Formation of Conductive Networks with Both Segregated and Double-Percolated Characteristic in Conductive Polymer Composites with Balanced Properties

Abstract

Morphological control of conductive networks involves the construction of segregated or double-percolated conductive networks is often reported to reduce the electrical percolation threshold of conductive polymer composites (CPCs) for better balance among electrical conductivity, mechanical properties, and filler content. Herein, the construction of conductive networks with both segregated and double-percolated characteristics is achieved based on polypropylene (PP)/polyethylene (PE) and multi-wall carbon nanotubes (CNTs). CNTs were firstly dispersed in PE; then PE/CNTs were compounded with PP particles well below the melting temperature of PP. It is observed that the percolation threshold (pc) decreases with increasing PP particle size (size 3.6 mm, pc=0.08 wt %), which agrees with previous theoretical prediction and experiment in much smaller particle size range. To further study this, the amount of CNTs in PE is varied. It is shown that the degree of PE/CNTs coating on PP particles varies with CNTs as well as PE content in these composites, and have significant influence on the final electrical property. Furthermore, a model combines classical percolation theory and model for segregated network has been proposed to analyze the effect of particle size, degree of coating and thickness of coating on the percolation behavior of these CPCs. In such a model the percolation of CNTs in PE phase as well as PENT phase in the segregated structure can be described. Overall, through such method, a much better balance among mechanical property, conductivity, and filler content is achieved in these CPCs comparing with the results in literature.

Effect of phase transitions on the electrical properties of polymer/carbon nanotube and polymer/graphene nanoplatelet composites with different conductive network structures

“…Carbon nanofillers, such as carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs), are widely used for conductive polymer composites (CPCs) due to their excellent conductivity and high aspect ratio. A low electrical percolation threshold can be achieved for polymer/CNT and polymer/GNP composites, particularly when a segregated conductive network structure is achieved in the polymer matrix . By way of example, Lin et al .…”

Improved electrical conductivity of PDMS/SCF composite sheets with bolting cloth prepared by a spatial confining forced network assembly method

“…3 shows the relationships between direct current (DC) electrical conductivity and ller content of PDMS/SCF composite sheets by different processes of P1, P2 and P3, which follows the conductive percolation theory. [21][22][23][24] When the ller content is low, the change of the composites conductivity is not obvious. With the ller content increasing to a certain degree, a dramatic improvement of magnitude in the conductivity of composites happens, which changes the polymer from insulator to conductor.…”

“…[14][15][16][17][18][19][20] It is a conventional method to construct such a network mainly by increasing the amount of conductive llers until percolation appears. [14][15][16][21][22][23][24] As most polymers have very low electrical conductivity, the electrically conductive llers are incorporated into polymers to fabricate CPCs. Many efforts have been focused on how to build conductive networks in polymer matrixes using electrically conductive llers with high aspect ratio, including carbon black particles, carbon ber, graphite ake, carbon nanotubes (CNTs) and graphene.…”

Substantially improving mechanical property of double percolated poly(phenylene sulfide)/poly(arylenesulfide sulfone)/graphene nanoplates composites with superior electromagnetic interference shielding performance

“…In such double percolated conductive networks, conductive fillers are incorporated directly into incompatible binary polymer blends and selectively located in one of the polymer matrices or at the interfaces . For instance, the carrier polymer polyethylene (PE) for CNTs was used to prepare CNT/PP/PE CPCs and the interfacial adhesion between the PP granules was significantly enhanced by the presence of conductive PE/CNTs binder, resulting in the balance among electrical conductivity and mechanical property . Shi et al .…”