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

Abstract

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.

Soybean Oil-Based Biopolymers Induced by Nonthermal Plasma to Enhance the Dyeing of Para-Aramids with a Cationic Dye

“…TWEEN was the only factor not involved in any significant interactions; the addition of the surfactant negatively affected dyeing performance, consistent with our previous observations [ 9 , 10 ]. The surfactant, although helping to form a dye dispersion, might also hinder the diffusion of the dye onto the para-aramid fiber fabrics.…”

“…The para-aramid fabrics used in this study are made of tightly woven 300 Denier continuous filament and were provided by the U.S. Army Development Command—Soldier Center (Natick, MA, USA). This highly crystalline material has been proven undyeable by conventional methods using either a cationic dye or a disperse dye, even with nonthermal plasma surface treatment, but were dyed using soybean oil/NTP pretreatments [ 9 , 10 ]. Blue cationic dye (Victoria Blue R, CAS Number 2185-86-6), Disperse Red 1 acrylate dye (CAS Number 13695-46-0), AESO (CAS Number 91722-14-4), acrylic acid (CAS Number 79-10-7), and ethyl acetate (CAS Number 141-78-6) were purchased from Sigma-Aldrich (St. Louis, MO, USA).…”

“…Our previous studies [ 9 , 10 ] demonstrated that pretreatment with soybean oil followed by nonthermal plasma (NTP) treatment enabled dyeing para-aramids to significantly high color strength without other chemical additives; and this new method is compatible with both a disperse dye and a basic dye, showing the potential of this method replacing the environmentally unfriendly chemicals in current dyeing practices with renewable, environmentally friendly materials to improve the dyeing of para-aramid fabrics. The proposed mechanism for improved dyeing is that the soybean oil diffuses onto woven fabric and adsorbs onto the surfaces of yarns and fibers, and the subsequent NTP treatment induces the formation of a polymerized network in situ, enabling dyeing to a higher color strength.…”

Dyeing Para-Aramid Textiles Pretreated with Soybean Oil and Nonthermal Plasma Using Cationic Dye

“…For the purposes of providing a visual demonstration comparing the dyeing strengths of different treatments, select samples were imaged using a flatbed scanner ( Figure 8 ). Compared with the previous investigation of dyeing para-aramids with this method and using a disperse dye [ 27 ], it is demonstrated that the pretreatment of soybean oil followed by NTP treatment method is compatible with dyeing with both disperse dye and cationic dye. Further, this method enables dyeing to a significantly high color strength, although the disperse dye requires glycerol as a dispersant, but water as the solvent is better suited for the use of cationic dye.…”

“…The SDBD system has been described previously for dyeing with a disperse dye [ 27 ] and is summarized here. The SDBD apparatus uses ambient air as the feed gas and comprises two electrodes that are separated by an alumina dielectric plate (dimensions = 108 × 95 × 1 mm 3 thick) and powered by a high voltage power source with a sinusoidal high voltage of 9.2 kV that was tuned to a 23.2 kHz resonance frequency (see Figure 1 ).…”