Soybean Oil and Nonthermal Plasma Pretreatment to Dye Para-Aramid Woven Fabrics with Disperse Dye Using a Glycerol-Based Dye Bath

High-performance para-aramid fibers offer a number of uses as strong, lightweight materials for protective vests, helmets, tires, and other applications. The chemically inert nature of the fibers makes them difficult to dye or durably print by conventional dyeing techniques for textiles, and solution dyeing during production of the fibers can limit the color of para-aramid fabrics to the color of the spun yarn prior to weaving or knitting and thereby limit the practical applications of these textiles as protective outerwear. This study presents a new method developed to improve the dyeing of woven para-aramid fabrics with a disperse dye. Specifically, sequential experimentation proves the beneficial effects of first soaking para-aramid fabrics in soybean oil followed by surface treatment with atmospheric nonthermal plasma and using glycerol as the dispersant and sodium chloride as an electrolyte without the addition of other auxiliary chemicals. Under the optimized treatment conditions of this study, the color strength (K/S value) of dyed para-aramid fabrics increased to 3.89 from 0.35 of the untreated samples as determined from spectral analysis of the sample reflectance in the visible range. Fourier transform infrared spectroscopy analysis revealed that the high content of unsaturated fatty acids in soybean oil and their interaction with reactive species in the ambient nonthermal plasma were the primary factors for improving the color strength of the dyed para-aramid fabrics.