Electrical conductivity degradation of fatigued carbon black reinforced natural rubber composites: Effects of carbon nanotubes and strain amplitudes

Abstract

The fatigue of rubber products is usually accompanied by undesirable transformation in their properties. The present work was dedicated to the investigation of consequences of fatigue loading on volume electric conductivity of natural rubber (NR) reinforced with 30 phr of fillers composed from various weight combinations of carbon nanotubes (CNTs) and carbon black (CB). Special attention was paid to study the influence of CNTs content on residual electric conductivity and a possible mechanism of fatigue driven rearrangement of hybrid filler network inside of rubber matrix was propounded forward. An increase in the CNTs content over the complete range of concentrations, enhanced the conductivity of fabricated samples up to two orders of magnitude in comparison to rubber compounds without CNTs. All the samples were subjected to harmonic sinusoidal loading at a frequency of 5 Hz up to 10(5) loading cycles at three different strains of 0.1, 0.25 and 0.5. Despite very little transformation in the polymer matrix, fatigue caused a progressive degradation of conductivity with an increase in applied strain. It was also found that with the addition and a subsequent increase in the concentration of CNTs, the undesirable reduction of conductivity was significantly arrested. This novel finding added another number to the list of the outstanding properties of CNTs.