Facile design of tough, strong, and UV-shielding soy protein-based composite films

Designing soy protein (SP)-based composite films with great toughness and high strength remains an intractable challenge. In this work, a facile strategy for preparing SP-based composite films by incorporating polyethyleneimine (PEI) as plasticizer and lignin-Ag nanoparticles (NPs) as green reinforcer is proposed. The fabricated films exhibit great toughness of 15.22 MJ m −3 , high tensile strength of 10.44 MPa, which are 375.6 % and 493.2 % increase compared with that of the neat glycerol-toughened SP film. The films also perform a high strain at failure of 188.48 %. In addition, the developed composite films have good biodegradability and excellent UV-shielding performance, which can block 100 % of the UV spectrum. This work offers a novel method for fabricating SP-based films with great toughness, ductility, and strength for many potential applications, such as packaging engineering and UV-blocking areas.