Preparation and characterization of chitosan/α-zirconium phosphate nanocomposite films

Nano-fillers play an important role in the final structure and properties of nanocomposites. The objective of the work presented here was to prepare nanocomposite films of chitosan/alpha-zirconium phosphate using a casting process, with alpha-zirconium phosphate (alpha-ZrP) as nano-filler and chitosan as matrix. The effects of alpha-ZrP on the structure and properties of the nanocomposites were investigated. X-ray diffraction patterns showed that alpha-ZrP crystals were intercalated by n-butylamine. The results from scanning electron microscopy and transmission electron microscopy indicated that alpha-ZrP could be uniformly dispersed in the chitosan matrix when alpha-ZrP loading in the composites was less than 2 wt%. A strong interaction between alpha-ZrP and chitosan formed during the film-forming process. Tensile testing showed that the tensile strength and elongation at break of nanocomposite films achieved maximum values of 61.6 MPa and 58.1%, respectively, when alpha-ZrP loading was 2 wt%. The parameter B calculated from tensile yield stress according to the Pukanszky model was used to estimate the interfacial interaction between the chitosan matrix and alpha-ZrP. Films with a loading of 2 wt% alpha-ZrP had the highest B value (3.2), indicating the strongest interfacial interaction. The moisture uptake of the nanocomposites was reduced with addition of alpha-ZrP. It can be concluded that alpha-ZrP as nano-filler in a chitosan matrix can enhance the mechanical properties of nanocomposites due to the strong interactions between alpha-ZrP and chitosan. (C) 2010 Society of Chemical Industry