Abstract: Abstract:The effect of boron in the intumescent flame retardant PP was studied by horizontal combustion test, thermal analysis and cone calorimeter. The thermal analysis showed that KDIFR made the PP’s char residual increase and heat release reduce, but the introduction of boron made the char residual decrease and heat release increase slightly. Cone calorimeter graphs indicated the KDIFR significantly reduced the heat release rate, total heat release, and CO2, CO emissions in the combustion process of PP, which was promoted by boron, but was weakened as the combustion process continued. In a word, experiments results showed that KDIFR changed the PP’s typical polyolefin type combustion to fiber type combustion, which was promoted by boron, and slowed down the flame propagation, and had more prominent flame retardance.

Key words: Key words: polypropylene, boron, intumescent flame retardant, thermal analysis, cone calorimeter