Physically crosslinked polyvinyl alcohol–dextran blend xerogels: Morphology and thermal behavior

Physically crosslinked hydrogels composed of different amounts of dextran in PVA matrix were prepared by applying freeze–thaw cycles to their aqueous solutions. Morphology, thermal properties and FTIR spectra of the resulting blend xerogels were examined by SEM, DSC, TGA and FTIR spectroscopy. Blend xerogels containing 10% (w/w) dextran showed more compatibility/miscibility according to SEM and DSC results. The Tg of the xerogels did not show any significant changes with increased dextran content. Introducing dextran into the freeze–thawed PVA structure affected crystal size distribution of PVA; and hence thermal degradation behavior of the xerogels. An increase in dextran content resulted in broader crystal size distribution; better and still lower thermal stability in comparison to virgin PVA and freeze–thawed PVA, respectively.