The flame retardancy and smoke suppression effect of heptaheptamolybdate modified reduced graphene oxide/layered double hydroxide hybrids on polyurethane elastomer

A MgAl-layered double hydroxide loaded graphene hybrid (RGO-LDH) was prepared through the co-precipitation method, and then heptaheptamolybdate (Mo7O246−) modified RGO-LDH hybrid (RGO-LDH/Mo) was synthesized by the ion exchange method. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectra, Laser Raman spectroscopy (LRS) and Transmission electron microscop (TEM) micrograph results showed the RGO-LDH/Mo was synthesized successfully. RGO-LDH/Mo was added into the polyurethane elastomer (PUE) for improving the flame retardancy and smoke suppression properties. The results showed that the char yield of PUE with RGO-LDH/Mo was increased significantly compared with pure PUE. The peak heat release rate and the maximum smoke density of the PUE composites decreased drastically. The reasons were attributed to the physical barrier of graphene and LDH, and the metal oxide generated from LDH could restrain the diffusion of inflammable gas. Meanwhile, MoO3 formed in the decomposition process of RGO-LDH/Mo promoted the catalytic carbonization and smoke suppression effect.