Fire hazard suppression of intumescent flame retardant polypropylene based on a novel Ni-containing char-forming agent

Reducing the fire hazard of polypropylene (PP) is an important research direction in the fields of fire safety materials. In this article, a novel Ni-containing char-forming agent (TTPN) was successfully synthesized, using tris(2-hydroxyethyl) isocyanurate (THEIC), terephthalic acid, and nickel dihydrogen phosphate. Then, TTPN was combined with the silica-gel microencapsulated ammonium polyphosphate (OS-MCAPP) to prepare intumescent flame retardant PP composites. From the results of the limiting oxygen index (LOI) test and cone calorimeter, the composite containing 30% IFR (OS-MCAPP: TTPN = 3:2) shows the highest LOI value of 33.5%, and its peak heat release rate is 275.5 kWm(-2), decreased by 79.0% and 37.4% than those of pure PP and the composite containing the char-forming agent without Ni. Meanwhile, the composite containing TTPN present the best smoke and CO2/CO suppression. The results indicate that TTPN has an excellent ability to dramatically reduce the fire hazard of PP.