Dependence of THz signals on carbon black compounding amount in vulcanized rubber

Dispersion of carbon black (CB) is one of the most important factor to keep better quality of rubber products. Our research group is developing evaluation methods using terahertz technology for rubber estimation during the product processes. In this paper, dependence of the THz signals on the CB compounding amount in vulcanized rubber is reported. It was found that both of the THz absorbance and THz reflectance were proportional to the CB concentration, however, at the higher CB amount, the THz absorbance did not obeyed relation of proportion, which suggests rather complicated THz transmission in vulcanized rubber.