In this article, the positive temperature coefficient (PTC) and interaction based on low-density polyethylene (LDPE) filled with the loading of graphite (G) powder have been investigated. The dependence of the room temperature resistivity on filler content showed the significant decrease. The PTC behavior enhanced with increasing graphite content but this was not always the case. The maximum PTC effect was observed in LDPE/G composites (G, 45 wt %) with the relatively low room temperature resistivity. The thermal behavior was measured by differential scanning calorimetry (DSC). The structure characteristic for LDPE/G composites was examined by X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), and stress-strain test. The fact was revealed that the slight interaction between LDPE matrix and graphite may lead to change the thermal-electric properties of the PTC materials. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 2338-2343, 2012