The Development of Biodegradable PBAT-Lignin-Tannic Acid Composite Film: Properties, Biodegradability, and Potential Barrier Application in Food Packaging

Poly (butylene adipate-co-terephthalate) (PBAT), a biodegradable polymer, is a promising material in the food packaging industry. Its high elongation at break, ease of processibility, and biodegradability make it a substitute for low-density polyethylene. But its use in food packaging is limited to its cost, low tensile strength, and barrier properties. Herein, using a green approach, we prepared PBAT composite film with epoxidized soya bean oil (ESO) and encapsulated lignin (Lig)/tannic acid (Ta) (ESO-Lig-Ta) as filler. Different amounts (1, 2, 3%) of ESO-Lig-Ta were added to the composite film, and the effect on the properties was studied. The result showed that the ESO-Lig-Ta improved the tensile strength by more than 100%, and scanning electron microscopy (SEM) revealed a homogenous dispersion of the encapsulated filler in the matrix. The ultraviolet (UV) transmission decreased with an increasing amount of ESO-Lig-Ta. There was a reduced water vapor and oxygen transmission rate due to ESO-Lig-Ta than the neat PBAT film. Food (fresh potato and onion) sealed with the composite film remained fresh for up to 12 days at room temperature. The biodegradation of the composite film resulted from hydrolysis C-O/C = O, as shown by attenuated total reflection–Fourier transform infrared spectra (ATR-FTIR). The composite film can be extensively applied in short-lived fresh food packaging and long-term preservation and packaging of dry food products. Graphical Abstract ESO-encapsulated lignin and tannic acid incorporated into PBAT film as a potential food packaging film for short-live fresh products and long-term storage of dry food products.