Polarization and relaxation mechanisms in glass fiber-reinforced LED-cured polyester composites incorporating graphene nanotubes

Abstract

The current research aimed to understand how the polarization and relaxation mechanisms in light-emitting diode (LED) cured glass fiber reinforced polyester (GFRP) composites change with graphene nanotubes (GNTs). In this context, the complex permittivity (ԑ*), loss tangent (tanδ), AC electrical conductivity (σ), and complex modulus (M*) features of the samples were measured via impedance spectroscopy. According to the virtual electrical modulus values, electrical polarization occurred after the first peak at 127 kHz. With increasing GNT ratio, a polarization mechanism was obtained at approximately 350 kHz as a result of a shift towards higher frequencies. Although a significant change was observed in the electrical conductivity value as the frequency increased depending on the GNT ratio, there was no change in the conductivity values up to 10 kHz. At high frequencies, dipole formation and orientation occurred, resulting in an increase in conductivity up to 150 kHz.