Enhanced reproducibility of positive temperature coefficient effect of TPO/HDPE blends via elastic crosslinking

Positive temperature coefficient (PTC) materials usually have NTC effect, and the effect is poor. In this paper, conductive carbon black (CB) and amorphous elastomer (TPO) were introduced into high-density polyethylene (HDPE) by melting mixing and hot pressing methods and treated with peroxide crosslinking to improve the PTC properties of conductive composites. The results show that the percolation threshold reduces from 24 wt% to 22 wt% for crosslinked elastic networks. At the same time, the room temperature resistance of the composite material does not show monotonicity after three cycles, which has good reproducibility and eliminates the NTC effect of the composite material. This work provides both a simple way to produce high-performance PTC materials and a new idea to improve the stability of PTC materials.