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Dielectric relaxation of conductive carbon black reinforced ethylene‐octene copolymer vulcanizates
Author(s) -
Das Suchilipsa,
Achary P. Ganga Raju,
Nayak Nimai C.,
Choudhary R.N.P.
Publication year - 2016
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.23186
Subject(s) - materials science , composite material , carbon black , dielectric , dielectric loss , dissipation factor , activation energy , permittivity , relaxation (psychology) , conductivity , natural rubber , psychology , social psychology , chemistry , optoelectronics , organic chemistry
The dielectric relaxation behavior of different conducting carbon black‐filled ethylene‐octene copolymer (EOC) vulcanizates prepared by melt‐mixing method has been studied as a function of frequency (100 Hz–5 MHz) over a wide range of temperatures (25–100°C). The effect of filler loading and frequency on AC conductivity, dielectric permittivity, impedance, and dielectric loss tangent (tanδ) has been studied. The nature of variation of the dielectric permittivity with the filler loadings was explained on the basis of interfacial polarization of the filler in the polymer matrix. The effect of filler loading on the real and complex part of the impedance was explained by the relaxation dynamics of the polymer chains in the vicinity of the fillers. The effect of filler and temperature on dielectric loss tangent, dielectric permittivity, AC conductivity, and Nyquist plot was also reported. The bound rubber (BR) value increases with increase in filler loading suggesting the formation of strong interphase, which is correlated with dielectric loss. Thermal activation energy ( E a ) was found to be decreasing with the temperature, which follows the Arrhenius relation: τ b = τ 0 exp(− E a / K B T ) where τ b is the relaxation time for the bulk material. From the plot of ln τ b versus inverse of absolute temperature (1/ T ), the activation energies ( E a ) were found to be 0.37 and 0.44eV, respectively. The percolation threshold was observed with 40 phr carbon black loading. POLYM. COMPOS., 37:342–352, 2016. © 2014 Society of Plastics Engineers