Structural and Dielectric Properties of Pristine Bentonite-PVC Nanocomposites

In this study, the structural and dielectric properties of pristine bentonite-PVC (Polyvinyl chloride) nanocomposites were systematically investigated. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses confirmed the partial intercalation of PVC molecules between the bentonite layers and their interaction with surface hydroxyl groups. The dielectric properties of the nanocomposites were examined via impedance spectroscopy over a broad frequency range of 1 Hz–10 MHz. The results revealed that PVC loading significantly influenced dielectric permittivity, dielectric loss, and loss tangent (tan δ). At low frequencies (<1 kHz), the permittivity and dielectric loss values of 25 mg, 35 mg, and 100 mg PVC-loaded nanocomposites were notably higher compared to pristine bentonite, indicating enhanced interfacial polarization. The relaxation frequency of pristine bentonite was determined to be 39 kHz, which shifted to lower frequencies upon polymer loading due to intercalation and surface interactions. Notably, in the 35 mg PVC-loaded nanocomposite, the relaxation frequency decreased to 12 kHz, suggesting stronger polymer-clay interactions. In addition, AC conductivity (σac) analyses were performed and successfully fitted with the Jonscher power law, confirming the dominant role of interfacial polarization and dipolar confinement on charge transport behavior. These findings demonstrate that the dielectric behavior of PVC-bentonite nanocomposites is governed by both intercalation and surface interactions, which modulate charge carrier mobility and polarization mechanisms. The integration of structural (XRD, FTIR) and dielectric (impedance spectroscopy) analyses provides a comprehensive understanding of the impact of polymer loading on the dielectric performance of bentonite-based nanocomposites.