Abstract:In this article, the synergistic effects of cerium dioxide(CeO2) on the intumescent flame retarding epoxy composites were investigated. The introduction of CeO2 into the flame retarding composite enhances the limited oxygen index (LOI) value obviously. The flame retarding formulation with 1% of CeO2 has the excellent flame retardancy with the LOI value of 28.8%. The introduction of CeO2 decreases the initial temperature of flame retarding materials and improves the thermal stability and the integration of char residue. Meanwhile, the graphitization degree of char residue was observed by Raman spectroscopy. With addition of CeO2, the flame retarding formulation has a lower ID/IG which results from formation of the compact and dense char. Added CeO2 into flame retarding epoxy composites results in enhancement of the composites flame retardancy and formation of the compacted and dense char.