobial properties of Ag/PHEMA nano-composite was studied primarily. |
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