Dielectric studies of some rubber materials at microwave frequencies

Studies on dielectric property of natural rubber (NR) and some synthetic rubbers viz., styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), ethyl vinyl acetate rubber (EVA), PVC nitrile, butyl rubber, silicon rubber, neoprene, chlorosulphonated monomer, polyacrylic, fluorocarbon rubber, reclaimed rubber and polyblends of natural rubber with NBR and EPDM were carried out using microwave test bench system at X-band and K-band microwave frequencies. Analysis of dielectric property is inevitable since they determine the end electrical applications, per se, insulation. Present work is aimed at the determination of dielectric constant by using the method proposed by Robert and Von-Hippel. A systematic analytical approach was adopted in evaluating the data generated on dielectric constants for a variety of rubber materials. Interesting results were obtained by comparing dielectric constant values. The effect of microwave frequency, namely 9.6 GHz and 26GHz, as well as chemical modification brought about by vulcanization and reinforcement on dielectric constant values was probed. It appears from the study that among all samples polyblend of NR with EPDM posses interesting dielectric behaviour making it unique.