Dye Molecules as Bridges for Functional Modifications of Nylon: Antimicrobial Functions

Abstract

Dye molecules often contain reactive groups such as sulfonate, amino, and hydroxyl that serve as auxochromes in dyes, but are chemically reactive and potentially useful as linkers for attaching functional moieties to synthetic fibers. Using these reactive groups as a means of functionalizing textile materials is proposed and implemented in this study of modifying chemically stable polymers. As an example of this innovative finishing tech nology, acid dyed nylon 66 and nylon 6 fabrics are finished in a quaternary ammonium salt solution, and durable and refreshable antimicrobial functions are conferred on the fibers. Most acid dyes can be used with this method to incorporate quaternary ammonium salts into nylon fabrics. The add-on levels of the salts on the dyed and undyed fabrics are significantly different, evidence for the occurrence of interactions of dye molecules with salts. Quantitative antimicrobial evaluations of the treated fabrics reveal that there are significant reductions in bacterial populations up on surface contact with the finished fabrics. The bactericidal function of the fabrics survives through ten Launder-Ometer washes, according to AATCC test method 61-1994, equivalent to fifty machine washes.