Study of the effect of surface oxidation treatment on the dielectric properties of delignified material

To investigate the relationship between the degree of surface oxidation of delignification materials and their dielectric properties, sodium periodate was used to oxidize the delignification samples of Pinus sylvestris var. Mongolia and Paulownia fortunei (Seem.) Hemsl. The degree of oxidation was reflected by the degree of substitution of aldehyde and carboxyl groups at a specific reaction time interval, and then the dielectric constant and dielectric loss tangent were measured. The results show that with the increase of oxidation time, the crystallinity decreases and the hydrogen bond network is weakened. In the frequency range of 103–107 Hz, the dielectric constant of the sample decreases with the increase of frequency and tends to be stable near 10 MHz, but the dielectric constant of the oxide material is significantly higher than that of the untreated material. At the same time, the dielectric constant increases with the increase of oxidation time, while the dielectric loss tangent decreases.