Flammability and combustion behavior of cotton fabrics treated by the sol gel method using ionic liquids combined with different anions

An ionic liquid (IL)-assisted cotton fabric treatment was developed that uses the sol–gel method, methylimidazolium and pyridinium cations combined with Cl⁻, PF₆⁻, (CF₃SO₂)₂N⁻, BF₄⁻ and CH₃CO₂⁻ anions. Scanning electron microscopy, elemental analysis and Fourier transform infrared spectroscopy were first performed to characterize the morphology and the chemical composition of the treated and untreated cotton fabrics. Furthermore, the effect of IL-based treatment on the tensile strength of cotton fabrics was evaluated using a uniaxial tensile test. The thermal behavior of cotton fabrics was investigated by thermogravimetric analysis, microscale combustion calorimetry, limiting oxygen index (LOI) and vertical burning test. It was found that the as produced IL-treated cotton fabrics exhibited a good thermal stability and showed good flame retardant properties. The best result was found for fabrics treated by IL combined with PF₆⁻ anion, in which the total heat release value was reduced from 11.47 kJ/g for untreated fabrics to 6.32 kJ/g for treated fabrics. The result from LOI test indicated that the treated cotton fabrics exhibited a better LOI value of 25% compared to the untreated fabrics (LOI = 20%), indicating that IL-based treatment has contributed to the protection of cotton fabrics from degradation. Herein, we demonstrate that IL-assisted sol–gel method could be used as an effective approach to develop cotton fabrics with improved characteristics for textile application.