Mechanical and magnetic response of magneto-rheological elastomers with different types of fillers and their hybrids

The use of secondary reinforcing fillers such as graphene or multi-wall carbon nanotube (CNT) for improving mechanical properties is an effective strategy to obtain high performance magneto-rheological elastomers (MREs). Therefore, MREs were prepared via solution mixing of room-temperature-vulcanized silicone rubber (RTV-SR) and iron oxide (Fe3O4), and hybridized with iron wire, Few-layer graphene (FLG), and CNT as secondary nanofillers. The isotropic mechanical properties were studied through compressive tests, and their compressive moduli and reinforcing factors were determined. From these studies, it was found that CNT-based hybrid MREs show the highest compressive mechanical properties. For example, at 80 per hundred parts of rubber (phr), the compressive modulus was 3.5 MPa (RTV-SR/Fe3O4), 4.1 MPa (RTV-SR/Fe3O4-FLG), 5.5 MPa (RTV-SR/Fe3O4-CNT), and 3.7 MPa (RTV-SR/Fe3O4-iron wires). A nanofiller with higher aspect ratio (CNT), has a strong effect on the isotropic mechanical properties, whereas a lower aspect ratio nanofiller (FLG) has a greater effect on magnetic sensitivity. Although iron wires with lower specific surface areas can only improve the mechanical properties slightly, they can improve the magnetic sensitivity of MREs because of its stronger magnetic behavior.