Deformation and failure studies of polymer nanocomposites

Addition of small percentage of nanoparticles to polymers significantly improves many of their mechanical, physical and transport properties. However, embrittlement of polymer nanocomposites (in particular, when reinforced with nanoclay layers) is a critical issue that has curtailed potential applications of this class of new materials. Several aspects surrounding embrittlement and efforts that have been used to understand some facets of this issue are discussed, with special emphasis on our own recent and current research findings. Questions which will be addressed include: (a) toughening mechanisms and the "mobility concept"; (b) sequential blending on microstructures and toughening; (c) nano-void toughening; and (d) deformation and failure subjected to cyclic fatigue on typical binary and ternary nanocomposites. Accurate interpretations and understanding of the origins of these complex questions require the precise knowledge of both surface and sub-surface phenomena at different scales. A range of microscopic techniques and analytical tools are used to unveil the processing-structure-property relationships of these nanocomposite materials.