Conducting carbon black filled NR/IIR blend vulcanizates: Assessment of the dependence of physical and mechanical properties and electromagnetic interference shielding on variation of filler loading

A series of natural rubber/ butyle rubber NR/ IIR (70/30) loaded with general purpose furnace (GPF) carbon black have been produced on a laboratory scale, and their electrical and mechanical properties were investigated. The percolation threshold concentration has been described using Kirkpatrick and Zallen model. The percolation model gives a suitable explanation, within the experimental data of the studied samples. The thermal stability of composites was also investigated. It was found that the stability of high filler content blend was better than that of low filler content, due to strong polymer-filler interaction at high filler concentrations. Variation of mechanical properties of carbon black-filled compounds with the filler content was also investigated. Electromagnetic interference (EMI) shielding characteristics of these composites were studied. The measurements of shielding effectiveness (SE) were carried out in different frequency ranges from 0.5-5 GHz and it increases with the increase in filler loading. SE values were in the range of 7-30 dB.