Polydopamine/Reactive Red 239-Dyed Cotton Fibers with Hot Pad-Batch Dyeing for Enhancing Colorfastness

Abstract

Dopamine (DA) can undergo complex oxidative self-polymerization to modify the surface properties of cotton fabrics; however, the disordered polymerization of dopamine to polydopamine (PDA) results in poor colorfastness and limits the application of DA to textile fibers. To ensure the ordered polymerization of DA and the growth of PDA and to obtain good colorfastness and depth in the PDA-modified cotton, we used the hot pad-batch (HPB) dyeing method for DA and Reactive Red 239 (RR-239), along with the action of the fabrics squeezing each other. We compared the differences in colorfastness caused by the disordered and ordered polymerization of DA and aluminum ions. We studied the effect of sodium carbonate, DA, and RR-239 concentration on the K/S values of the cotton fabric. We also analyzed the dyeing mechanism of PDA/RR-239 for cotton fibers and the effect of the aluminum ions therein via attenuated total reflection–Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) and determined the UV resistance, mechanical properties, and thermal properties of the cotton fabric. HPB dyeing produced better colorfastness than exhaustive dyeing with a co-bath of DA/RR-239 and enabled ordered polymerization of PDA on the fibers. HPB dyeing accelerated the formation of PDA in the presence of a small amount of aluminum salt. Thus, HPB dyeing is suitable for the modification of cotton fabric with DA and reactive dyes because it is a short dyeing process that can improve the washing and rubbing colorfastness to 4 and 3–4, respectively.