Thermal Stability Evaluation of Polystyrene-Mg/Zn/Al LDH Nanocomposites

Abstract

A series of samples of Mg/Zn/Al LDHs (layered double hydroxides) materials was prepared by the co-precipitation and urea hydrolysis methods. They were modified with organic surfactants (acrylate and oleate anions) and characterized by X-ray diffraction, which corroborated the intercalation of anionic species into the interlayer space. The hydrophobized materials were incorporated at low contents (10 and 15 wt.%) to polystyrene, which was synthesized by emulsion polymerization techniques. The polymeric composites were analyzed by thermogravimetry to determine the decomposition temperature. The results demonstrated that the materials with Zn presented the greatest increment in the degradation temperature (7 °C < T < 54 °C). Moreover, the Friedman, Flynn−Wall−Ozawa, and Coats−Redfern models were compared to obtain the kinetic parameters of degradation process. The obtained order of decomposition of the Coats−Redfern model showed that the decomposition process occurs in at least two stages. Finally, the addition of environmentally friendly modified Layered Double Hydroxides (LDH) nanomaterials to the polystyrene (PS) matrix allowed for obtaining polymeric composites with higher thermal stability, retarding the decomposition process of PS.

Keywords

• polystyrene
• layered double hydroxides
• hydrophobization
• nanocomposites
• degradation temperature
• decomposition kinetic