Improving the Compatibility of Zein/Poly(vinyl alcohol) Blends by Gamma Irradiation and Graft Copolymerization of Acrylic Acid

The effect of gamma irradiation and graft copolymerization with different ratios of acrylic acid monomer (AAc) on improving the compatibility of polymeric blends based on zein, as natural protein, and different ratios of poly(vinyl alcohol) (PVA) up to 50% were studied. The structure property of the polymeric blends was characterized by Fourier transform infrared spectroscopy (FTIR), mechanical testing, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The FTIR analysis indicated that grafted AAc into zein/PVA matrix was stabilized by hydrogen bonding. The stress strain curves showed that pure zein films were brittle, whereas pure PVA and zein/PVA blends films were tough materials either before or after gamma irradiation. The SEM micrographs indicated the formation of multilayers during the blending of zein and PVA, and these layers turned to dispersion in matrix after gamma irradiation and grafting with AAc, suggesting an effectiveness of gamma irradiation on improving compatibility.