An overview of the progress in polymer nanocomposites is presented in this paper with an emphasis on the different methods used for preparing polymer-layered silicate (PLS) nanocomposites and the extent to which properties are enhanced. Other related areas that are also discussed include the types of polymers used in PLS nanocomposites preparation, the types of PLS nanocomposites morphologies that are most commonly achieved, the structure and properties of layered silicates, and the most common techniques used for characterizing these nanocomposites. C 2007 Wiley Periodicals, Inc. Adv Polym

The morphology of blends of polycarbonate and nylon 6,6 with a copolyester of 60 mole percent p‐hydroxybenzoic acid/40 mole percent poly(ethylene terephthalate) was characterized under different processing conditions. In particular, single‐screw extrusion, steady simple shear flow, and flow through a capillary were studied to determine what conditions were necessary for the development of a fibrillar morphology of the liquid crystalline polymer (LCP). Results indicate that some extensional flow is required for the coalescence and extension of the particulate LCP phase. The viscosity of the blends was determined both in a cone‐and‐plate geometry of a Rheometrics Mechanical Spectrometer at low shear rates and in the Instron Capillary Rheometer at higher rates. In general, only a small (10 or 30 percent) weight fraction of LCP was required to reduce the viscosity of the thermoplastics to that of the polymeric liquid crystal. An attempt was made to correlate the structure of the blends seen under the scanning electron microscope with the observed rheology. Not all aspects of the morphology were possible to explain in terms of the viscous properties of the blends.

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