Biopolymer chitosan/montmorillonite nanocomposites: Preparation and characterization

Biopolymer chitosan/montmorillonite nanocomposites have been prepared in which montmorillonite (MMT) is used as nanofiller and diluted acetic acid is used as solvent for dissolving and dispersing chitosan and montmorillonite. Morphology and properties of chitosan nanocomposites with and without acetic acid residue have been studied compared with those of pure chitosan. The effect of acetic acid residue and MMT loading in nanocomposites has been investigated. The XRD and TEM results indicate the formation of an intercalated-and-exfoliated nanostructure at low MMT content and an intercalated-and-flocculated nanostructure at high MMT content. The thermal stability and the mechanical properties of the nanocomposites are characterized by TGA and nanoindentation. The nano-dispersed clay improves the thermal stability and enhances the hardness and elastic modulus of the matrix systematically with the increase of clay loading. The existence of acetic acid residue in chitosan matrix will affect its crystallinity, thermal stability and mechanical properties. (c) 2005 Elsevier Ltd. All rights reserved.