Phytic acid, widely present in plants, showed to provide a wash-durable flame retardant for cotton. Phytic acid is the natural phosphorus storage molecule in plants and seeds. Cotton and nylon/cotton blend (Nyco) fabric samples were surface functionalised with 1,10-carbonyldiimidazole and with ehylenediamine, dipped in aqueous phytic acid solution and dried. This reacted diamine and phytic acid to cellulose in cotton by carbamate bonds, leading to an increase in fabric phosphorus content from c. 1% to 4.3% and of nitrogen from 3.3 to 5.7% Total heat release from the cotton fabric was reduced by nearly 85% (33% reduction for Nyco 50/50) and both fabrics were self-extinguishing after treatment. Flame retardancy was not significantly deteriorated after five laundry cycles (AATC 135) showing that the treatment is wash durable. However, the treatment did significantly deteriorate fabric breaking strength.
“Covalent functionalization of cellulose in cotton and a nylon-cotton blend with phytic acid for flame retardant properties”, S. Thota et al., Cellulose 27, pages11–24(2020) https://doi.org/10.1007/s10570-019-02801-6