AC Conductivity of Selectively Located Carbon Nanotubes in Poly(ε-caprolactone)/Polylactide Blend Nanocomposites

Abstract

DC and AC electrical conductivity of bionanocomposites based on the immiscible polymer blend poly(epsilon-caprolactone)/polylactide (PCL/PLA, w/w 70/30), loaded with multiwall carbon nanotubes (CNT), were studied in a wide frequency range, 10(-3) < or = f < or = 10(7) Hz from 143 to 313 K. The nanofiller concentration ranged from 0 to 4 wt % and it was shown to be selectively located in the PCL phase. The PCL crystallinity degree was not affected by the presence of CNT. The variation of the DC conductivity allowed the determination of the percolation threshold, p(c) = 0.98 wt %, and the critical exponent t = 2.2 of the scaling law. The linear dependence of log (sigma(DC)) versus p(-1/3) showed the existence of tunneling conduction among CNT not yet in physical contact. The temperature independent results indicated a conventional tunnel effect. The AC conductivity of the nanocomposites followed the predictions of the universal dynamic response and the s exponents were determined at low concentrations. Master curves are presented showing the length and temperature-time superpositions.

A strategy for achieving low percolation and high electrical conductivity in melt-blended polycarbonate (PC)/multiwall carbon nanotube (MWCNT) nanocomposites: Electrical and thermo-mechanical properties

“…A schematic presentation for the arrangement of MWCNTs before percolation threshold and at percolation threshold in PC/MWCNT nanocomposites nanocomposites [23]. The current in a tunnel junction exponentially decreases with the barrier width.…”

Graphene nanoplate and multiwall carbon nanotube–embedded polycarbonate hybrid composites: High electromagnetic interference shielding with low percolation threshold

“…In recent times, tunneling conduction mechanism for various polymer composites has been well explained in the literature [27,28]. The tunneling conduction mechanism describes that the charge carriers move through a polymer composites across the insulating gaps between the nanofillers and generated electrical conduction in the polymer composites.…”

Selective Localization of Nanofillers: Effect on Morphology and Crystallization of PLA/PCL Blends

“…[13][14][15][16] Besides the welldefined copolymers, the anisotropic nanofiller can also be used to improve phase morphology of an immiscible blend system in some cases. In our previous work, [17,18] the multiwalled carbon nanotubes (CNTs) were introduced into the PLA/PCL (30:70 w/w) blend as a third component. It is found that the CNTs are selectively dispersed in the continuous PCL phase and the phase interface.…”