Economical conductive graphite‐filled polymer composites via adjustable segregated structures: Construction, low percolation threshold, and positive temperature coefficient effect

Abstract

AbstractThe economical graphite‐filled thermoplastic urethane/ultra‐high molecular weight polyethylene (TPU/UHMWPE) composites with the segregated structure were constructed by the combination of mechanical crushing and melt blending method. The low percolation threshold of 1.89 wt% graphite in the adjustable segregated composites was obtained and high electrical conductivity was about 10−1 S m−1 at 10 wt% graphite loadings owing to the formation of three‐dimensional conductive networks. Moreover, when the graphite loadings were over the percolation threshold, the remarkable positive temperature coefficient (PTC) effect of electrical resistivity for TPU/UHMWPE‐Graphite composites were achieved, originating from the combined thermal motion of TPU and UHMWPE. Meanwhile, the outstanding repeatability of PTC effects was obtained after 5‐time cycles. Therefore, economical conductive polymer composites were still the promising field in the practical application of PTC materials.