Blend films from sodium alginate and gelatin solutions

Blend films were prepared by blending 4 wt% sodium alginate and 5 wt% gelat in aqueous solutions and dried at room temperature for 2 days to obtain the transparent films. Their structures and properties were studied by infrare d (IR) spectra, wide-angle X-ray diffraction (WAXD), scanning electron micr oscopy (SEM), thermogravimetric analysis (TGA), and differential thermal an alysis (DTA). Significant changes in the shape and intensity of IR spectra absorption frequencies characteristic of either gelatin or sodium alginate were detected by IR analysis. The crystallinities of the blend films decrea sed with the increase of sodium alginate content. The thermal stability, me chanical properties of tensile strength, and breaking elongation of the ble nd films were improved by blending sodium alginate with gelatin. It is wort h noting that the breaking elongation reached 16.6% when the weight ratio o f sodium alginate to gelatin was 1:1, much higher than that of two componen ts. The structure analysis indicated that there is strong interaction betwe en sodium alginate and gelatin molecules resulted from intermolecular hydro gen bonds and ionic interactions. The water absorbability of the blend film s was improved due to the introduction of sodium alginate.