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100B Preparation and antibacterial activity of silver-loaded chitosan grafted vanillin latex
This paper was completed by a research scholar at the College of Science, Hebei University of Science and Technology. The paper discusses the preparation and antibacterial properties of silver-loaded chitosan-grafted vanillin latex, which was published in the important journal
In order to enhance the antibacterial activity of chitosan and expand its application field, nano-silver particles were introduced into the matrix and graft modified. Grafting vanillin with chitosan by microwave irradiation, and then reducing silver nitrate with vanillin to obtain nano silver particles uniformly dispersed in chitosan vanillin graft (CS-g-VA) latex, ie Ag /CS-g-VA compound latex. The influencing factors of the preparation of Ag/CS-g-VA composite latex were discussed. The structure and thermal properties were characterized by SEM, TEM, FTIR, XRD, UV-vis and TG-DSC. The results show that the ideal conditions for synthesizing Ag/CS-g-VA are: vanillin mass fraction is 6.0%, CS-g-VA mass fraction is 4.0%, and silver nitrate concentration is 0.20 mol/L. . The inhibitory effect of Ag/CS-g-VA on Escherichia coli and Bacillus subtilis was studied by antibacterial test. The results show that the Ag/CS-g-VA compound latex has more effective antibacterial properties than the single chitosan antibacterial agent.
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The grafting reaction of vanillin with chitosan was carried out by microwave irradiation to obtain grafted polymer CS-g-VA, and then CS-g-VA was combined with AgNO3 by sol-gel method to obtain Ag/CS-g. -VA compound latex. The ideal conditions for preparing Ag/CS-g-VA are: CS-g-VA mass fraction is 4.0%, AgNO3 solution concentration is 0.20 mol/L, and vanillin mass fraction is 6.0%. The TEM image shows that the nano-silver is uniformly dispersed on the surface of Ag/CS-g-VA sol, and there is no obvious agglomeration. The particle size of Ag particles is 10-20 nm. The XRD results show that chitosan is amorphous and is encapsulated. The buried nano-silver crystal form is face-centered cubic; the infrared spectrum shows that the amino group of chitosan reacts with vanillin; the TG-DTA analysis shows that the graft is combined with nano-silver to make the thermal properties of the polymer more stable. . Antibacterial experiments showed that the antibacterial effect of Ag/CS-g-VA on Escherichia coli and Bacillus subtilis under ultraviolet light was better than that under visible light.
3.0 g of chitosan was weighed into a 250 mL four-necked flask, and then poured into 60 mL of isopropanol for 1 hour. 4.4 g of vanillin was dissolved in a mixed solvent of 120 mL of isopropanol and ethanol (V (isopropanol): V (ethanol) = 1:1), and then placed in a chitosan soaking solution, and stirred. The chitosan and vanillin were uniformly dispersed, and a water bath protection device was placed in a four-necked flask, and placed in a microwave oven (XH100B, supplied by Beijing Xiangyu Technology Development Co., Ltd.), and reacted at 300 W at 70 ° C for 12 min. After cooling, suction filtration, soaking the filter residue with 1 mol/L NaOH solution for 5-8 h, then filtering, washing with deionized water and acetone, and drying to obtain a yellow powdery product. The synthetic route of preparing CS-g-VA graft by microwave irradiation is shown in Fig. 1.