Flame-retardant natural textiles

International audienceTextile technologies have been metamorphosed over the past two decades, shifting technologically from conventional to multifunctional textiles [1]. A multi-layered textile with long-standing flame retardancy and electrical conductivity was prepared via layer-by-layer (LbL) coating fabrication. A coating of polyethylenimine (PEI), ammonium polyphosphate (APP), and a composite containing poly(aniline-co-melamine) and montmorillonite (MMT) were consecutively applied, and the resulting multi-layered fabrics was systematically analyzed by Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX) and thermogravimetric analysis (TGA). Flame retardancy analysis by pyrolysis-combustion flow calorimetry (PCFC) and a vertical burning test confirmed a significant fall in the heat release rate (HRR) by flax fabrics treatment. More interestingly, a very low peak of HRR (pHRR) of 15 W/g with respect to 234 W/g for untreated flax fabrics should be highlighted. Mechanistically, TGA measurements confirmed condensed phase flame retardancy, as reflected in a significant rise by 37% in the amount of residue of the treated fabrics compared to 19% for the untreated flax fabrics. The vertical burning test verified the formation of a fireproof multi-layered fabric. The conductivity of the flax fabric was in the range of 1-8×10-7 S/cm before burning, but surprisingly the fabrics remained conductive over 30 S. To give the product another dimension, a fully bio-based flame retradnat system using phytic acid amalgamated with a bio-phosphorus precursor was designed and applied on the flax fabric. The flame retardancy of the obtained samples was also investigated and compared with the last samples