Synergistic effect of carbon fibers on the conductive properties of a segregated carbon black/polypropylene composite

•The ultra-low percolation threshold of 0.94 vol% has been achieved.•This result was attributed to the shish–calabash-like conductive network.•The synergistic effect of the hybrid conductive fillers CF/CB was evaluated.•The mechanical properties of the segregated composite have also been improved.

Under the assistance of carbon fibers (CFs) with a large aspect ratio, an evident reduction in the percolation threshold of a segregated carbon black (CB)/polypropylene (PP) conductive polymer composite (CPC) has been achieved. The origin of the ultra-low percolation threshold 0.94 vol% is ascribed to the design of a shish–calabash-like conductive network, where the CFs function as bridges between the segregated CB particles and CB particles act as calabashs contributing to the conductive framework. This interesting microstructure causes a synergistic effect on the conductive properties. A model is proposed to evaluate the percolation behavior of the unique CF/CB/PP composite.

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