Facile fabrication of ultradurable flame-retardant and hydrophobic cotton fabric with P/N-rich maltodextrin derivative and octadecyltrimethoxysilane

Flame-retardant and hydrophobic cotton fabric provides protections from fire, stain and bacteria in daily life. However, it is still a great challenge to achieve ultrahigh durability via a green and facile technology. Herein, we synthesized a reactive P/N-rich maltodextrin derivative (PM), and reported a facile dipping-baking strategy to fabricate ultradurable flame-retardant and hydrophobic cotton fabric with PM and octadecyltrimethoxysilane (OTMS). The acids released from PM not only reacted with cellulose during baking, but also catalyzed the hydrolysis-polycondensation of OTMS and silylation reaction of cellulose. Thanks to the P/N/Si synergy and the existence of polyalkylsiloxane coating, treated fabric exhibited outstanding flame retardancy and hydrophobicity with a limiting oxygen index (LOI) of 34.7% and a water contact angle (WCA) of 143.3 degrees. The chemical crosslinkings in PM-cellulose and OTMS-cellulose imparted ultrahigh durability to treated fabric. The LOI and WCA of treated fabric still reached 27.2% and 127.9 degrees after 50 harsh washing cycles, respectively. Moreover, the WCA still maintained above 125 degrees after 3000 intense friction cycles or soaked in strongly acidic/alkaline solution for 3 days. This work not only provides a new idea to synthesize biobased reactive flame retardant, but also a feasible and sustainable strategy for fabricating ultradurable hydrophobic and flame-retardant cotton fabric.