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γ-Irradiation Effect on the Non-Cross-Linked and Cross-Linked Polyvinyl Alcohol Films

The non-cross-linked and cross-linked polyvinyl alcohol (PVA) films were prepared by the casting method then irradiated with gamma rays for various doses up to 300 kGy. The structure and characterization of PVA were determined by using Infrared spectroscopy (FTIR), ultraviolet spectroscopy (UV) and X-ray diffraction (XRD). Swelling behaviour was also investigated. Mechanical properties have been examined with respect to the absorbed dose. The color of the films changed to yellowish-white after irradiation and the crystallinity of the films decreased with increasing dose. Additional changes observed by FTIR analysis of the degradation products demonstrated that the radiolysis of PVA was initiated by liberation of H and OH groups leading to scission of the main chains and formation of carbonyl and double bond groups. Thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were performed. The FTIR, UV, XRD and mechanical properties indicate that the addition of cross-linker led to high degrees of interaction between the cross-linker and the macromolecules of polymeric chains and acted as a stabilizing agent against gamma irradiation.