The fabrication of flame-retardant viscose fabrics with phytic acid-based flame retardants: Balancing efficient flame retardancy and tensile strength

Viscose fabrics have been widely used in various applications, but their potential fire hazard has been a concern. To address this issue, improving the flame retardancy of viscose fabrics has become a significant priority. Phytic acid (PA) and xylitol were used to create a novel flame retardant, PAXY. PAXY was finished on viscose fabrics by pad-dry-curing process, and the performance of coated viscose fabrics was investigated. The results showed that the limiting oxygen index value of PAXY13–100 (fabrics finished with a 100 g/L flame-retardant solution and the flame retardant synthesized by a 1: 3 M ratio of PA to xylitol) reached 32.8 % and the heat release rate value was decreased by 77 %. Based on the findings from the analysis of both the gas phase and condensed phase products, PAXY promoted the dehydration of viscose fabrics to produce a denser char layer, which inhibited the production of flammable gases. Surprisingly, the breaking force retention of PAXY13–100 reached 90 % in warp and 114 % in weft. Compared with that of 100 g/L PA-treated fabrics, the breaking force of PAXY13–100 increased by nearly 400 %. This work provides a new strategy for PA-based flame-retardant finishing with the synergy of flame retardancy and breaking force retention.