Multilayer two-dimensional lignin/ZnO composites with excellent anti-UV aging properties for polymer films

Lignin is a kind of natural green polymer with abundant active functional groups and designable molecular structure.In this work,the quaternized lignosulfonate(QLS)with amphoteric characteristic was prepared through chemical modification using lignosulfonate sodium(LS).Then,a lignin-confined multilayered two-dimensional composite(QLS/ZnO)was prepared by one-step dynamic hydrothermal method using QLS,zinc nitrate,and hexamethylenetetramine.The QLS/ZnO has a regular pie-shaped structure,which is composed of 3-5 layers of two-dimensional nanosheets with a thickness of~10 nm.It shows excellent ultraviolet light absorption performance and active photoelectron scavenging performance,and thus showing great application potential in polymer materials.The water polyurethane(WPU)and polyvinyl alcohol(PVA)films showed excellent UV shielding performance and good mechanical properties when doped with the QLS/ZnO.The tensile strength of WPU t 0.6 wt%QLS/ZnO and PVA t 0.8 wt%QLS/ZnO composite films is increased by 49%and 24%,respectively,and the elongation at break is increased by 138%and 33%.Furthermore,the composite films showed excellent anti-UV aging resistance after being aged under strong UV irradiation for 14 days.This work is of great significance to the high-value application of industrial lignin in the field of nano-functional materials.