Synthesis of phosphorus, sulfur and silicon-containing flame retardant via thiol-ene click reaction and its use for durable finishing of cotton fabric

The article presents a very simple method of synthesis and application of a halogen and formaldehyde free, P, S and Si-containing flame retardant for the durable finishing of cotton fabric. The compound was obtained as a result of the thiol-ene click reaction. The compound was designed to have two functional groups: an alkoxysilyl group for cross-linking and binding to the cotton fabric, and a phosphate group to provide flame retardant properties. The flame retardant was applied to cotton fabric using the sol-gel method. According to the pyrolysis-combustion flow calorimetry (PCFC) technique, the use of the obtained silane for cotton treatment can reduce heat release rate (HRR) to almost 75% compared to the raw fabric. FT-IR analyses and SEM images indicate that impregnated cotton samples were covered with a layer of silanes. The SEM-EDS analysis confirmed successful modification of cotton fabrics. After 10 cycles of washing it was found that the created coatings are resistant to washing and retain their flame retardant properties.