Development of Underground Composite Pipes Having Health Monitoring Functions

Abstract

In this paper, carbon blacks (CB) and charcoal powders (CP) were used as conductive fillers for fabricating conductive polymer composites. Those carbon fillers were dispersed into high density polyethylene (HDPE) by a melt compounding method using a twin screw extruder. The resulting composite with pellet shape was used to produce specimens for the evaluation of their electrical properties. The electrical properties of the polymer composite were evaluated by the four-point probe array method following JIS K 7194. The HDPE/CB/CP composites showed low volume resistivity when the filler contents were 9 wt% of CB and 20 wt% of CP, which indicated sufficient dispersion of CB and CP within HDPE to form a conductive network. In order to observe the dispersion state of fillers in the HDPE/CB/CP composites, 3-D computed tomography (CT) was used. In addition, the tensile properties of the HDPE/CB/CP composites were also measured to verify the reinforcement effect by carbon fillers. Furthermore, HDPE/CB/CP composite pipes were fabricated and their electrical properties were investigated by the four-point probe array method.