Synthesis Of Chitosan Stablized Nanosilyer Solution And Its Application On Cotton Fabrics

Antibacterial fabrics can not only help to keep our body healthy and prevent the spread of contagion, but also protect the fabrics from bacterial corrosion and improve the fabric properties. Silver nanoparticales (AgNPs) has been known as a kind of antiseptics with strong inhibitory and antibacterial efficiency as well as a board spectrum of antibacterial activitiy. However, the instability of AgNPs limited its application as an antibacterial agent. Chitosan (CS) has lots of active groups like hydroxyl and amino on its chain. So it can be used as a stabilizing agent. The aim of this study was to synthesize chitosan-based nanosilver (CS-AgNPs) solutions with good antibacterial activity and stability in order to put into the application of cotton fabric finishing.CS-AgNPs solutions were synthesized by chemical reduction method with chitosan as the stabilizing agent and sodium borohyride as the reducing agent. The influence of the concentration of silver nitrate, acetic acid and chitosan on the productivity and size of the nanosilver were studied. By controlling the concentration of silver nitrate less than3x10-4mol/L, the percentage of acetic acid between0.05%and0.7%, the content of chitosan between0.5%and0.7%and the molecular weight of chitosan about150,000, a relatively high productivity of AgNPs with small particle sizes and good stability was obtained. The obtained CS-AgNPs solution showed good antibacterial efficiency, and had a better effect on S. aureus than E. coil.Cotton fabrics were also treated with CS-AgNPs solutions. All of these fabrics exhibited superior antibacterial activity compared with the fabrics treated by chitosan solution and quaternized chitosan solution. The CS-AgNPs treated fabrics could kill3×105cfu/mL E. coil within120min, and showed good antibacterial activity even after81times home laundry. The reason for their good antibacterial property was that AgNPs which were fixed on fabrics by chitosan were slowly releasing Ag+which could interact with sulfur-containing proteins on the cell membrane and DNA. As a result, not only cell-wall permeability and respiration, but also DNA replication and enzyme functions were disturbed.The mechanical property, hydroscopicity, chromatic aberration and whiteness of the fabrics treated by CS-AgNPs were also studied. With chitosan concentration increasing, the treated fabrics showed better mechanical property, got lower hydroscopicity and had less color change.