Porous magnetic materials based on EPDM rubber filled with carbonyl iron particles

This paper deals with a possibility to prepare porous magnetic elastomers whose mechanical behavior can be controlled by means of a magnetic field. The elastomers under investigation are based on ethylene propylene diene rubber (EPDM) filled with carbonyl iron particles. The foaming agent based on azodicarbonamide was used at 2 loading levels to control their porous character and the magneto-mechanical behavior was compared with non-porous magnetic EPDM system. The non-porous systems exhibited the highest magnetorheological efficiency even though the porous systems showed lower values of storage modulus in the inactive state. Porous systems also exhibited lower mechanical hysteresis when compared to non-porous one during single-strain measurements with increasing/decreasing magnetic field due to pores which increase a distance between particles and thus lower the strength of magnetic network created at high magnetic fields. Porous systems can be potentially utilized in applications in which conventional magnetorheological elastomers are too tough, thus, porous systems offer magnetorheological material with properties between magnetorheological fluids and solid elastomers.