DSC studies on bound water in silk fibroin/S-carboxymethyl kerateine blendfilms

The physical state of water, absorbed in silk fibroin (SF)/S-carboxymethyl kerateine (SCMK) blend films, was studied by differential scanning calorime try (DSC) to investigate the change of internal structures of the blend fil ms. The amount of non-freezing bound water in the blend film was decreased with the addition of SCMK because of the change in the secondary structure of SF from random coil form to beta-structure form. This transition could b e also monitored by thermal analysis using DSC. The maximum change of the s econdary structure was observed at a blend ratio of 50/50 (wt/wt). (C) 1999 Elsevier Science Ltd. All rights reserved.