Terahertz dielectric spectroscopy of natural vulcanized rubber by thermal oxidation

The aging of natural rubber products is a common phenomenon in its use, and the essence of aging is that the material itself is flawed and easily affected by external factors. Dielectric spectrum is a macroscopic manifestation of micro-polarization which is the dependence of dielectric constant on electromagnetic frequency or temperature. According to the plastic/rubber hot air aging standard GB/T3512-2014, the thermal oxygen experiment of natural vulcanized rubber was carried out in the experimental chamber of 100℃ for more than 1 000 hours, and the relationship between the dielectric spectrum of samples and aging time was studied. By tracking test, the effective data of complex permittivity and loss tangent value of 0.2-1.2 THz rubber were obtained every 24 hours. Based on the complex permittivity values, the polarization characteristics of the deduced rubber and the statistical microcosmic movement types can be calculated, and the molecular structure changes of the natural vulcanizates characterized by terahertz dielectric spectrum were analyzed. Due to the similarity of the aging of the material, the results can also play a positive role in studying other polymer materials aging.