Salt free dyeing properties of cotton fabrics grafted with ε-polylysine(ε-PL)

Cotton fabric was chemically modified with ε-Poly-L-lysine (ε-PL), which contains abundant imino groups and primary amino groups. ε-PL was grafted onto cotton fabric by a reaction between aldehyde groups of oxidized cellulose and amino groups of ε-PL. FT-IR of grafted cotton fabrics was researched and it demonstrated the covalent bonds combination between ε-PL and cellulose fibers. Zeta potential of cotton fabrics grafted with ε-PL was positive when pH was lower than 7.5. Dyeing properties of modified cotton fabrics were investigated. Exhaustion rate and fixation rate of reactive dyes on modified cotton fabrics with a salt-free dyeing process were higher than those of unmodified cotton fabrics with a conventional dyeing process. Compared with that of the unmodified cotton fabrics, the washing fastness, rubbing fastness, and leveling properties of the modified cotton fabrics were also good. The dyeing behavior of Procion Red H-E3B on modified cotton fabric was examined and found to follow a Langmuir-type adsorption curve. It is concluded that ε-PL could be used as a salt-free auxiliary in reactive dyeing on cotton fabrics.