Intermolecular interactions in blends of hyaluronic acid with poly(vinyl alcohol) and ethylene-vinyl alcohol copolymers

Abstract

Films from blends of hyaluronic acid with poly(vinyl alcohol) and with ethylene-vinyl alcohol copolymers were prepared from solutions in water and dimethylsulfoxide by a casting method. The study of the interactions between the natural and synthetic component has been carried out through thermal and morphological analysis. The results show that the crystallinity of poly(vinyl alcohol) and its copolymers decreases with increasing hyaluronic acid content and these crystallizable polymers exhibit no tendency to crystallize when hyaluronic acid content is more than 80 wt%. The relatively good miscibility in these blends may be due to the capacity of the natural and synthetic component, each with abundant hydroxyl groups, to interact mutually through hydrogen bonding. The presence of such interactions was supported by the observation of the melting point depression of the synthetic component in thermal analysis of the blends. Melting point depression was more accentuated in melt recrystallized blends. These results suggest that the interactions between the two polymers are enhanced if the blends are brought close to the melting point of the synthetic component.