Strong, water-repellent, and recyclable gelatin-based bioplastic film as sustainable express packaging film

With the increasing demand for express, serious environmental issues have been caused by the excessive waste express packaging plastic films. In this study, we report a facile approach to fabricate recyclable gelatin-based bioplastic film as an express packaging film substitute with considerable mechanical strength and water repellency. Sodium lignosulphonate (LS), and sulfited fish oil (FOS) were introduced to the film to enhance the water repellency of the film. The Fe3+ ions were used to connect LS and FOS with the gelatin matrix and shield the unpaired charged groups (−SO3−) to improve the hydrophobicity of the film. The Fe3+ ions can also improve the mechanical strength and stability of the film through forming metal–ligand bonds between all the components. Thus, the fabricated film exhibited high mechanical strength. After being washed under water flow for 30 s, the film still maintains good mechanical strength which is comparable with some traditional low-density polyethylene. After use, the film can be completely recycling or biodegradation. Additionally, the exceptional water repellency and UV-blocking capacity of the film makes it effective protection for goods at unexpected water encounter or long time UV exposure. Thus, this facile approach provided a sustainable option for green express packaging film.