TY - JOUR A1 - Bodnaruk, Andrii V. A1 - Brunhuber, Alexander A1 - Kalita, Viktor M. A1 - Kulyk, Mykola M. A1 - Snarskii, Andrei A. A1 - Lozenko, Albert F. A1 - Ryabchenko, Sergey M. A1 - Shamonin (Chamonine), Mikhail T1 - Temperature-dependent magnetic properties of a magnetoactive elastomer: Immobilization of the soft-magnetic filler JF - Journal of Applied Physics N2 - The magnetic properties of a magnetoactive elastomer (MAE) filled with mu m-sized soft-magnetic iron particles have been experimentally studied in the temperature range between 150 K and 310 K. By changing the temperature, the elastic modulus of the elastomer matrix was modified, and it was possible to obtain magnetization curves for an invariable arrangement of particles in the sample and in the case when the particles were able to change their position within the MAE under the influence of magnetic forces. At low (less than 220 K) temperatures, when the matrix becomes rigid, the magnetization of the MAE does not show a hysteresis behavior, and it is characterized by a negative value of the Rayleigh constant. At room temperature, when the polymer matrix is compliant, a magnetic hysteresis exists where the dependence of the differential magnetic susceptibility on the magnetic field exhibits local maxima. The appearance of these maxima is explained by the elastic resistance of the matrix to the displacement of particles under the action of magnetic forces. KW - BEHAVIOR KW - composites KW - FIELD KW - GELS KW - hysteresis KW - Magnetorheological elastomers KW - MICROSTRUCTURE KW - PERMEABILITY KW - RAYLEIGH LAW KW - STRAIN Y1 - 2018 U6 - https://doi.org/10.1063/1.5023891 VL - 123 IS - 11 PB - AIP Publishing ER - TY - JOUR A1 - Bodnaruk, Andrii V. A1 - Kalita, Viktor M. A1 - Kulyk, Mykola M. A1 - Lozenko, Albert F. A1 - Ryabchenko, Sergey M. A1 - Snarskii, Andrei A. A1 - Brunhuber, Alexander A1 - Shamonin (Chamonine), Mikhail T1 - Temperature blocking and magnetization of magnetoactive elastomers JF - Journal of Magnetism and Magnetic Materials N2 - The magnetization of a magnetoactive elastomer (MAE) with microparticles of soft magnetic carbonyl iron embedded in a highly elastic matrix has been studied. It is shown that at high temperatures its magnetization curve has the form of a specific hysteresis loop. This hysteresis is attributed to the influence of displacement of magnetized particles in the elastically soft elastomer matrix under the effect of magnetic forces, leading to the change of magnetic interaction between the particles. In this case, there is a maximum in the field dependence of the magnetic susceptibility, the occurrence of which has been associated with the competition between rearrangement of particles, when they are displaced in a magnetic field, and saturation of particles' magnetization. When the MAE is cooled below approximately 225 K, both the magnetic hysteresis and the maximum in the field dependence of the magnetic susceptibility disappear. When the MAE material is cooled below the solidification temperature of the elastomer matrix, the displacements of the magnetic particles during magnetization are blocked by the rigid matrix. The magnetization reversal of the MAE is reversible. This means that the shape of subsequent magnetization loops remains constant and the sample returns into the initial non-magnetized state after the magnetic field is turned off. KW - Hysteresis loop KW - Magnetization reversal KW - magnetoactive elastomer KW - Magnetorheological elastomers KW - MICROSTRUCTURE KW - Solidification Y1 - 2019 U6 - https://doi.org/10.1016/j.jmmm.2018.10.005 VL - 471 IS - February SP - 464 EP - 467 PB - Elsevier ER - TY - JOUR A1 - Bodnaruk, A1 - Andrii V., A1 - Brunhuber, Alexander A1 - Kalita, Viktor M. A1 - Kulyk, Mykola M. A1 - Kurzweil, Peter A1 - Snarskii, Andrei A. A1 - Lozenko, Albert F. A1 - Ryabchenko, Sergey M. A1 - Shamonin (Chamonine), Mikhail T1 - Magnetic anisotropy in magnetoactive elastomers, enabled by matrix elasticity JF - Polymer N2 - Polydimethylsiloxane based magnetoactive elastomers demonstrate above the melting transition range (e.g. at room temperature) an induced uniaxial magnetic anisotropy, which grows with increasing magnetic field. By freezing a material down to 150 K, displaced iron microparticles are immobilized, so that the magnetic anisotropy can be measured. Magnetic anisotropy “constant” is a consequence of particle displacements and a characteristic of the energy of internal deformations in the polymer matrix. The maximum anisotropy constant of the filling is at least one order of magnitude larger than the shear modulus of the pure elastomer (matrix). In a magnetic field, the gain in the rigidity of the composite material is attributed to the magnetomechanical coupling, which is in turn a source of anisotropy. The concept of effective magnetic field felt by the magnetization allows one to explain the magnetization curve at room temperature from low-temperature measurements. The results can be useful for developing vibration absorbers and isolators. KW - Experimental methodology KW - Internal deformation KW - magnetic properties KW - magnetoactive elastomer KW - Magnetomechanical coupling KW - magnetorheological elastomer Y1 - 2019 U6 - https://doi.org/10.1016/j.polymer.2018.12.027 VL - 162 IS - January SP - 63 EP - 72 PB - Elsevier ER -