Melt Blended Polystyrene/Layered Silicate Nanocomposites: Effect of Clay Modification on the Mechanical,Thermal,Morphological and Viscoelastic Behavior

Abstract

Polystyrene (PS)/layered silicate nanocomposites are prepared by the melt blending technique. Na-MMT is modified with stearyltrimethyl ammonium chloride to evaluate the effect of clay modification on the performance of the nanocomposites. A comparative account with the nanocomposites prepared using commercial clay cloisite 20A (C20A) has been presented. The effect of addition of untreated and treated clays on the morphological, thermal, mechanical, and dynamic mechanical properties of PS matrix has been studied. The dispersion characteristics of the clays and the formation of tactoids within the matrix polymer is investigated through transmission electron microscopy (TEM) analysis. X-ray diffraction (XRD) studies confirm an increase in the clay gallery spacing in the treated clay nanocomposites. Thermal measurements employing differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA) are carried out to evaluate the effect of addition of nanoclays on the T_g and thermal stability of PS matrix. C20A-PS nanocomposites exhibit optimum performance at 3% clay loading. Mechanical tests reveal an increase of tensile, flexural, and impact strengths to the tune of 83, 55, and 74%, respectively. Further, dynamic mechanical analysis (DMA) shows a substantial increase in the storage modulus of PS in the treated nanocomposites.

Keywords

clay polystyrene XRD TEM DMA

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