Electrical Properties of Single Walled Carbon Nanotube Reinforced Polystyrene Composites

Abstract

Composites of carbon nanotubes (CNT) in polymeric matrices have attracted considerable attention in the research communities due to their good electrical conductivity, high stiffness and high strength at relatively low CNT contents. Effective utilization of CNT in composites depends primarily on the ability to disperse them homogeneously throughout the polymer matrix, avoiding the formation of bundles due to van der Waals interactions existing between the nanotubes. In this work composites of polystyrene at various percentages of SWNT were fabricated using Latex Technology technique, a polymer type‐independent method based on using a surfactant as a dispersing agent. An electrical characterization of SWNT composites was performed both in DC and AC modes. From the analysis of DC data a percolative behavior was found for the conductivity as function of SWNT content. The innovative contribution of this work consists in the modeling of the composite material upon its electrical properties. AC measurements and the analysis of impedance as function of angular frequency lead to the formulation of an equivalent circuit able to model the composite material in correspondence of the percolative threshold.

Influence of carbon nanotube clustering on the electrical conductivity of polymer composite films

“…Notice that the aspect ratio of the employed CNTs is in the range of 80-300 and therefore the CNT dispersion state should be the most influential factor on the composite electric conductivity, according to a previous investigation by Li et al [11]. Typical values of t reported for CNT-polymer composites are in the range of 1.3-4, see [10], although a few works report values of t of ~4.9 [23] and even higher than 7 [24]. Mathematically, since φ-φ c is a small fraction (<1), a lower value of t in Equation (2) means more abrupt increments in electrical conductivity in the vicinity of percolation.…”

Electrical conductivity, phase behavior, and rheology of polypropylene/polystyrene blends with multi-walled carbon nanotube

“…This is an unexpected result since it is known that MWNT has very high thermal stability. But this acceleration behavior of thermal decomposition was also reported by several literatures (Antonucci et al 2007;Yang et al 2004). However, detailed investigation is necessary to understand exact mechanism of acceleration behavior.…”

“…This is known as a critical weight or volume percentage of fillers required for building up a continuous electrically conductive network throughout the polymer matrix and actually depends on the aggregation structure, porosity, average size, and size distribution of the conducting particles (Sircar and Lamond 1978), and on the polymer rheology (Sumita et al 1986) and processing conditions as well. Among the electrically conductive fillers, carbon nanotube-based composite tends to have higher conductivity and lower percolation threshold than either carbon black or carbon fiber based one (Antonucci et al 2007;Hwang et al 2010;Wu et al 2011;Wu and Shaw 2006). It is attempting to attribute this and other low thresholds simply to the high aspect ratio of the conductive filler.…”

“…Generally, carbon nanotubes have strong tendency to agglomerate and can easily become entangled owing to their high aspect ratio. High loading fractions favor agglomeration not only because the particles come into contact more often, but also because there can be a shortage of polymer matrix to wet-out the surface of the filler (Antonucci et al 2007;Brown and Stevens 2007;Pötschke et al 2002;Wu and Shaw 2006).…”

The plasticizer‐assisted formation of a percolating multiwalled carbon nanotube network in biodegradable poly(L‐lactide)

“…[1][2][3][4][5][6] In particular, formation of a percolating CNT network in the polymer matrix, mostly depending on the dispersion of CNTs, is responsible for the significant conductivity enhancement as well as nonterminal rheological behaviors. Thus, achieving an appropriate dispersion of inorganic CNTs in the polymer matrix is a key issue to ensure low percolation threshold in parallel with high mechanical performance.…”