Effect of pre-axial tensile tension, temperature, and hysteresis loss of natural rubber doped MWCNTs on the electrical properties for sensors applications

Abstract

In view of its large application, one used natural rubber (NR). The effects of MWCNTs contents on electrical properties as well as the effect of both pre extension and mechanical hysteresis on the electrical properties of these composites were discussed. At low MWCNTs contents (≤6 phr), έ, σac, and σdc showed to have slight changes. Meanwhile, contents (≥9 phr) have significant increase as a result of its interfacial polarization. That is, the composite became conductive. Higher positive electrical conductivity coefficient (PTCC) intensity was detected for the 3phr sample. The effect of the electric field on the mechanical creep characteristics and its corresponding parameters were investigated. Conventional elastic modulus was found to increase with both MWCNTs concentration and the applied stress in all samples about six times its original value. Current creep curves were constructed and maximum piezoresistivity was found for sample 3phr with a negative effect on piezoresistivity, which can be employed as a pressure or force sensor. The parameters deduced from hysteresis loop such as the strain coefficient of conductivity, damage parameter, strain energy density, inelastic strain, elastic strain, and mismatch parameter are strongly dependent on both the MWCNTs concentration and the applied mechanical stress. The damage parameter increased to about 20 times with increasing the concentration, while the decreases with increasing number of hysteresis cycles. The activation energy decreased with the pre-axial tension, while no effect of electrical conductivity.