Preparation Of Colorless Polyethyleneimine-Silver Nanoparticles Antibacterial Agent And Application In Cotton-ramie Fabrics

Various microorganism mainly involving bacteria, fungus exist in our daily life and can cause skin infection to seriously effect on people’s health. Textiles is the first barrier which can reduce bacteria infections, and making the textiles have antibacterial can better resist bactria. Therefore, study on textiles with antibacterial already has been given more and more attentions, and add silver antibacterial agent to textile products was the main method to get antibacterial fabric. Nano silver agent was often used in antimicrobial products because of excellent antibacterial property. However, nano silver has some disadvantages including instability in air, being easily oxidizd, discoloration and so on. Especially for light color fabric, it could cause badly discolored and bring fatal effect. Therefore, research on colorless transparent nano silver agent with stable performance has important economic and practical significance. Branch Polyethyleneimine(BPEI), a cationic macromolecular polymer with a weak antibacterial property, could act as ligand to connect with silver ion because amount of amino group at its end. But in the presence of other reductant, it could act as the suitable stabilizer in synthesis of nano-silver. In this research, BPEI would be chosed to be stabilizer for the synthesis of nano-silver antibacterial agent. The thesis is composed by the following parts:1. The compound silver antibacterial agent was synthesized by chemical reduction reaction between the Ag NO3 and BPEI in aqueous solution. The products were characterized by UV-vis and TEM. The results showed that a transparent and stable compound silver antibacterial agent could be synthesized when the ratio of BPEI(Mw is about 10000) between silver ion was 0.4:1 for 3 h at 25°C. The antibacterial property against E. coli and S. aureus also had been detected. The results showed that the antibacterial disc with 12 mm which soaked in compound silver solution with concentration of 250 μg/m L have a large inhibition ring which the diameter on E. coli and S.aureus was 2 mm, 5 mm respectively. The whiteness of cloth sprayed by the compound silver antibacterial solution was detected. The results showed that the color of cloths had not changed much after the compound silver antibacterial solution was sprayed. But the whiteness of cloths would change with the increase of the content of silver iron and the posing time from decreasing slowly to finally stable. The compound silver antibacterial could be suitable for the application of light color fabric. The washability of cloth sprayed by the compound silver antibacterial solution was detected. The result showed that the inhibitory rate of the cloth to S.aureus was about 80 % after washing 10 times(based on the standard FZ/T 73023—2006), and it could not meet the antibacterial requirement of the cloth with antibacteiral which was A grade based on the standard FZ/T 73023—2006.2. Nano silver antibacterial agent was prepared by reaction between Na BH4 and Ag NO3 with the presence of BPEI(Mw is 10000). The conditions including the mole ratio of BPEI between Ag+ and Na BH4 to Ag+, reaction temperature, and reaction time were optimized. The products were characterized by the UV-vis and transmission electron microscopy(TEM), and inhibition ring test. A perfect nano silver antibacterial agent with a transparent and stable properties was obtained at the optimum condition, 2:1 of molar ratio of BPEI to Ag+, 1:1 of molar ratio of Na BH4 to Ag+, 45°C of reaction temperature, and 3 hours of reaction time. The results from TEM analyses showed that the products had a core-shell structure. The antibacterial disc with 12 mm which soaked in silver ion solution with concentration of 175 μg/m L had a large inhibition ring which the diameter on E. coli and S.aureus was 2 mm, 4.5 mm respectively.Compared with compound sliver antibacterial the antibacterial property of nano silver antibacterial agent was better. The whiteness of cloth sprayed by the nano silver antibacterial solution with concentration of 175 μg/m L was 85 after 2 months, which showed that the products had a ability against discoloration. The washability of cloth sprayed by the nano silver antibacterial solution was detected. The result showed that the inhibitory rate of the cloth with antibacterial to S.aureus was about 99 % after washing 10 times(based on the standard FZ/T 73023—2006), and it could meet the antibacterial requirement of the cloth with antibacteiral which was A grade based on the standard FZ/T 73023—2006.3. A new nano silver antibacterial agent with cool and refreshing function was prepared by using WS-3 as freshener. The results showed that an obvious cool and refreshing effect could be obtained when the concentration of WS-3 was 200 μg/m L. 1 K reduction in temperature could be achieved from this functional nano silver antibacterial agent. The WS-3 could be completely dissolved at the condition of 1:15 of volume ratio of ethanol and nano silver antibacterial agent. The antibacterial test showed that the antibacterial disc with 12 mm which soaked in silver ion solution with 175 μg/m L of concentration had a large inhibition zone which the diameter on E. coli and S.aureus was 4.5 mm, 6.5 mm respectively. The antibacterial properties of nano silver antibacterial agent with cool and refreshing function was excellent.