Study on Flame Retardancy of Polypropylene/Nano SiO_2 Composites

An intumescent flame-retardant was prepared by compounding 1,3,5-tri(5,5-dimethyl-1,3-dioxacyclophosphorinane phosphonate) benzene(FR),ammonium polyphosphate(APP),and nano-silica,and used in polypropylene(PP).Testing through limiting oxygen index,horizontal burning test,thermo gravimetric analysis(TG),and cone calorimeter showed that the compound flame-retardant increased the limiting oxygen index,horizontal burning rate,thermal stability,and residual char,and decreased the heat release rate.When the weight ratios of FR/APP/SiO2 were 15/7/3 and its content was 25 %,limiting oxygen index of 29.4 % and horizontal burning rate of FH-1 were obtained.