Structure and dynamic mechanical properties of highly oriented PS/clay nanolaminates over the entire composition range

A series of highly oriented model polymer/clay nanocomposites (nanolaminates) are prepared via a newly developed solvent deposition process with compositions ranging from neat polymer to neat organoclay. Morphology is analyzed via scanning electron microscopy (SEM) and wide-angle X-ray diffraction (WAXD) while thermogravimetric analysis (TGA) is used to confirm composition and solvent removal. Dynamic mechanical analysis (DMA) is used to examine the trends in stiffness and damping properties as the composition is shifted from polymer-rich to polymer-starved. The role of the organoclay modifier in determining the structure and properties of these nanolaminates is also reported. Experimental moduli are compared to relevant micromechanical models including Tandon-Weng and Halpin-Tsai. These comparisons allow for the identification of deviations from the behavior expected of conventional blends and composites, highlighting the effects of nanostructuration and the presence of the organic modifier on materials behavior. (C) 2011 Elsevier Ltd. All rights reserved.