Thermal analysis of chitosan and its blends

The present work is concerned with experimental results of DMTA and DSC techniques, which are used to study phase relaxation behavior of chitosan having various DD and its blends with polyvinyl alcohol (PVAL) and hydroxypropylcellulose (HPC). The analysis of DMTA spectra of chitosan leads to recognition of a few molecular relaxations in chitosan and in its blends. A strong effect of water presence on the macromolecular dynamics is observed. Double wet relaxations (close to ambient temperature) are observed. Optical film transparency of the chitosan blends with PVAL and HPC allows us to predict good miscibiliry of components in the complex systems. However, unchanged temperatures of the glass transitions of PVAL and isotropization of HPC in the blends indicate separation of components. However, a low content of PVAL or HPC can be molecularly distributed in a chitosan matrix giving a miscible system of good mechanical properties. (C) 2004 Elsevier B.V. All rights reserved.