Thermal behavior of composites of PS-LDH (Mg-Al) modified with SDB and SDS

Abstract

Nowadays there is an increasing number of studies involving the use of fillers or additives for polymeric materials, in particular polystyrene, as flame retardants. Starting from this principle, this paper compares the thermal performance of composites of polystyrene/double layered magnesium-aluminium hydroxide (PS-LDH [Mg-Al]) compared to pure polystyrene. Compounds were prepared with LDH, chemically modified with sodium dodecyl sulphate (SDS-Na) or sodium dodecylbenzene sulfonate (SDB-Na). The synthesis of these additives (SDS-LDH and SDB-LDH) was carried out by the coprecipitation method and inserted via the PS dissolution in chloroform. The compounds were characterized by X-ray diffraction and Fourier transform infrared spectroscopy, where the first method proved the intercalation of the SBD/SDS with LDH and the second confirms the presence of the characteristic groups in LDH. Thermal properties of the composite were evaluated by thermo gravimetric analysis. The results showed that the modified PS-LDH behaves better than pure PS, it has higher thermal stability. Comparing them in a mass loss of 50%, the PS-LDH-SDS showed better results compared to pure PS, with a gain of approximately 44 ºC in the thermal decomposition temperature.

Keywords:
thermal behavior; polystyrene; lamellar double hydroxide; chemical modification