Evaluation of flame retardant knitted fabrics treated with nitrogen containing natural substances using Taguchi method

Nitrogen containing flame retardants are the most commonly used flame retardants for textile materials. In the case of eco-friendly flame retardant textiles, it is better to utilize nitrogen-based natural flame retardants. In this study, aloe vera, bean seed, and tea leaf solutions were coated on 100% cotton, 100% viscose, and 100% para-aramid knitted fabric as nitrogen-based natural flame retardants. The limiting oxygen index (LOI) values of the treated fabrics increased notably, from 18 for untreated cotton to a maximum of 26.3 for cotton treated with aloe vera, from 18 for untreated viscose to 24.5 for viscose treated with tea leaf extract, and from 28 for untreated para-aramid to 39.2 for para-aramid treated with aloe vera. These results clearly indicate a significant enhancement in the flame retardant properties of the fabrics following treatment. The treated fabrics retained flame retardant properties (LOI > 21) even after five washes, though performance declined with repeated laundering. 45° flammability tests also showed a significant reduction in burning rates, confirming the effectiveness of the treatments. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric (TG) analysis, and scanning electron microscopy (SEM) were used to examine the surface chemistry of the treated fabric. X-ray diffraction showed that, in comparison to the untreated sample, the crystalline particles of the treated fabrics were marginally altered. SEM analysis demonstrated that the surface of the treated fibers was rather rough because of the tiny quantity of natural retardant that was covered, while FT-IR spectroscopy data showed that natural fire retardant components were grafted on the treated cotton, viscose, and para-aramid fibers. Finally, the Taguchi method was utilized to compare the flame retardancy effect of the treated fabrics considering their important resultant parameters. Overall, by improving the flame-resistant qualities of textiles, the nitrogen-based natural flame retardant could get around the drawbacks of sustainable flame retardants and make them appropriate for usage as nitrogen-based fire resistance textiles.