Constructing Fireproof MXene-Based Cotton Fabric/Thermoplastic Polyurethane Hierarchical Composites via Encapsulation Strategy

Promising cotton fabric composites are designed to be protected by flame retardant thermoplastic polyurethane (TPU) composites for the next-generation fire-proof suit. Herein, we successfully constructed flexible cotton/TPU hierarchical composites, where a comfortable cotton internal layer was obtained by multiple dip coating of titanium carbide (MXene) and ammonium polyphosphate (APP)/TPU composites served as external layers. The flame retardant and mechanical properties of its cotton/TPU hierarchical composites were tuned by adjusting the dip coating circle. The obtained thermogravimetric analysis results of the TPU/APP/Cn system indicated that the char residue of MXene-based cotton/TPU hierarchical composites by third dip coating increased from 9.81 to 30.81 wt %. Notably, the hierarchical composites showed 87.2% and 65% reductions in the peak of heat release rate and total heat release, respectively, compared to pure TPU. Besides, their mechanical performance was improved significantly, e.g. the tensile strength, elongation at break, and toughness reaching 20 MPa, 400%, and 30.0 MJ/m 3, respectively. These properties improvements are due to the synergistic effect between MXene-based cotton and TPU/APP composites. This work offers a promising attempt for the design of flexible and multifunctional cotton/polymer hierarchical composites with brilliant flame retardancy and mechanical properties.