AC and DC electrical conductivity in natural rubber/nanofibrillated cellulose nanocomposites

In the present study, charge transport properties of natural rubber based nanocomposites are investigated. Natural rubber is doped at various doping rates with nanofibrillated cellulose extracted from the rachis of date palm tree. The physical origin of both direct current (DC) and alternating current (AC) conductivity of polymer matrix-cellulose nanocomposites has been investigated. In fact, high activation energy values from DC measurements prove that the conductivity in the present samples is of an ionic nature. In addition, DC conductivity is more thermally activated than AC conductivity suggesting the random free-energy barrier model to explain the hopping conduction mechanism. Moreover, AC conductivity of these composites is frequency and temperature dependent, it generally follows the exponential law σAC ~ ωs. Exponent s lies in the range 0 < s < 1, characterizing an ionic hopping mechanism. Finally, using the Barton-Nakajima-Namikawa (BNN) relationship implies that the same ionic hopping mechanism is responsible for both AC and DC conduction.