An effect of deacetylation of chitin on the miscibility of chitin/poly(vinyl alcohol) blends

Abstract

The transition behavior and miscibility state of chitin/poly(vinyl alcohol) (PVA) blends were investigated by DSC and dynamic mechanical analysis. In order to examine the effect of the deacetylation of chitin on its miscibility with PVA, chitin materials having different degrees of deacetylation (DD) were prepared from homogeneous alkaline solutions. Blend films of the deacetylated chitins with PVA were obtained successfully from mixed polymer solutions in aqueous acetic acid or in dimethylacetamide-lithium chloride. For samples prepared so that the DD of the chitin component was in the range of 40∼60%, a composition-dependent shift in the Tg of PVA and a systematic depression in the melting temperature of this component were observed clearly, while for the other samples of DD < 40% or DD >60%, the shift in the transition temperatures was less prominent. Thus the use of the restricted chitins of 40∼60% DD was found to result in an especially good miscibility state in the amorphous regions of the blends with PVA.