Fabrication and Characterization of Lignin Particles and Their Ultraviolet Protection Ability in PVA Composite Film

Recently, lignin utilization in advanced applications has gained much interest. Due to the limitation of the current use of standard lignin, lignin particles have recently gained attention in overcoming the challenge. In this work, the spherical lignin particles obtained from organosolv lignin (OL) were prepared using the dialysis method with tetrahydrofuran (THF) or ethanol as the solvent. From the result, it was found that the types of lignin and solvent, initial lignin concentration, and stirring rate strongly affected the size of fabricated particles. Moreover, the preparation of lignin particles using THF as a solvent showed more uniform and symmetric spherical lignin particles. The stability of the particle dispersion was examined under various pH conditions. Moreover, lignin samples were also introduced into the poly­(vinyl alcohol) (PVA) for the production of ultraviolet (UV)-blocking composite film. Mechanical and optical properties of composite film were also observed. As a result, the prepared lignin–PVA composite film showed great ultraviolet (UV) protective potential in both UVA and UVB regions.