Terahertz spectroscopy studies on dielectric and thermal stability properties of polymer resins

Polymer resins have been widely used as 5G communication materials due to their excellent dielectric and thermal properties. Recently, three bio-based polymer resins have been synthesized, and their excellent mechanical properties and low dielectric performances at a low-frequency band from 0.1 to 10 7 Hz have been verified [ Compos. Part B 284 , 111728 ( 2024 ) 10.1016/j.compositesb.2024.111728 ]. However, their dielectric and thermal stability properties at 5G, 6G, or higher-terahertz (THz)-frequency bands have not been investigated. In this work, THz spectroscopy measurements of three polymer resins are performed at room temperature and temperatures varying from 30° to 300°C at a heating rate of 5°C/min, and the absorption coefficient, dielectric constant, and dielectric loss tangent of these polymer resins are determined at the frequency band from 0.5 to 3.5 THz. Results indicate that all three polymer resins have a low dielectric constant less than 2.63 and a low dielectric loss less than 0.056 at 1.0 THz at room temperature, and the fluctuations of their dielectric constants and dielectric losses with temperature are both less than 10%, which are well comparable to the performances of the popular 5G material of polyphenylene ether (PEEK), indicating they have excellent low dielectric and thermal stability properties at the THz frequency band and are suitable for using as 5G, 6G, or higher-frequency-band communication materials.