Alkoxysilyl derivative of carbamoylphosphonate as a flame retardant modifier of cotton fabrics

This research describes the synthesis of a silane derivative containing phosphorus and nitrogen atoms, leveraging their synergistic flame retardant effect through the incorporation of a P-H bond to the isocyanate moiety. The synthesized silane featured alkoxysilyl groups, facilitating permanent bonds with the cotton fabric surface via hydrolysis. Cotton fabrics were modified using silane solutions of varying concentrations (2.5 %, 5%, and 10%) through a dip-coating process to determine the effect of the modifier amount on fabric properties. The modified fabrics were subjected to FT-IR, TGA, SEM, and EDS analyses, as well as microcalorimetric and LOI tests, to assess changes in flammability. FT-IR, SEM/EDS, and add-on analyses confirmed effective coverage of the cotton fabric with the flame retardant. Thermogravimetric tests indicated a significant reduction in the mass loss rate during thermal degradation. LOI analyses demonstrated a decrease in flammability (increase in LOI value), while microcalorimetric tests showed a substantial decrease in the heat release rate, correlating with increased modifier concentration on the fabric surface. Post-washing analyses revealed that, although some of the modifier was washed out, the samples still retained reduced flammability.