Structural and thermal properties of polystyrene nanocomposites containing hydrophilic and hydrophobic layered double hydroxides

Zn-Al layered double hydroxide (LDH) was synthesized and modified using sodium dodecyl benzene sulfonate (DBS). Hydrophilic and hydrophobic LDHs were applied as fillers in a free-emulsion polymerization of styrene monomer, which enhance their thermal stability, and strengthen their structure. In order to increase structural stability we modified the surface of LDH with anionic surfactant and examined its effect on the exfoliation in the polystyrene (PS) matrix. The structure of polystyrene-LDH nanocomposites was investigated by X-ray diffraction pattern technique (XRD), and small angle X-ray scattering (SAXS). Furthermore, thermal analysis (TGA and DSC) was evaluated and the prepared nanocomposites show significantly improved thermal stability at higher temperature. Both XRD and SAXS results confirmed the totally delaminated state of the LDH in the polymer matrix. It was established that the hydrophilic filler has a better exfoliation effect than the hydrophobic LDH in the hydrophobic polymer structure. © 2013 Elsevier B.V.