Preparation and properties of flame-retardant, antibacterial and hydrophobic cotton fabrics based on poly(dimethylsiloxane)-etherimide/ammonium phytate

[Objective] Cotton fabrics, widely favored for their excellent breathability and comfort, are extensively utilized in apparel and home textiles due to their softness and wearing comfort.However, reports indicate that fires cause substantial human casualties and financial losses annually.The inherent flammability of cotton fabrics, characterized by a limiting oxygen index(LOI)of only 18%, coupled with their susceptibility to bacterial growth, significantly restricts their application scope.In response to the growing demand for multifunctional textiles, developing cotton fabrics with flame-retardant, antibacterial, and hydrophobic properties has become essential to meet market requirements.[Methods] Poly(dimethylsiloxane)-etherimide(PE)was selected and combined with ammonium phytate(AP)to prepare flame-retardant cotton fabrics through a pad-dry-cure treatment.The structure, micromorphology, thermal performance, flame retardancy, burning behavior, antibacterial properties, mechanical properties, and hydrophobic properties of the flame-retardant cotton fabrics were characterized using various techniques, including Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, vertical flame test, cone calorimetry test, antibacterial activities, universal material testing machine, and water contact angle tester.[Results] The results indicated that the PE/AP coating was successfully deposited on the surface of cotton fabrics.The thermogravimetric analysis revealed that PE/AP did not alter the typical thermal degradation process of treated cotton fabrics.Although the initial thermal degradation temperature of Cotton/PE/AP was lower than that of untreated cotton fabrics, their char residues of Cotton/PE/AP in N2 at 700 ℃ increased to 32.5%, demonstrating improved thermal stability in high-temperature zone.Moreover, when the weight gain of Cotton/PE/AP reached 9.89%(by mass), it achieved a rapid self-extinguishment after the igniter was removed, with both the afterflame time and the afterglow time reduced to 0 s.The damaged length was 103 mm, and the LOI increased to 28.3%.Meanwhile, compared with untreated cotton fabrics, after adding PE/AP, the peak heat release rate of Cotton/PE/AP decreased from 124 kW/m2 to 90 kW/m2, and the total heat release decreased from 4.1 MJ/m2 to 3.4 MJ/m2.Additionally, after the flame-retardant treatment, smoke release was effectively mitigated.Compared with that of untreated cotton fabrics, the total smoke production of Cotton/PE/AP was reduced by 96.8%, indicating that PE/AP can effectively suppress the smoke release.In addition, Cotton/PE/AP exhibited an antibacterial rate of 99.99% against both Escherichia coli and Staphylococcus aureus, and its water contact angle was 103.2°, indicating improved hydrophobic performance.Furthermore, the mechanical properties of Cotton/PE/AP showed slight improvement.The breaking force increased from 308 N to 311 N in the warp direction, and the breaking force increased from 329 N to 332 N in the weft direction.Therefore, the breaking force of Cotton/PE/AP in the warp and weft directions was increased by approximately 1.0% and 0.9% respectively compared with that of untreated cotton fabrics.Additionally, compared with that of untreated cotton fabrics, the whiteness of Cotton/PE/AP decreased from 91.38% to 82.78%, representing a reduction of only 9.4%.Therefore, Cotton/PE/AP largely retained its whiteness compared with untreated cotton fabrics.[Conclusion] The results presented above demonstrated that the deposition of PE/AP endowed cotton fabrics with enhanced flame retardancy, antibacterial properties, and hydrophobic properties, while Cotton/PE/AP maintained fairly acceptable hand feel compared with untreated cotton fabrics.Furthermore, the PE/AP coating exhibited a certain inhibitory effect on the peak heat release rate and total smoke production.Overall, it demonstrates a great potential for application in multifunctional flame-retardant cotton fabric finishing.However, the study did not evaluate the wash durability of the treated cotton fabrics.Future studies should comprehensively explore the fabric characteristics such as water wash resistance to improve efficiency and broaden its potential applications in areas such as clothing, home textiles, and decoration.