Theoretical Prediction of Electrical Conductivity Percolation of Poly(lactic acid)—Carbon Nanotube Composites in DC and RF Regime

Abstract

Polymer composites based on polylactic acid (PLA) reinforced with 0.25–5 wt.% of carbon nanotubes (CNTs) were synthesized by melt blending. The static (DC) and microwave (RF) electrical conductivity have been investigated on the PLA–CNT composites. The electrical percolation threshold has been theoretically determined using classical models of percolation in order to predict the conductivity of the different nanocomposites. Through the fitting process, it has been found that the percolation threshold is obtained at 1 wt.% of CNTs in the DC regime and reached below 0.25 wt.% of CNTs in the microwave regime. Among the Mamunya, McLachlan, or GEM models, the McCullough model remarkably fits the experimental DC and RF electrical conductivities. The obtained results are correlated to the electrical properties of a range of CNT-based composites, corresponding to the percolation threshold required for a three-dimensional network of CNTs into the polymer matrix.

Low-Dimensional Structures for Smart Materials and Composites: Preparation, Properties and Applications

“…This extensive research comes from the relatively cheap/easy processability of polymers when added with nanofillers, and the possibility to impart to the material electrical/sensing properties [5]. Beltran et al [6] focused on polylactic acid (PLA) polymer reinforced with CNTs at different weight percentages (CNTs 0.25-5 wt.%). The authors investigated the direct current (DC) and radio frequency (RF) microwave electrical conductivities of composites and calculated percolation thresholds using classical models.…”