The flame retardancy and smoke suppression effect of a hybrid containing CuMoO4 modified reduced graphene oxide/layered double hydroxide on epoxy resin

•A novel hybrid of RGO-LDH/CuMoO4 was synthesized by co-precipitation method.•RGO-LDH/CuMoO4 were well-dispersed in EP matrix according to TEM observation.•RGO-LDH/CuMoO4 has better flame retardancy and smoke suppression for epoxy resin.•The flame retardant mechanism of RGO-LDH/CuMoO4 was studied. The co-precipitation method was used to synthesize a hybrid with MgAl-layered double hydroxide loaded graphene (RGO-LDH). CuMoO4 was then introduced onto the surface of RGO-LDH to prepare a hybrid with CuMoO4 modified RGO-LDH (RGO-LDH/CuMoO4). The composition, structure and morphology of RGO-LDH/CuMoO4 were characterized by X-ray diffraction, Laser raman spectroscopy and Transmission electron microscope-energy-dispersive X-ray spectroscopy. It was found that the hybrid of RGO-LDH/CuMoO4 had been successfully prepared. The effects of flame retardancy and smoke suppression of epoxy resin were studied with added RGO-LDH/CuMoO4. Results showed that the PHRR and THR of the EP composite with RGO-LDH/CuMoO4 added were decreased dramatically. The char yield, LOI and UL-94 vertical burning rating of the EP composite were increased, with improved flame ratardancy. In addition, the SPR, TSP, and Ds,max of the EP composite were decreased drastically with added RGO-LDH/CuMoO4. Its improved flame retardancy and smoke suppression performance were due mainly to the physical barrier of graphene and LDH, and the catalytic carbonization function of LDH. Meanwhile, Cu2O and MoO3 generated from RGO-LDH/CuMoO4 in the combustion process helped enhance the production of char residue and raised the compactness of the char layer.