Flame-retardant effect of tannic acid-based intumescent fire-retardant applied on flammable natural rubber

Tannic acid (TA) is a natural phenolic compound abundant in plants. Its characteristics of low combustion and good absorption make it useful in the flame retardant field. On this basis, a new expansive flame retardant system (ACT) composed of ammonium polyphosphate (APP)/TA functional clay (CT) was used to study the synergistic flame retardancy and smoke suppression of natural rubber (NR). Because of their unique flame retardancy and better mechanical properties compared with the traditional expansive flame retardant system (IFR), new flame retardants have attracted much attention in various fields. The results of the cone calorimeter showed that the ACT system can significantly influence the decomposition behavior of NR and form a highly graphitized and phosphorous carbon layer to protect the composite material, thus a synergistic effect is produced on the flame retardancy and smoke suppression performance of the composite material. In addition, within the effective additive quality range of the ACT system, TC can give the NR composite excellent mechanical properties. The ACT systems give synergistic effects on the flame retardancy and smoke suppression properties of NR.