Low percolation threshold carbon-black/nitrile-butadiene-rubber composites and their electromagnetic shielding effects

Nitrile-butadiene-rubber composites, filled with super conducting carbon black, are successfully prepared with low percolation threshold, high conductivity and electromagnetic shielding effectiveness. Percolation theory is used to represent the system's conductivity, and the corresponding result is close to the experimental value. The fitting curve also gives the weight fraction threshold and conductivity exponent of the conducting polymer. The percolation threshold of the composite is 9.2 phr, which is much smaller than previous homologous findings and lower than the value of short carbon fiber counterparts reported. The volume resistivity becomes 3.17 Ω · cm for the 20 phr sample and decreases to 0.66 Ω · cm for the 40 phr sample. At 1.8 GHz for 40 phr sample, the shielding effectiveness is -43 dB.