Dyeing Improvement and Stability of Antibacterial Properties in Chitosan-Modified Cotton and Polyamide 6,6 Fabrics

Cotton and polyamide 6,6 fabrics coated with chitosan, a natural biopolymer, have beentested against two different bacteria strains: Staphylococcus aureus as Gram-positive bacterium andEscherichia coli as Gram-negative bacterium. Using the ASTM standard method (Standard TestMethod for Determining the Antimicrobial Activity of Antimicrobial Agents Under Dynamic ContactConditions) for antibacterial testing, the treated fabrics is contacted for 1 h with the bacterial inoculum,the present study aims to investigate the possibility to reach interesting results considering shortercontact times. Moreover, the antibacterial activity of chitosan-treated fibers dyed with a natural dye,Carmine Red, was evaluated since chitosan has an interesting property that favors the attachment ofthe dye to the fiber (cross-linking ability). Finally, fabric samples were tested after washing cycles toverify the resistance of the dye and if the antibacterial property was maintained.