Cotton fabric with good antimicrobial activity and durability to washing is
obtained by using chito-oligosaccharides without the need for a binding ch
emical as a crosslinker. The fully deacetylated chitosan is depolymerized i
nto chito-oligosaccharide using sodium nitrite. The average degree of polym
erization (DP) of chito-oligosaccharide is determined by colorimetric titra
tion of a terminal aldehyde group of chito-oligosaccharide. In a pad-dry-cu
re process, two different chito-oligosaccharides (DP = 3 and 10) are applie
d to cotton fabric using the chemical reactivity of the terminal aldehyde g
roup. The antimicrobial activity and durability to washing of the treated c
otton an evaluated. The results show that at the fiftieth wash cycle, the c
otton fabrics treated with 2.4% chito-oligosaccharide are able to maintain
95% (for a DP of 3) and 100% (for a DP of 10) bacterial reductions.