Coloration of polyamide fibers in an aqueous solution by Maillard reaction

Polyamide fibers, such as wool, silk, and nylon fibers, could be colored in an aqueous solution containing reducing sugars, similar to the coloration of various foods containing both protein and reducing sugars, by the Maillard reaction. For example, the color of the wool fibers reacted with xylose, one of the reducing sugars, was changed in succession from beige to yellow to orange with the reaction time. Further examination of the reaction conditions, such as reaction time, reaction temperature, types of reducing sugar and their concentration, enabled deep coloration, such as brown. Furthermore, the properties of the colored fibers, such as mechanical strength and hygroscopicity, were also investigated here.