Studies On Chitosan's Antibacterial Property Of Worsted Fabric

Wool fabrics are founded for its excellent wearing properties, meanwhile it also has the disadvantage of poor resistance to bacterial. In this paper, we use friendly environmental substance-- chitosan and citric acid to impart the properties of anti-bacterial to wool fabric through pad-dry-cure treatment.Through discussing domestic and foreign antibacterial testing methods, problems of the domestic antibacterial testing methods were put forward. On the basis of lots of antibacterial testing, the problems of inproved AATCC100 and Quinn methods were analyzed, and the Shake Flask standard was determined for wool fabric testing.After testing the finished worsted fabric, effects of molecular weight, degree of deacetylation and concentration of chitosan on antibacterial properties were analyzed in this study. Results shows that the antibacterial properties are improved as increase of concentration and degree of deacetylation, and the antibacterial properties are improved as the decrease of molecular weight. The antibacterial rate of Staphylococcus aureus and Escherichia coli both exceeds 95%, when worsted fabric was finished by chitosan with molecular weight of 496000 under concentration of 0.25%. The antibacterial rate also exceeds 65%, when after 20 times washing, so the worsted fabric has good washing endurance.Analyzing the factors in the treatment process: citric acid concentration, chitosan concentration, catalyst concentration, curing temperature and time. Considering the finishing ways and effect, the optimized treatment condition: citric acid concentration is 0.8%, chitosan concentration is 0.25%, catalyst concentration is 1%, softener ACN concentration is 1.8%, MEJ concentration is 0.7%. Treatment technics: procuring temperature and time is 80℃×5min, curing temperature and time is 120℃×120s.The crease-resistance and handle of treated fabric is improved, but the breaking strength and draping properties decreased slightly. The surface roughness of finished worsted fabric is decreased and moisture absorbent property and air permeability are also remained.SEM was employed to observe the surfaces of wool fabric before and after chitosan finishment. It was found that surface morphology of wool fabric was changed after chitosan finishment. Squama of wool fibers was filled with chitosan finishing agent. Nicolet Nexus FT-IR spectra curves showed that crosslinking ester linkages were formed in wool fabric and chitosan angent. Chitosan was combined with wool fibers through chemical bond under the bridge of citric acid, in which impart durable anti-bacterial.