polyethylene oxide (PEO)/gelatin blend membranes of four different compositions (w/w) (5/95, 10/90, 20/80, and 30/70) were prepared by solution casting. The films were irradiated by gamma radiation at a total dose of 250 krad (dose rate of 321 krad/h). The X-ray diffractograms demonstrate both the PEO and radiation influences on the blend thus enhancing crystallinity of gelatin. X-ray diffractograms of irradiated blend films containing 30% PEO showed highest integrated intensity. The DTA and TGA study showed that the irradiated blend films are more thermally stable than the non-irradiated films. TMA study showed that the incorporation of PEO into gelatin increased melting point of the blend films. The melting point for irradiated gelatin film changes from 52.9 degrees C to 75.6 degrees C and the glass point changes from 60.3 degrees C to 90.6 degrees C. The phase separation and compatibility of the PEO/gelatin blend films were studied by scanning electron microscopy (SEM). The experimental results showed that the blend films exhibit higher thermal stability and improved mechanical properties in dry state, which suggests the occurrence of interaction detected by XRD and DTA among gelatin, PEO, and water molecules in the films. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 2075-2082, 2010