Intumescence: An effect way to flame retardance and smoke suppression for polystryene

An intumescent flame-retardant (IFR) system, which was comprised of a novel carbonization agent (CA) and ammonium polyphosphate (APP), was prepared for general purpose polystyrene. Thermal degradation and flame retardance of the PS/IFR composites were studied. The results of LOI and UL-94 test showed that when the content of APP and CA was 22.5 and 7.5 wt%, respectively, the LOI value of PS/IFR composite was 32.5%, and a V-0 classification could be achieved. The TGA data indicated that there was a synergistic effect between CA and APP. The cone calorimeter data showed that the heat release rate (HRR), the total heat release (THR) and the mass loss rate (MLR) were reduced largely with the addition of IFR. Some cone calorimeter data, such as smoke production rate (SPR), total smoke production (TSP) and carbon monoxide production (COP), revealed that the IFR could greatly suppress the generation of the smoke during the material flaming. The study on the flame-retardant mechanism of IFR indicated that a steady structure containing P-O-C was formed due to the reaction between APP and CA. The mechanical properties of PS and PS/APP/CA3:1 were also investigated, and the results showed that, compared to those of the neat PS, the tensile strength and the flexural strength of the PS/IFR composite decreased to a certain extent.