Phosphorylated octa-aminopropyl POSS grafting on proanthocyanidin interface decorated 2D MXene for enhanced flame-retardancy of cotton fabric nanocomposites.

Two-dimensional (2D) nanosheet materials (MXenes) have unparalleled advantages in the field of flame-retardant multifunctional composites, but their dispersibility, flame retardancy and compatibility with the matrix are poor and need to be enhanced. In this research, we employed interfacial decoration and grafting modification to firstly introduce proanthocyanidins (PCs) onto MXenes surface (forming PC-MXenes) to increase the number of available active sites. On this basis, phosphorylated A-POSS was grafted onto PC-MXene (resulting in PAP@P-MXene) via a one-pot method, organic-inorganic hybrid flame-retardant PAP@P-MXene nano-coatings were subsequently constructed on the surface of cotton fabrics via an immersion method, and their structure-property relationships were verified. Thermogravimetric analysis (TGA) results revealed that PAP@P-MXene displayed a high char residue content of 32.0 % at 800 °C, illustrating its pretty good fire-safety properties. Typically, the residual char amount of coated cotton fabric with 12 wt% PAP@P-MXene (C-PAP@P-MXene-3) under a N atmosphere was as high as 37.1 %. Additionally, the limiting oxygen index (LOI) increased to 31 %, while the peak heat release decreased by 79.83 %. C-PAP@P-MXene-3 also displayed a UL-94 V-0 rating and self-extinguishing ability, all of which demonstrated excellent fire safety performance. The unique 2D nanosheet structure of MXenes, along with their innovative structural design and synergistic flame-retardant strategy, endows the nanomaterials with good dispersibility and flame-retardant effects, which has led to the development of new flame-retardant strategies and expanded the potential applications of MXene materials.