Application of Novel Triazolium-Containing Hydrogels to Cotton Fabrics: Evaluation of Their Flame Retardancy and Antibacterial Properties

A novel series of triazolium ionic salts were synthesized and characterized using Fourier transform infrared spectroscopy as well as ¹H and ¹³C nuclear magnetic resonance spectroscopy. The thermal degradation kinetics and activation energy of the ionic salts were studied using Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, and Starink methodologies. The results indicated that the thermal degradation mechanism of the synthesized triazolium flame retardants is influenced by the mono- and dicationic triazolium rings with different alkyl chain lengths. The activation energy increased with the decrease in the alkyl chain length and the addition of a triazolium ring. Triazolium-containing hydrogels were prepared and applied to cotton fabrics to enhance their flame-retardant and antibacterial properties. The vertical flammability test results confirmed that PBDIL12_20, which contained 20 wt % dicationic ionic salt, exhibited the highest flame retardancy among the tested samples. All the cotton fabrics treated with the triazolium hydrogels exhibited excellent antibacterial activity against Staphylococcus aureus and <i>Escherichia coli</i>, achieving bacteriostatic rates of >99%. This study presents a novel method for the development of flame-retardant and antibacterial cotton fabrics, which can be used in protective clothing to safeguard skin from fire and health hazards. The triazolium salts on normal cells (the human keratinocyte cell line (HaCaT) and the human dermal fibroblast cell line (BJ)) were used for MTT viability analysis.