Development of a Program for Analyzing Dielectric Relaxation and Its Application to Polymers: Nitrile Butadiene Rubber

To characterize the dielectric relaxation embedded in polymers, we developed a program algorithm that analyzes the relaxation processes from dielectric permittivity versus frequency data based on governing functions such as the Havriliak-Negami function including the conductivity contribution. With the help of the developed simulation program, we have identified three processes: an α process due to rotational and segmental motions of the C-C bond, an α’ process attributed to the fluctuation of the end-to-end dipole vector of the polymer chain, and the conduction contribution observed at high temperatures and low frequencies. The activation energy and glass transition temperature for the two main relaxations were independently determined from both the imaginary permittivity versus frequency and temperature by assuming Arrhenius dependence and the Vogel-Fulcher-Tamman law. The results obtained by the two methods for α and α’ relaxations were compared with each other and with that obtained by differential scanning calorimetry.