Polyaniline-coupled graphene/nickel hydroxide nanohybrids as flame retardant and smoke suppressant for epoxy composites

Graphene-polyaniline/nickel hydroxide ternary hybrid (RGO-PANI/Ni(OH)(2)) was synthesized and incorporated into epoxy resin (EP) to improve the fire retardant property. Thermogravimetric analysis results showed that the RGO-PANI/Ni(OH)(2) nanohybrid could catalyze the thermal degradation of epoxy matrix that was essential to trigger the char formation. The char yield of the RGO-PANI/Ni(OH)(2)/EP composite was improved compared with that of the samples with graphene and polyaniline only. With 3.0-wt% RGO-PANI/Ni(OH)(2), significant reduction in peak heat release rate (40%) and peak smoke production rate (36%) was observed in the cone calorimeter tests. Thermogravimetric analysis/infrared spectrometry (TG-IR) results indicated that the flammable volatiles of the RGO-PANI/Ni(OH)(2)/EP composite was reduced compared with those of the EP and RGO-PANI/EP. The superior flame retardant and smoke suppressant behaviors of the RGO-PANI/Ni(OH)(2) nanohybrid over RGO-PANI were attributed to the combination of good barrier effect of graphene with catalytic ability of char formation of PANI and metal hydroxide.