Facile fabrication of transparent lignin sphere/PVA nanocomposite films with excellent UV-shielding and high strength performance

With the rapid development of human society, more and more concerns are directed to utilization of environment-friendly and biodegradable materials. To meet this demand, we fabricated an environment-friendly poly (vinyl alcohol) (PVA)/lignin nanocomposite films with excellent UV-shielding and visible-transparent performance. The lignin-based nanosphere (LNSs) were prepared via self-assembly and uniformly distributed in the PVA matrix by forming strong hydrogen bonds with PVA matrix. With the introduction of LNSs into PVA matrix, the various performance such as tensile strength, thermal stability, and UV-shielding of PVA/Lignin nanocomposite films were enhanced. Amazingly, the UV-shielding results revealed that UVB (320-275 nm) and UVC (275-200 nm) were completely shielded and UVA (400-320 nm) was mostly shielded with addition of 4 wt% LNSs. Meanwhile, the tensile strength of the nanocomposite film was dramatically enhanced, in which the strength increased from 76 MPa to 112 MPa. Since both lignin and PVA were biodegradable materials, this work provides a simple and valuable method for the preparation of biodegradable and functional films.