Study on the positive and negative temperature coefficient effects of composite

A crosslinked conductive material prepared by melt-mixing of CB (carbon black) and PE (polyethylene) was ground into fine powder and screened, producing the composite filler. Then a new conductive composite was prepared by melt-mixing of the composite filler and PP. A double-positive temperature coefficient (double-PTC) was observed in the composite. The phenomenon related to the large thermal expansion due to the consecutive melting of high-density polyethylene (HDPE) and polypropylene (PP) crystallites phase. At the same time, the negative temperature coefficient effect (NTC) was eliminated basically. This conclusion was confirmed by the morphology of SEM of the composite.