Turn Waste into Treasure: Novel High-Efficiency, Reactive, and Sericin-Based Intumescent Flame Retardant for Cotton Fabrics

Abstract

Sericin is a byproduct generated during silk processing, which generates significant environmental concerns due to its environmental pollution problem. However, such a protein structure contains an abundance of active functional groups and has the potential to be used as a biomass flame retardant. In this work, we first synthesized a sericin-based intumescent flame retardant (IFR), which was subsequently applied onto cotton fabric through chemical grafting. The resulting IFR-treated fabrics demonstrate high flame retardant efficiency with exceptional durability. Especially, the cotton fabric treated by a 10% concentration of an IFR solution possesses a remarkable increasing limiting oxygen index value of 30.57% and a quick self-extinguishing property. Moreover, the microscale cone calorimeter test shows that the peak heat release rate and total heat release values are greatly reduced by 82.79% and 73.77% compared with the pure cotton fabric. Remarkably, the IFR-treated fabrics exhibit excellent washing resistance, as evidenced by their ability to maintain a self-extinguishing ability in the vertical burning test even after undergoing multiple wash cycles. Also, the samples have no formaldehyde residue and meet the requirements of green environmental protection. This work not only expands the application range of sericin but also presents a novel method for preparing efficient and durable IFR for cotton fabrics, which effectively balances functional requirements and offers promising prospects for practical use.