Electric conductivity of heterogeneous polymer blends filled with carbon black

The electric conductivity and morphology of a series of polyethylene blends with elastomers filled with carbon black were studied. For all the heterogeneous blends investigated the phenomenon of superadditive electric conductivity was observed under certain conditions. If the concentration of carbon black in each phase is lower than;the critical value, this phenomenon is caused by a partial transfer of carbon black to the polymer interfaces. When the carbon black concentration in one of the blend phases is above the critical value, the observed phenomenon is explained to a marked extent by the localization of carbon black in one of the polymer blend phases, while the absence of the above-mentioned transfer is completely related to this process.