Dielectric properties and stress–strain measurements of chloroprene rubber based on different carbon black fillers

A systematic dielectric study of 1 kHz was carried out on chloroprene rubber, mixed with different types of carbon black and different concentrations. The measurements were carried out at room temperature (25°C). It was found that better dielectric properties cannot be achieved when the carbon black concentration exceeds 60% for MT, 40% for SRF, and 20% for both HAF and SAF. In addition, the relation between the dielectric constant ε and the modulus of elasticity E for the different mixes were studied. From this study it was found that, up to certain carbon black volume concentration (depending on the filler type), the modulus equation Ef = E0 (1 + 0.67φC + 1.62φ2) can be used to relate the dielectric properties εf and εo of carbon black filled and unfilled rubber compounds. The dielectric measurements were also related to the particle size and the structure of carbon black.