Electrical conductivity of carbon nanotube-filled miscible poly(phenylene oxide)/polystyrene blends prepared by melt compounding

Abstract

Conductive polymer composites (CPCs) have attracted tremendous attention from both academia and industry for several decades. Unfortunately, high conductive filler loadings required for current CPCs to obtain insulator/conductor transition (usually defined as percolation threshold) significantly limit their development. Although some methods have been put forward over the past decades, no-one is cost effective and not compatible with industrial production. Here we reported a low cost and high processing efficiency method to develop high-performance CPCs with low percolation threshold. Miscible poly(phenylene oxide)/polystyrene (PPO/PS) blends with different compositions were used as the matrices, and the dispersion of carbon nanotubes (CNTs) was tuned by the viscosity of the matrices which result from different blend ratio. The best dispersion state of CNTs as well as the best electrical conductivity of the nanocomposites were found at the intermediate matrix viscosity that had balanced effects on infiltration of polymer molecules and breakage of primary CNT agglomerates. The percolation threshold of PPO/PS(35/65)/CNTs nanocomposites is 63% lower than that of PS/CNTs nanocomposites because of the significantly better dispersion state of CNTs. The electrical resistivity of PPO/PS(35/65)/2%CNTs is about 103 Ω cm which is 9 orders of magnitude lower than that of PS/2%CNTs.