A Study on Flame Retardant efficacy of Eggshell Biowaste on Cotton Fabric

Abstract

Cotton textiles possess desirable properties, including high hygroscopicity, air permeability, and biodegradability. However, their high cellulose content makes them highly flammable, limiting their use in several sectors. This study therefore evaluated an eggshell-biowaste treatment for imparting flame retardancy to cotton fabric. Before treatment, the selected cotton fabric was enzymatically desized and scoured using amylase and pectinase, respectively, to improve wettability. The eggshell finish was applied by the exhaust method using 25% eggshell powder, 4% chitosan binder, a material-to-liquor ratio of 1:40, pH 6.5, and a treatment temperature of 80 °C for 45 min. The fabric was dried at 100 °C for 13 min and cured at 140 °C for 4 min. The treated fabric was characterised using field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). FE-SEM and FTIR confirmed the deposition of eggshell particles on the fabric surface, including characteristic peaks and distinctive flower-like clusters. TGA indicated slower degradation and greater residual mass in the treated fabric than in the untreated fabric. The limiting oxygen index increased from 18% to 26%. Horizontal, vertical, and inclined flammability testing further showed reductions in burning rate, burning time, and char length after treatment. These findings indicate that eggshell biowaste, used with chitosan and sodium hypophosphite, has potential as a bio-based treatment for improving the flame-retardant behaviour of cotton fabric. Further evaluation of laundering durability and end-use performance is required.