Synthesis and characterization of phosphonium-based ionic liquid anchored graphene functionalized ZnAl-ldh nanocomposite for polystyrene applications

In this work, polystyrene (PS) nanocomposites were synthesized by incorporating layered double hydroxide (LDH) functionalized with graphene (G) and phosphonium-based ionic liquid (PCL). These nanofillers were added to PS at varying weight contents of 5%, 10%, and 15% to evaluate their effect on thermal stability and mechanical properties. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA) of the nanomaterial exhibited the successful intercalation of graphene and PCL into the ZnAl-LDH matrix. The PS nanocomposite exhibited improved thermal stability and mechanical properties, attributed to the synergy between the functionalized LDH and graphene. The addition of a mere 5% of nanofillers improved the limiting oxygen index (LOI) from 18.51 to 19.11 for pure PS and PS-LDH-G-PCL, respectively. Although the enhancement in the LOI was modest, the nanocomposite (PCL-G-LDH) demonstrated excellent char-forming abilities and increased graphitization during combustion, contributing to flame retardancy and less smoke production and dripping. The findings demonstrate the successful intercalation of graphene and PCL into ZnAl-LDH interlayers and their potential applications as flame retardants for PS.