Nanocomposite based on polystyrene/polyamide blend and bentonite: Morphology, thermal, and nonflammability properties

Novel organomodified nanoclay (bentonite) was reinforced in polystyrene, polyamide, and polystyrene/polyamide blend matrix to develop a series of nanocomposites using a solution processing technique. Modification of bentonite nanoclay was performed via an ion-exchange method with l-serine amino acid. Properties of polystyrene/modified bentonite, polyamide/modified bentonite, and polystyrene/polyamide/modified bentonite nanocomposites were studied using Fourier transform infrared spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, and cone calorimetry techniques. A unique honeycomb-like pattern was observed for polystyrene/polyamide blend with 0.5 g modified bentonite content. The morphology analysis revealed a co-continuous structure in which nanoclay particles were trapped. The polystyrene/polyamide/modified bentonite nanocomposite also showed fine improvement in thermal properties of the system, that is, initial decomposition temperature = 309-321 degrees C and maximum weight loss temperature = 390-400 degrees C. Glass transition temperature (351-385 degrees C) of the series was also higher than the polystyrene/modified bentonite and polyamide/modified bentonite series. Increasing nanoclay content decreased the peak heat release rate of polystyrene/polyamide/modified bentonite 0.5 nanocomposite to 145 kW m(-2), indicating improvement in nonflammability. Moreover, the blend and nanoclay series possess better flame retardancy than the blend and other nanocomposite series developed.