Epoxy resin/polyetherimide/carbon black conductive polymer composites with a double percolation structure by reaction-induced phase separation

Abstract

A novel double-percolation structural conductive polymer composite based on epoxy/polyetherimide/carbon black was prepared for the first time. The electrical property, phase structure of the composite and the selective distribution of carbon black were investigated. The results show that a reaction-induced phase separation between epoxy and polyetherimide can be observed in epoxy/polyetherimide/carbon black composites. In the blend with 16 wt% polyetherimide, polyetherimide phase changes from a dispersed phase to a three-dimensionally continuous phase, while epoxy converts to a globular dispersed phase. The selective distribution of carbon black in the blends is that almost all carbon black particles are located in polyetherimide phase. Accordingly, a double-percolation structure is formed when carbon black content comes to the percolation threshold in polyetherimide phase. In fact, the percolation threshold of carbon black reduces to 0.5 wt% in the blend with 16 wt% polyetherimide.