Development and optimisation of green flame retardant properties of cotton fabric treated with chitosan nanoparticles and phosphate using Taguchi method

The inherent flammability of cotton poses a significant fire risk during combustion. In this work, an eco-friendly and sustainable flame-retardant (FR) cotton woven fabric was fabricated using bio-based chitosan nanoparticles (ChNPs) and diammonium phosphate (DAP). The Taguchi method was employed to optimise the FR treatment process, utilising an L9 orthogonal array design comprising nine experiments with three replications each. Chemical characterization of the treated fabrics was performed using Fourier Transform Infrared Spectroscopy (FTIR). The successful attachment of ChNPs and DAP to the cotton fabric surface was confirmed through Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDX). The size and morphology of ChNPs were analysed using Transmission Electron Microscopy (TEM). Thermogravimetric Analysis (TGA) was conducted to assess the thermal stability and percentage of weight loss in the fabric samples. The treated fabrics were further evaluated for flame spread time and tensile strength. The study successfully identified the optimal treatment conditions as a DAP concentration of 6%, a ChNP concentration of 5 g/L, and a curing temperature of 160 °C. The results showed that flame retardancy improved significantly with increasing DAP concentration and curing temperature, while ChNPs contributed moderately to the FR performance. TGA indicated that untreated cotton completely degraded around 510 °C, whereas treated samples remained thermally stable up to 700 °C, with a residue of 34%. In conclusion, the application of the Taguchi method proved to be an effective approach for optimising flame-retardant treatment parameters, enhancing the thermal and fire-resistant properties of cotton fabric in an eco-friendly and sustainable manner.