Two birds, one stone: Enhancement of flame retardancy and antibacterial property of viscose fabric using an aminoazole-based cyclotriphosphazene

Enhancing the fire-retardant and antibacterial properties of viscose fabric through a simple strategy is crucial and urgent. In this study, an aminoazole-based cyclotriphosphazene (HATA) was designed and synthesized through nucleophilic substitution between hexachlorocyclotriphosphazene and 3-amino-1,2,4-triazole. The application of a rapid dipping strategy and the use of 10 wt% HATA aqueous solution significantly increased the limiting oxygen index of the viscose fabric from 19.3 % to 28.4 %. In addition, the HATA-treated fabric exhibited self-extinguishing properties in vertical flame testing. The peak heat release rate of HATA-treated fabric, according to pyrolysis combustion flow calorimetry, significantly decreased by over 83 %. The scanning electron microscope images revealed the original woven fabric structure after burning. The thermogravimetric infrared spectroscopy and X-ray photoelectron spectroscopy results confirmed that the introduction HATA in viscose hindered the release of combustible gas and facilitated the formation of a protective char layer. In addition, 10 % HATA-viscose exhibited remarkable antimicrobial properties, achieving 99.96 % and 99.84 % antibacterial rates against Staphylococcus aureus and Escherichia coli, respectively. Furthermore, HATA-treated viscose fabric exhibited favorable mechanical performance, whiteness, and air permeability. This research provides a simple and effective flame-retardant and antibacterial treatment strategy for viscose fabric.