Synergistic effects of a highly effective intumescent flame retardant based on tannic acid functionalized graphene on the flame retardancy and smoke suppression properties of natural rubber

Tannic acid (TA), natural phenolic compounds abundant in many plants, exhibit low flammability and good absorbility because of multidentate properties. Based on it, a novel intumescent flame retardant (IFR) system (AGT) that consists of ammonium polyphosphate (APP)/TA functionalized graphene (TGE) presents synergistic flame retardant and smoke suppression for natural rubber (NR) due to the dual flame retardant functions of each component. The novel AGT system is of interest to a variety of fields because of its distinct flame retardant and relatively good mechanical properties in comparison to traditional IFR system. Cone calorimeter results reveal that the AGT system could clearly change the decomposition behavior of NR and form a highly graphitized and phosphorous-containing carbonaceous structure char layer on the surface of the composites, consequently resulting in synergistic effects on the flame retardancy and smoke suppression properties. Moreover, TGE endows NR composite excellent mechanical properties within an effective additive mass of AGT system.