High Strength UV-Resistant Composite Film of Fe³⁺-Coordination Lignin/PVA

The literature on polyvinyl alcohol (PVA) films is extensive, however, these methods often necessitate intricate synthesis processes or the addition of plasticizers to modify the strength and water solubility of the PVA material. A high-strength UV radiation-resistant composite film by chelating Fe³⁺ with lignin and PVA, which exhibits excellent hydrolysis resistance is developed. This composite film is prepared simply by incorporating a small amount of dealkalized lignin (APPL) and ferric chloride (FeCl₃) into PVA through a straightforward composite process. During the scanning test, it is noted that the film exhibits a high density of uniformly dispersed particles, endowing it with efficient ultraviolet absorption capabilities. The infrared and anti-dissolution tests reveal that the coordination of Fe³⁺ with lignin imparts an outstanding hydrolysis resistance to the film, obviating the need for any extender, curing agent, acid or base. The tensile fracture strength reaches an impressive 187.81Mpa in the tensile test. UV and indicator card tests unequivocally demonstrate that the film achieves a remarkable 100% anti-UV efficiency. This Fe³⁺ chelated lignin/PVA composite film, with its facile preparation, environmental sustainability, high strength, and outstanding anti-ultraviolet efficiency, can be deployed across diverse applications requiring robust protection against ultraviolet radiation.