Fully bio-based flame-retardant cotton fabrics via layer-by-layer self assembly of laccase and phytic acid

With the ever-increasing attention to eco-friendly flame-retardant finishing of cotton fabrics (CF), bio-based flame retardants have been urgently required. For this end, laccase (QM) and phytic acid (PA) were fabricated on CF via layer-by-layer self assembly. The successful deposition of binary coating on CF was characterized by FTIR and SEM-EDS. With the aid of biomass coating, the LOI value of CF/QM/PA was largely elevated to 43.0% with an increment of 129% as compared to pristine CF. Moreover, CF/QM/PA displayed self-extinguishing phenomenon upon removing the fire during the vertical burning tests, and the peak heat release rate (PHRR) of CF/QM/PA was remarkably dropped to 36 W/g from 310 W/g of CF with a reduction of 88.4%. Thermogravimetric analysis (TG) revealed that although the maximum thermal degradation rate of CF/QM/PA significantly reduced as compared to CF, the final char residue reached up to 39.0%. More importantly, in combination of the analyses of the gaseous products generated during the combustion process and the residual chars after combustion, it was proposed that QM/PA coating exerted flame-retardant activities both in the condensed phase and gas phase. Generally, this work provides a feasible and eco-friendly method for the flame-retardant finishing of cotton fabrics.