Institute for Color Science and Technology (ICST) Progress in Color, Colorants and Coatings 2008-2134 18 4 2025 10 01 Evaluation of Fire-Retardant Efficacy and Comfort Properties of Treated Polyester/Cotton and Polyester/Viscose Fabrics 431 443 82087 10.30509/pccc.2025.167452.1354 EN F. Afkhami Department of Textile Engineering, Yazd University, P.O. Box: 89195- 741, Yazd, Iran M. S. Ahmadi Department of Textile Engineering, Yazd University, P.O. Box: 89195- 741, Yazd, Iran M. Khajeh Mehrizi Department of Textile Engineering, Yazd University, P.O. Box: 89195- 741, Yazd, Iran Journal Article 2025 01 25 This study evaluates the fire-retardant (FR) performance of polyester/ cotton (PC) and polyester/viscose (PV) fabrics treated with an alkyl phosphate ester-based FR agent at concentrations of 100, 150, and 200 g/l, followed by curing at 200 °C for 60 or 180 s. Untreated fabrics burned completely, whereas the FR treatment reduced flammability significantly, with char lengths of 2 cm (PC200C60t) and 0.4 cm (PV200C180t). The limiting oxygen index (LOI) increased to 22 % (PC) and 23 % (PV), confirming enhanced flame resistance. EDX and FTIR analyses confirmed successful FR deposition, showing increased phosphorus and nitrogen content alongside the formation of ester bonds (O-H, C=O, O-C-H). Bending stiffness rose by 29 % for PV200C180t, while wrinkle recovery improved by 27.9% (PC) and 23.3 % (PV). Air permeability decreased by 41.5 % (PC) and 59.5 % (PV), and water permeability (PDA) declined by 15.74 % (PC) and 35.61 % (PV). The treatment achieves an effective balance between flame resistance and wearability, demonstrating strong potential for protective textiles. https://pccc.icrc.ac.ir/article_82087_b212431fb562ac8d84c5f7b52b8ae932.pdf