Low percolation threshold and high electrical conductivity in melt-blended polycarbonate/multiwall carbon nanotube nanocomposites in the presence of poly(ε-caprolactone)

Abstract

This study focuses on the electrical properties of polycarbonate (PC)/poly(ε‐caprolactone) (PCL)‐multiwall carbon nanotube (MWCNT) nanocomposites. MWCNTs were incorporated into thermoplastic PC matrix by simple melt blending using biodegradable PCL based concentrates with MWCNT loadings (3.5 wt%). Because of the lower interfacial energy between MWCNT and PCL, the nanotubes remain in their excellent dispersion state into matrix polymer. Thus, electrical percolation in PC/PCL‐MWCNT nanocomposites was obtained at lower MWCNT loading rather than direct incorporation of MWCNT into PC matrix. AC and DC electrical conductivity of miscible PC/PCL‐MWCNT nanocomposites were studied in a broad frequency range, 101−106 Hz and resulted in low percolation threshold (pc) of 0.14 wt%, and the critical exponent (t) of 2.09 from the scaling law equation. The plot of logσDC versus p−1/3 showed linear variation and indicated the existence of tunneling conduction among MWCNTs. At low MWCNT loading, the influence of large polymeric gaps between conducting clusters is the reason for the frequency dependent electrical conductivity. Transmission electron microscopy and field emission scanning electron microscopy showed that MWCNTs were homogeneously dispersed and developed a continuous interconnected network path throughout the matrix phase and miscibility behavior of the polymer blend. POLYM. ENG. SCI., 54:646–659, 2014. © 2013 Society of Plastics Engineers

Geometric percolation of hard nanorods: The interplay of spontaneous and externally induced uniaxial particle alignment

“…[3] Adding a critical amount of conductive particles like carbon nanotubes, graphene, or silver nanowires to common engineering plastics, for instance, can radically increase the electrical and thermal conductivity of the resulting nanocomposite material. [2,4] For the rational design of nanocomposites with the desired properties, a topic of broad relevance in the areas of optoelectronics, photovoltaics, and electromagnetic interference shielding, it is essential to understand and be able to control network formation in nanoparticle dispersions. [5][6][7][8][9][10] Nanoparticles in liquid dispersions do not actually need to make physical contact for a conducting network to emerge, as effective charge transport can take place via quantum mechanical tunneling.…”

Review on PCL, PBS, and PCL/PBS blends containing carbon nanotubes

“…No MWCNTs modification melt-mixing 0.2-0.5 wt% 0.20 wt% [40] No MWCNTs modification melt-mixing 0.05-5.0 wt% 0.30 wt% [41] No MWCNTs modification melt-mixing 0.5 wt% 2.00 wt% [42] Nitric acid-treatment in situ polymerization 0.5-5.0 wt% - [64] No MWCNTs modification melt blending 0.35-7.0 wt% 0.14 wt% [49] PC/MWCNTs masterbatch melt blending 0.5-4.0 wt% 0.5-1.0 wt% [50] interconnecting conductive pathway. The electrical conductivity values increased by more than one order of magnitude.…”

“…of PC as matrix polymer in the preparation of CNTs masterbatches [49,50]. The PC/CNTs masterbatch can be added to PCL to improve the dispersion of CNTs in the PCL matrix.…”

A review on the electrical and electrochemical behavior of composites based on carbon nanotube, graphene and their derivatives

“…Khatua et al have studied the electrical conductivity of different PC/MWCNT composites [272][273][274][275][276][277] to achieve high electrical conductivity at low MWCNT loading with very low percolation threshold. They have prepared PC/MWCNT composites by melt dilution of PC with ABS/MWCNT mixture [272].…”