Electrical conductivity and electric modulus of stable Kevlar^® fiber loaded HAF/NBR rubber composite

Abstract

DC, AC conductivities and dielectric properties of high abrasion furnace carbon black (HAF)/acrylonitrile butadiene rubber (NBR) composite have been studied with varying the aramide Stable Kevlar V R fiber content, temperature, and frequency. Generally, the electrical conductivity was decreased with increasing Stable Kevlar V R fiber content, which was confirmed by the positron annihilation lifetime spectroscopy. Negative temperature coefficient of conductivity (NTCC) behavior between 353 and 413 K was detected, except for the composite containing 10 phr Kevlar which showed positive temperature coefficient of conductivity (PTCC) behavior above 383 K. These NTCC and PTCC behaviors were further manifested by differential scanning calorimetry (DSC). For the composite with 10 phr Kevlar, the interfacial polarization between the fibers and the polymeric composite can be ascribed to Maxwell-Wagner-Sillars mechanism. The (MWS) relaxation disappeared for higher fibers content. The analysis of the electric modulus in the frequency range from 1 kHz to 1 MHz shows that the interfacial relaxation obeys Cole-Davison distribution of relaxation times.

Promising naphthol green B dye doped (PVOH-PEG) composite films as a multifunctional material with engineered optical band gap, tunable dielectric properties and nonlinear J–E characteristics

“…While the decrease in  M at higher frequencies as a result of the confinement of charge carriers in their potential wells and their ability to undergo SR motion between the localized sites [80]. This behaviour agrees well that obtained by other researchers on polymer composites [77,79,81,82].…”

“…In high NGB concentrations (20 and 25 wt. (%)) the increase of charge carriers leads to an enhancement of MWS polarization and causes the observed shift of the relaxation peaks to lower frequency which can be confirmed by the calculated values of relaxation time t presented in the inset of figure 10(b) [77,79,82].…”

“…The complex electric modulus * M for (PVOH-PEG)/NGB films can be calculated using the complex permittivity e* as the following relation [77]: + be attributed to the conduction via short range (SR) charge carriers mobility [79]. The plot of  M versus logf shows a single broad relaxation peak at relaxation frequency f max corresponding to relaxation time…”

Preparation and Properties of Ethylene Propylene Diene Rubber/SiO₂/Carbon Nanotubes Composites

“…Because the EPDM has much low crystallinity, it need to be reinforced through various methods, such as addition of fillers in engineering usage. such as carbon black [1][2][3][4][5][6][7][8][9][10][11], silica [12], fibers [13] and other filler particles. [14,15] Silica with the special structure, represents an important mineral material for common filler and engineering fillers, which can improve the mechanical properties of polymer matrix to reach excellent interaction between polymer and filler [16].…”

Influence of blend ratio on the electrical characteristics of vulcanized SBR/NBR blends compatibilized by Cis-polybutadiene rubber

“…Many theoretical models were suggested for the AC conduction in amorphous semiconductors e.g. classical hopping and quantum mechanical tunneling of charge carriers through the potential barrier separating two energetically appropriate centers in a random distribution [15]. In electron tunneling model, is independent of .…”