Preparation and properties of FR-PP with phosphorus-containing intumescent flame retardant

A novel phosphorus-containing intumescent flame retardant, triazine oligomer poly (2-morpholinyl-4- pentaerythritol phosphate-1,3,5-triazine) (PMPT), was used to improve the flame retardancy of PP. Effects of PMPT content on the thermal stability, mechanical properties and flammability of PP were discussed, respectively. The morphology of the char residue was observed by SEM. The thermogravimetric (TGA) curves showed that adding PMPT reduced the initial thermolysis temperature of flame retarded PP (FR-PP) while enhanced the thermal stability at high temperature. The slight decline on the mechanical properties of FR-PP suggested that the compatibility of PMPT and PP was good. PP/30% PMPT composite can achieve UL-94 V-0 rating, which revealed that PMPT was an efficient monocomponent intumescent flame retardant. There were many cavities on the compact char layer of FR-PP and the gases generated from PMPT was a critical factor for the flammability properties of FR-PP.