Reasonable multi-functionality of cotton fabric with superior flame retardancy and antibacterial ability using ammonium diphosphate as cross-linker

Ammonium phosphates have been proven to be efficient and durable flame retardants for cellulose fabric. However, a facile process for their multifunctional flame-retardant modification has not yet been reported. In order to achieve this goal, we synthesized an ammonium diphosphate of ethylene glycol (AP) and used it as a crosslinker to fabricate flame-retardant and antibacterial cellulose fabric with a dihydroxyl N-halamine precursor (BD) via a one-pot process. The AP/BD modified fabric exhibited superior flame retardancy, with a LOI value of 32.9% and self-extinguishing behavior at only 11.0% weight gain. The heat release was significantly inhibited, with an 81% reduction in peak heat release rate (PHRR) and a 60% reduction in total heat release (THR). Furthermore, the modified fabric maintained its self-extinguishing properties even after undergoing 50 washing cycles, demonstrating excellent washing durability with a LOI value of 30.5%. In addition to its outstanding flame retardancy, the AP/BD modified fabric also displayed excellent biocidal efficacy due to the formation of N-Cl bonds through simple bleaching treatment. All inoculated bacteria were killed within just 5 min of contact without any noticeable dissolution occurring. Moreover, the oxidative chlorine that acted as an antibacterial factor could be recharged after long periods of storage and washing. Importantly, no significant changes in whiteness, air permeability or hand feeling were observed after the AP/BD modification process. Therefore, this work presents a common and facile approach for preparing highly-efficient flame-retardant cellulose fabrics with multifunctionality.