The Influence of Adsorbed Dyes on the Yield Stress of Nylon Filaments

Abstract

The effects of different dyes on the yield stress of nylon filaments have been studied, and inferences have then been made attributing the observed effects to the operations of different molecular forces in different instances ( e.g. ionic interactions, nonpolar van dcr Waal's forces, and hydrogen honds). Several acid and disperse azo dyes were selected together with those anthraquinone dyes with similar parent chemical structure. They were applied to drawn nylon monofilaments. The stress-strain curves of dyed and undyed filaments were measured, and their yield-strcss values were obtained. Acid dyes attached to amine ends or amide groups of nylon by ionic interactions made the yield-stress increase, whereas disperse dyes attached by hydrogen bonds, dispersion forces; and dipole-dipole forces had little effect on it. It should be noted that the resistance to bond-rotation of amide groups of nylon is stronger when acid dyes are adsorbed. In this work, acid azo dye had a little more effect than acid anthraquinone dye.