Temperature-Dependent Magnetic Properties of Magnetorheological Elastomers

We report on an investigation of the temperature-dependent magnetic properties of magnetorheological elastomers (MREs). These are a class of composites that consist of magnetically permeable particles dispersed in a nonmagnetic polymeric matrix. Under the application of an external magnetic field, a large deformation occurs altering the mechanical properties of these materials. Due to their magnetoelastic coupling response, these materials are finding an increasing interest among the scientific community. These polymer-based composites’ performance depends on many factors, which temperature is one of the biggest influencing factors requiring further investigation. In this work, the magnetic properties of isotropic and anisotropic polyurethane-based MRE with different iron (Fe) particle loading fractions (50%, 60%, 70%, and 80% by weight) were investigated under different temperatures. From the analysis, the magnetization curves of these materials are observed to overlap for different measured temperature values. The variation of various magnetic properties including saturation magnetization and differential susceptibility with temperature was also determined. The results show a ~2.5% decrement in the saturation magnetization for each of the loading fractions, between the lowest (300 K) and the highest (400 K) measured temperature. On the other hand, the initial differential susceptibility exhibits different trends with increasing temperature. Generally, the magnetization response of these materials is seen to be only slightly sensitive to temperature changes. In addition, the magnetization response is observed to be highly dependent on particle loading fractions and particle orientation within the elastomer.