Biomimetic soy protein-based exterior-use films with excellent UV-blocking performance from catechol derivative Acacia mangium tannin

Polymer plastic is the main component of current outdoor packaging film materials that are mostly derived from fossil fuels. Its poor ultraviolet (UV) barrier performance and short service life caused by aging degradation result in increased non-renewable consumption and environmental pollution. The most effective way to solve these problems is the development of a biomass-based and eco-friendly packaging with excellent UV-blocking performance. Herein, inspired by mussels, a facile strategy is reported for the preparation of a biomimetic polymeric material via the incorporation of a biomass-derived catechol derivative Acacia mangium tannin (AMT) into a biodegradable soy protein isolate (SPI) matrix. The morphologies, mechanical, thermal properties, and UV-blocking abilities and mechanisms of the modified films were evaluated. With the increase of the AMT content, the stress of the composite film was found to gradually increase, and the modified SPI composite film exhibited a powerful tensile strength of 7.64 MPa and a high breaking strain of 145.6%. After the introduction of AMT, the films exhibited excellent UV-blocking performance. As both SPI and AMT are biodegradable, this work presents an innovative design strategy for fully-biodegradable and robust polymeric materials with excellent UV-blocking performance that have promising potential applications in packaging.