Posted on 07/09/2023 in Fire Safety 2023
Bio-based intumescent PIN FR coating for NYCO

Nathalie Vest, Texas A&M University

Nylon-cotton fabric (NYCO) was multi-layer coated with phytic acid, chitosan and tannic acid, achieving self-extinguishing with 17% weight added. NYCO is widely used in military uniforms and workwear, but has high flammability because of interaction between the two fibres in fire. 50/50 NYCO was primed with polyethylenimine to impart a positive charge then soaked in solutions of bio-based phytic acid (PA), chitosan (CH) and tannic acid (TA), then soaked with repeated quadrilayers CH-PA-CH-TA, rinsed between each treatment. After 15 quadrilayers the textile was dried at 70°C. This resulted in a c. 17% weight increase, nearly six times higher than with 30 bilayer coatings of CH-PA or CH-TA. This high deposition rate, and colour change with the three components suggests chemical reactions between them. The 15 quadlayer PA-CH-TA coated NYCO was self-extinguishing in the 12s Vertical Flame Test and showed >50% reduction in peak heat release rate compared to control (uncoated), 8% lower than CH-PA coated.

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