Hybrid organic-inorganic hydrophobic and intumescent flame-retardant coating for cotton fabrics

Cotton fabrics have low limiting oxygen index which restricts their applications. In this study, a hybrid organic-inorganic intumescent flame-retardant, composed of polyethyleneimine (PEI) wrapped nanosilica (SiO2) and polyphosphoric acid (PPA), was coated onto cotton fabrics by layer-by-layer (LbL) assembly to improve flame retardancy of cotton fabrics. Water repellent agent REPELLAN FF was further coated on the LbL deposited cotton fabrics by the dip-pad-cure process to prepare flame-retardant and hydrophobic cotton fabrics. The SiO2-PEI/PPA/REPELLAN FF coated cotton fabrics were characterized by FT-IR, SEM, and EDX. Thermal properties, mechanical properties, flame retardancies, and hydrophobic properties of the coated cotton fabrics were investigated. The SiO2-PEI/PPA/REPELLAN FF coated cotton fabrics showed good flame-retardant and hydrophobic properties with a LOI of 28.2% and a contact angle of 142 degrees +/- 1 degrees, respectively.