Anisotropic percolation conduction in elastomer-carbon black composites investigated by polarization-sensitive terahertz time-domain spectroscopy

Autor: Shinichi Watanabe, Makoto Okano, Misako Fujii
Rok vydání: 2017
Předmět:
Zdroj: Applied Physics Letters. 111:221902
ISSN: 1077-3118
0003-6951
Popis: We investigated the draw ratio (DR) dependence of the anisotropic dielectric function and conductivity of styrene butadiene rubbers (SBRs) with different carbon black (CB) concentrations by polarization-sensitive terahertz time-domain spectroscopy. From the frequency dependence of the conductivity in the unstretched SBRs ranging from direct current to terahertz frequencies, it is found that the SBR with a CB concentration above 30 wt. % exhibits percolation conductivity. We investigated the spectral shape of the dielectric function and conductivity of the SBR samples below and above the percolation threshold for two representative DRs in the terahertz frequency region. We found that the DR dependence of the spectral shape is well explained by the effective medium approximation, except for the sample with the CB concentration above 30 wt. % under the unstretched condition. The conductivity in that sample remarkably changes in the low terahertz frequency region, which suggests a change in the CB network by ...
Databáze: OpenAIRE