LAUSR

Abstract ZnAl layered double hydroxide (ZnAl LDH) was synthesized via a facile hydrothermal method and then hybridized with the nitrogen and phosphorous co-doped graphene quantum dots at mild conditions. The structure and morphology of the prepared ZnAl LDH-NPGQD were characterized in detail by multiple techniques and then introduced into the polyacrylonitrile (PAN) matrix by solvent blending method. Subsequently, thermal stability, flame retardancy, fire behavior and fire hazard of the nanocomposite as well as structure of the residual char were investigated by thermogravimetric analysis (TGA), UL-94 vertical burning test, cone calorimetry and FE-SEM, respectively. The PAN/ZnAl LDH-NPGQD nanocomposite exhibited significantly higher flame retardancy and smoke suppressant capability in addition to lower fire hazard properties in comparison to the neat PAN. Moreover, incorporation of the ZnAl LDH-NPGQD into the PAN matrix increased the residual char from 0% for neat PAN to 14% for PAN/ZnAl LDH-NPGQD. These improvements were deduced to the ability of the ZnAl LDH-NPGQD to contribute in formation of stronger and larger protective char barrier layers.