Functional Modification Of Silk Fabric By Cactus/Silver Nanoparticles

Silk, a most important natural textile, is loved by people for its excellent properties, such as softness and elegant. Because silk fiber is very thin and the chemical composite contain a large number of amino acids, hydrophilic groups and photosensitive disulfide, silk fabric is susceptible to micro-organisms, such as bacteria and fungi. They can influence the health of people. Silk fabric is easy to fading and yellowing in the sun. In order to show the excellent performance and overcome wearability defects of silk fiber, people pay more attention for modification and practice for a long time.The research of silver as an antimicrobial is honored by the time, with the people pay more attention to environmental protection and green chemisty, using plant leaf to reduction silver nanoparticles become a hot research. There are many ways to making silver nanoparticles, the method of use plant extracts to prepared silver nanoparticles is relatively simple. This way is suitable for large-scale preparation of nanoparticle, but use cactus extracts as reducing and stabilizing agents to reducing silver ions to silver nanoparticles have not been reported. In this study, we use cactus extracts and silver nanoparticles that reduced by sliver ion to treated silk fabric, the silk fabric obtained excellent ultraviolet resistance, anti-bacterial properties and washing performance. We also use steamed method to reducing sliver nanoparticles on the surface of silk fabric directly. The fabric obtained excellent antibacterial properties, solve the problem such as instability and easy to reunion in the solution.Use chemical method to extract effective substance from cactus, analyzed and characterized the structure of the extract. Treated silk fabric with the extract, discussed the effects of UV-vis for the various factors in the extract process; tested the structure and properties of silk fabric.Use cactus extracts to prepared silver nanoparticles solution, use DLS、TEM、UV-vis to characterized the silver nanoparticles solution that synthesized by the silver ammonia and cactus extract. The test showed the UV absorption peak at 420nm. We also test the stability of the silver nanoparticle in the solution.Use silver nanoparticle solution to treated silk fibers, SEM and EDS test shows the surface of silk fabric distributed silver nanoparticles. Other tests found there is not obvious change with random conformation of silk fabric, the crystallinity is also not change, the essential thermodynamic properties is the same with common silk, and there is a little effect of mechanical properties.Use silver nanoparticle solution to treated silk fabric, obtained the optimum treatment process by single factor experiment. The finished silk fabric have good antibacterial properties, the treated silk fabrics showed 99.93% of bacterial reduction to S. aureus and 99.88% bacterial reduction to E. coli, respectively. The antimictobial activities of the treated silk fabric were maintained over at 98% reduction level even after being exposed 50 consecutive home laundering conditions.According to the principle of the in-situ mechanism, we can product silver nanoparticles on the surface of silk fabric. The method can distribute the silver nanoparticles uniformly on the surface of silk fabric, it can avoid reunited of the silver nanoparticles. The absorption peak at 400-420nm with the steamed fabric is the same with the silver nanoparticles solution. The antibacterial tests showed the modified silk fabrics have good antibacterial activity and antibacterial washing resistance. The steaming silk fabric has a large number of silver nanoparticls, the structural has a little change through the finishing process, and there is small effect on the mechanical properties and use performance.All these studies indicated that the cactus extracts can applied to functional modification of silk. And these studies may widen the application fields of the bioreduction silver nanoparticles technology and provide a new idea for functional modification of other fibers or fabrics.