Preparation of lignin/TiO2 nanocomposites and their application in aqueous polyurethane coatings

摘要

A simple method using a water soluble lignin quaternary ammonium salt (LQAS) and TiO2 has been developed for the preparation of lignin/TiO2 nanocomposites in an aqueous medium under mild conditions.The LQAS/TiO2 nanocomposites contain well-dispersed small particles with excellent ultraviolet (UV) shielding abilities and good compatibilities with waterborne polyurethane (WPU).When the LQAS/TiO2 nanocomposites were blended with WPU,the UV absorbance and the tensile ductility of the WPU increased significantly.The composite WPU hybrid film containing 6 wt-％ LQAS/TiO2 nanocomposite had the highest visible light transmittance and had excellent ultraviolet aging properties.After 192 h of UV light irradiation,the tensile strength of the composite film was above 8 MPa and the elongation at break was 800％.This work highlights new possibilities for the utilization of alkali lignin.