Investigation of Relaxation Process of Polycarbonate/poly(vinylidene fluoride-hexafluoropropylene) Composites Using Dielectric Relaxation Spectroscopy

Abstract

Dielectric and conductivity relaxation behaviors of Poly (vinylidene fluoride-hexafluoropropylene) [P(VDF-HFP)] and its composites are investigated on the basis of dielectric relaxation spectroscopy at 20 to 200°C and 20–5 M Hz. We have observed that imaginary modulus spectra exhibit asymmetry peak with peak-width much broader than that of the debye peak. The peaks are skewed toward the high frequency sides due to conductivity. Treating the imaginary parts of complex modulus spectra with Kohlrausch-Williams-Watts (KWW) and Havriliak-Negami (HN) equations, it is found that the obtained low shape parameters (α, γ) and non-exponential parameter (β) gradually decreases with PC composition increasing, indicating that a wide distribution of relaxation times which belong to non-Debye-type relaxation process. The both activation energies (Eτ and Eσ), which are attributed to contributions of multiple relaxation processes, are very close at corresponding sample. But, Eτ and Eσ gradually increase with PC composition increasing.

Structural, impedance, and modulus spectroscopic studies on Y2/3Cu3Ti3.95In0.05O12polycrystalline material prepared by flame synthesis method

“…With comparison of Z"/Z" max , it indicates that the short-range or long-range movement of charge carries are the dominant contributors of dielectric relaxation. As reported earlier, the different peak frequencies for M and Z indicate that the relaxation process is dominated by the short-range movement of charge carriers and deviated from an ideal Debye-type behavior (37,38).…”