Thermal and Optical Properties of Gelatin/Poly(vinyl alcohol) Blends

Differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, and ultraviolet visible spectroscopy of gelatin and poly(vinyl alcohol) (PVA) homopolymers and their blended samples were studied. The data revealed that the gelatin and PVA polymers were compatible over the investigated range of compositions; this contributed to the formation of hydrogen-bonding interaction between their polar groups. The associated enthalpy-of-melting transition and thermal stability of the blended samples increased with increasing PVA content. This indicated that the crystalline structure of PVA was not destroyed completely in the blends, which was consistent with the X-ray diffraction pattern of the 50/50 (wt %/wt %) blended gelatin/PVA sample. The absorption edge and optical band gap for allowed direct transition were determined from ultraviolet visible spectra. The induced changes in the band structure are elucidated. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 413-420, 2010