Study on the Effect of Lignin Removal Rate on the Dielectric Properties of Delignified Materials

Abstract

To investigate the relationship between the lignin removal rate change of wood and its dielectric properties, this study employed Mongolian Scotch Pine and Paulownia as the test materials. The acidic sodium chlorite method was used to delignify the treated material, and the lignin removal rate was determined at a specified reaction time interval to ascertain the dielectric constant and the tangent of the dielectric loss angle. The findings revealed that: As the delignification process progresses, the lignin content declines, accompanied by a reduction in the dielectric constant at elevated frequencies. This decline reaches a plateau near 10 MHz. The results demonstrated that the dielectric constant of the samples decreased with an increase in frequency and exhibited a stabilizing effect near 10 MHz. However, the dielectric constant of delignified wood was significantly higher than that of untreated wood. Additionally, the dielectric constant exhibited a linear relationship with the increase in lignin removal rate, while the tangent of the dielectric loss angle demonstrated a tendency to increase and then decrease. An investigation into the dielectric properties of delignified wood can yield valuable data and a theoretical foundation for the development of wood-based dielectric materials.