Thermogravimetric analysis was used to study the carbonization and flame retardation of an intumescent flame retardant(IFR) containing monohydroxyethyl melamine. Results showed that the IFR and the oxygen in air took part in the decomposition reaction of polypropylene and promoted it to form more thermostable carbon rich materials

leading to the increase of thermogravimetric residual ratio. However

burning tests showed that higher residual ratio and char yield did not mean better flame retardation for the IFR PPs with the same IFR content but different IFR composition.The flame retardation of the IFR PPs depended mainly on the composition of the IFR. It was found that the optimum composition of the IFR for flame retardation of PP was 1∶5 by mass for monohydroxyethyl melamine and ammonium polyphosphate.