Preparation and physical properties of blend films from sodium alginate and polyacrylamide solutions

Blend films of sodium alginate and polyacrylamide (PAAm) were prepared by mixing the aqueous solution of both samples at a different ratio. All blend films obtained are optically clear to the naked eye. The structure and physical properties of the films were studied by FT-infrared (FT-IR), wide angle X-ray diffraction (WAXD), differential thermal analysis (DTA), thermogravimetic analysis (TGA), scanning electron microscopy (SEM), and tensile strength test. The results showed that the occurrence of interactions between -COO-, -OH groups of sodium alginate and -CONH2 groups of PAAm in the blends through hydrogen formation. The blend films exhibited the higher thermal stability and improved mechanical properties in dry states. These properties had the maximum value around 20 wt% PAAm content in the blend film. The morphological transition of the blend films from sodium alginate-like to PAAm-like was observed by scanning electron microscopy.