One pot application of a green chemistry-based finish for cotton fabric, providing hydrophobic, flame retardant, and antimicrobial properties

Abstract

Fluorinated and formaldehyde-based compounds impart excellent hydrophobicity and flame-retardant properties to cotton fabrics. However, they come with various health and environmental risks. A novel hydrophobic, flame retardant, and antimicrobial finishing agent free from fluorine and formaldehyde was synthesized. The diammonium phosphate octadecyl citrate (DAPOC) was synthesized by using stearic acid (octadecanoic acid), citric acid (propane-1,2,3-tricarboxylic acid), and diammonium hydrogen phosphate. It was grafted onto the cotton fabrics by employing the conventional pad-dry-cure method. The results indicated that this newly developed finish could be chemically bonded to cotton fabrics through C–O–C covalent bonds. The contact angle of the cotton fabric finished with a 12% concentration of the finishing agent reached 151.9°. Additionally, the finished cotton fabrics displayed evident flame-retardant properties. After undergoing 20 laundering cycles, DAPOC maintained strong hydrophobic and flame-retardant characteristics, demonstrating its durability. The chemical structure of DAPOC was verified by nuclear magnetic resonance spectroscopy (¹H-NMR). The thermogravimetric analysis confirmed the flame-retardant nature of the treated cotton fabric samples. Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX), and Fourier-transform infrared spectroscopy (FTIR) results demonstrated the successful grafting of the newly created finish onto the cotton fiber. X-ray diffraction (XRD) spectra depicted that the crystalline structure of finished cotton fabric remained mostly unaltered. Furthermore, the finished cotton fabric exhibited commendable antimicrobial properties due to the inclusion of citric acid.