Polyaniline/montmorillonite nanocomposites as an effective flame retardant and smoke suppressant for polystyrene

- We report a novel organic sulfates modified PANI/MMT flame retardant for PS.
- The agglomeration of MMT layers are remarkably improved by nanostructured PANI.
- PS/NPM nanocomposites can provide pronounced promotion in fire hazard reductions.
- The flame retardant mechanism of PS/NMP nanocomposites was studied.

Novel polyaniline (PANI)-montmorillonite (MMT) nanocomposites modified by sodium dodecyl benzene sulphonate (DPM) and 1,5-naphathalene disulfonic acid (NPM) were synthesized by a facile in situ polymerization to reduce flammability and toxicity of polystyrene (PS). The modification of organic sulfates can induce the polymerization of PANI and the exfoliation of MMT layers. PS/MMT, PS/DPM and PS/NPM nanocomosites are prepared by melt blending method with different MMT(DPM/NPM) loadings (1 wt%, 3 wt% and 5 wt%). The structure and morphology were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy, respectively. Cone calorimeter test, thermogravimetric and dynamic mechanical thermal analysis were employed to evaluate the heat and non-heat fire hazards of PS nanocomposites. The incorporation of MMT, DPM and NPM into PS matrix effectively improved the fire safety and the thermal stability. The heat release rate, total heat release, smoke production rate and CO production rate of PS nanocomposites were remarkably reduced. Among MMT, DPM and NPM, NPM with a composite nanostructure provided the best flame retardant and smoke suppressing performances. PS/NPM can provide pronounce promotion in fire hazard reductions. The promotion is attributed to the 3D network structure constructed by the exfoliated MMT layers and PANI chains that uniformly dispersed in PS matrix.