Synthesis of organic-inorganic hybrid flame retardant and its use in polyurethane composite fiber membrane

In this article, we presented an inventive organic-inorganic hybrid flame retardant, MPKG, by the strategic reaction of phytic acid (PA) with melamine (MA), gamma-aminopropyl triethoxysilane (KH550) and graphene oxide (GO). Subsequently, an MPKG/PU fiber membrane was fabricated through electrospinning, wherein MPKG was seamlessly incorporated into the PU spinning solution. The morphology and chemical structures of the flame retardants were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and x-ray photoelectron spectroscopy (XPS). The flame retardancy and resilience to soaping of the fiber membranes were assessed via the limiting oxygen index (LOI), thermogravimetric analysis (TGA), and microscale combustion calorimetry (MCC). Impressively, the results demonstrate a significant 38.8% reduction in total heat release (THR) for the MPKG/PU fiber membrane in comparison to pure PU fiber membrane. Moreover, the incorporation of MPKG leads to an increase in LOI from 18.8% to 21.5% for the PU fiber membrane, accompanied by a notable enhancement in char yield at 800 degrees C from 13.5% to 28.5%. These results underscore the augmentative impact of MPKG on the flame retardancy of PU fiber membrane. Remarkably, the MPKG/PU fiber membrane exhibits robust soaping resistance, with the LOI maintaining a level above 20% post-soaping.