Intercalated Polypropylene Nanocomposites

Abstract

Polypropylene (PP) is a versatile material whose use has significantly penetrated numerous sectors of the manufacturing, medical, and packaging industries. Polymer clay nanocomposites are multiphase organic/inorganic hybrid materials pioneered by researchers at Toyota, which may exhibit significantly improved mechanical, flammability, and permeability properties relative to the base polymer matrix at very low clay loading. Although first demonstrated for nylon, polymer clay nanocomposites have since been prepared for a range of thermoplastic and thermoset polymers. However, the development of PP clay nanocomposites poses special challenges because of polypropylene’s hydrophobicity. Nevertheless, possible commercial applications have motivated substantial research into strategies for the dispersion of clays in this technologically important polymer. This article reviews recent progress in the synthesis, preparation, and characterization of polypropylene nanocomposites. The resulting clay intercalation structure receives particular attention because most polypropylene nanocomposites prepared to date have yielded significant structures of this kind. After reviewing the state-of-the-art in polypropylene nanocomposite synthesis, characterization of clay and polymer morphology, and measurement of rheological and mechanical properties, we identify future research challenges that should be addressed to continue improving the possibility for commercial applications of these materials.