Hydrophobic and flame-retardant finishing of cotton fabrics for water-oil separation

Fabrics with high flame-retardancy have been extensively applied for numerous applications including textile, garments, automobile industries, pants, shirts, suits bed sheets, and indoor decorations. Coatings consisting of ammonium hexametaphosphate (NH4-HMP), laponite (LAP), and hexadecyltrimethoxysilane were synthesized through sol-gel method; they were then employed on the cotton fabrics to enhance their hydrophobicity and flame retardancy. The influences of LAP concentration on fire-retardancy of the samples were evaluated. The combustion behavior, morphological structures, thermal stability, and hydrophobic properties of the cotton fabrics were studied. Results indicated the excellent flame retardant property of the treated cotton fabrics as they immediately extinguished upon removal of the flame source. The limiting oxygen index of the treated cotton was enhanced to 29% in comparison to that of the pure one (19.5%). The findings also indicated that a higher concentration of LAP is useful for improving flame retardancy of the coated substrate. In addition, the hydrophobicity of the fabric surface was measured by a water contact angle of 138 degrees, while its superoleophilicity was assessed by an oil contact angle of 0 degrees. To separate water-oil mixtures, the as-prepared cotton sample was utilized as operative substances. Overall, in this study a facile technique is provided for preparing cotton fabrics with considerably enhanced flame retardancy and superior self-cleaning features toward different fluids making them suitable as a promising candidate for water-oil separation.