Eco-friendly flame retardant and smoke suppression coating containing boron compounds and phytic acids for nylon/cotton blend fabrics

The flammability of nylon/cotton blend fabrics poses a great potential to cause fire hazard. A bio-based boron contained flame retardant (PBN) in this work was obtained, and then was applied in association with phytic acids to nylon/cotton blend fabrics using a facile dipping and nipping method. The flame retardancy of the fabric was improved significantly with reduced phosphorus content at the presence of PBN. The LOI of the PBN treated blend fabric was 30.1%, and the peak heat release rate (pHRR) and total smoke production (TSP) were decreased by 46.0% and 71.8% compared with that of control blend fabric in the cone calorimeter test. The analysis of the char residue proved the polyphosphoric acids in the flame retardant accelerated the formation of the char, while the ceramic boron structure remained in the char to stabilize the char layer. Moreover, it was suggested that the release of inert gases, such as NH3 and H2O diluted the combustible volatiles in the gas phase. This work proposes a possibility for the production of bio-based nylon/cotton blend fabrics with flame retardancy.