Eco-Friendly, Thermal Resistant Cotton Fabric Enhanced with Nano Zinc Borate Powder

The easy burning of cotton fabrics, which have the widest usage area among natural fibers, is a serious problem. Thus, treatment with an environmental friend flame retardant material is essential for cotton fabrics. Zinc borates are multifunctional fire retardants. They can act as smoke suppressor, flame retardant and spark suppressor. Since they are non-toxic and environmental friend materials, they are ideal flame retardants for fabric treatment. In this study, nano-sized zinc borate (ZnO·3B2O3·7H2O) was synthesized and cotton fabric was treated with zinc borate powder with a novel method. Zinc borates are slightly soluble in water. They were dissolved with aid of ammonia as zinc ammonia borate complexes and were recrystalised on the cotton fabric fibers through the evaporation of ammonia. The burning resistance of treated cotton fabric was investigated. The hardness, hydrophobicity, smoke suppression and burning resistance of untreated and treated cotton fabrics were compared. Since zinc borates have smoke suppression feature, a more slight smoke was observed and a higher rate of carbonization occurred during combustion test of treated cotton fabric compared to the untreated cotton fabric. In addition, the burning rate was reduced from 2.26 cm/s to 1.26 cm/s.