Photo-crosslinked gelatin�polyvinyl alcohol composite films: UV�riboflavin treatment for improving functional properties

In this study, physicochemical and structural properties of films based on gelatin (G), polyvinyl alcohol (PVA), and composite films (0PVA:1G, 1PVA:2G, 1PVA:1G, 2PVA:1G, 1PVA:0G) using photo-oxidation (in the presence of sensitizer riboflavin) were investigated. UV barrier of the UV-treated films was significantly improved as the light transmission at a wavelength of 200�350 nm was obtained from 0 to 0.7. The photosensitizer-induced cross-linking significantly decreased water vapor permeability and solubility of the films. The results demonstrated that the mechanical properties of UV-treated films were significantly improved compared to the control sample. The tensile strength (TS) improved by increasing the gelatin content in composite films where the 1PVA:2G treatment showed the highest TS (61.13 MPa). SEM images also showed a dense and homogenous tissue in 1PVA:2G compared to the other composite films. According to DSC and FTIR results, the most efficient interactions were established for 1PVA:2G composite film. The obtained results showed the effectiveness of the photo-oxidation process in improving films� properties encouraging the use of this method in the production of biodegradable films. Practical applications: In this study, according to the experiments, the photo-oxidation process with riboflavin as a sensitizer can increase the physicochemical properties of the biodegradable films by increasing the interaction between the ingredients even better than typical nylon films such as heat resistance, tensile strength, mechanical properties, and lack of UV and moisture permeability. This production technique can be tested in the industry to produce packaging with better properties. © 2020 Wiley Periodicals LLC