A novel method to prepare chitosan/montmorillonite nanocomposites

We are proposing a novel method to prepare chitosan/montmorillonite nanocomposites. The montmorillonite (MMT) clay was excavated from the mountainside of eastern Taiwan. After being purified, it was incorporated with potassium persulfate (KPS) through the intercalation process. As the KPS-incorporated MMT was dispersed in the acidified aqueous solution of chitosan, the KPS instantly reacted with the chitosan, resulting in the cleavage of polymer chains and exfoliation of MMT as well. After removing the unexfoliated MMT, solutions were cast to form a film of chitosan/MMT nanocomposite. Interestingly, the exfoliated MMT layers were found to flatten out in parallel with the surface, which not only increased the tensile strength of the chitosan film but also hindered degradation in the vitro test. (c) 2005 Wiley Periodicals, Inc.