Construction of super-hydrophobic, highly effective flame retardant coating for cotton fabric with superior washability and abrasion resistance

In order to meet the rapidly growing demand of multi-functional fabric, a super-hydrophobic flame retardant coating for cotton fabric with superior washability and abrasion resistance was prepared. Flame retardant finishing agent P, P-diphenyl-N-(3-(trithoxysilyl) propyl) phospinic amide (DPTES) and hydrophobic finishing agent polydimethylsiloxane @silicon dioxide (PDMS@SiO2) were fixed on the surface of cotton fabric by a simple sol-gel technology in combination with convenient brush-coating process. The coated cotton fabric was capable of self-extinguishing a flame, and the Limiting Oxygen Index (LOI) increased from 18.0% for the control cotton fabric to 26.0% for the treated one at weight gain of 30.3%. The water contact angle (WCA) of C3-PDMS-silica is around 154°, and the slip angle is 8°. In addition, the treated cotton fabric exhibits anti-washing and self-cleaning ability due to the superhydrophobic feature and superior friction resistance. The C3-PDMS-silica sample with excellent char-forming ability, as shown by thermogravimetric analysis (TGA), leading to outstanding flame retardancy. A composite char layer was constituted with char residues and ceramic layer during the combustion of inorganic silicon, which plays the role of heat insulation and flame retardant.