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Magnetorheological elastomers (MREs) are a kind of emerged smart material, where its responsive moduli in terms of mechanical and rheological properties are largely influenced by the presence of an external magnetic field. However, the incompatibility on the surface properties of its raw materials (fillers and matrix) may deteriorate the required properties of MREs. Therefore, in this study, the innovation of MRE by embedding silica nanoparticles as an additive has been experimentally investigated to strengthen the interactions between filler and matrix, thus resulted in enhancement of mechanical and rheological properties of MRE. The ethylene propylene diene monomer (EPDM)-based MREs were fabricated by mixing the EPDM with carbonyl iron particles (CIPs) as the main filler and different contents of silica nanoparticles (0 wt%–11 wt%) as an additive. The microstructures, magnetic properties and tensile properties of isotropic EPDM-based MREs were observed by using field emission scanning electron microscopy, vibrating sample magnetometer and Instron Universal Testing Machine, respectively. Meanwhile, the rheological properties were examined under oscillatory loadings in the absence and presence of magnetic field using rotational rheometer. The experimental results showed that the silica nanoparticles play a significant role in improving the properties of EPDM-based MREs. The adhesiveness of silica into CIPs has amended the interfacial interactions between CIPs and matrix by occupying the gaps between distributed CIPs within the MRE. Consequently, the addition of 11 wt% silica has not only improved the tensile properties (tensile strength and elongation at break), but also enhanced the MR effect compared to EPDM-based MREs without silica. Thus, incorporation of silica nanoparticles as an additive in EPDM-based MRE has the potential to be further explored and compromised to bring new innovation in real engineering applications. [ABSTRACT FROM AUTHOR]

The characteristics and behaviors of magnetorheological elastomer (MRE) within the elastic region are significantly important to demonstrate potentiality toward infinitesimal deformation in various applications. As MRE dynamically shears within an elastic region at constant small deformation, its significant consequence has long been a pending topic, hampered partly by the lack of empirical evidence. Therefore, this paper aimed to investigate the onset microscopically transformation of the MRE sample precipitated to storage modulus behavior under stress relaxation conditions. To achieve the aim, MRE with 70 wt% carbonyl iron particles was dynamically sheared at 1 Hz frequency and 0.01% strain for a designated period of test duration. The morphology evaluation of the sheared sample disclosed the development of permanent microplasticity in a very narrow region of shear bands. The deformation adequately reduced the storing energy ability of the MRE at a dominantly elastic behavior. The results revealed that the ability of MRE to store deformation energy slightly reduced by 0.3%–0.5% for the 2000 s test interval. This interesting onset phenomenon was successfully achieved, and the establishment of this early-stage deformation was undeniably important as preliminary data for catastrophic investigation at a longer duration. [ABSTRACT FROM AUTHOR]

Using catalytic methane decomposition techniques to produce H2 could advance renewable energy development. Selecting the proper catalyst for this method is essential for efficient hydrogen production. We used reactive molecular simulations to examine methane's decomposition reaction and the formation of H2 molecules on a Ni (1 1 0) surface. The results show that the dissociation of H atoms on Ni (1 1 0) surfaces produced H2 molecules. The reaction reached saturation because the Ni (1 1 0) surface was covered by methane fragments. These exhibited enhanced adsorption as the H atoms’ dissociation intensified. As the number of hydrogen atoms bonded to methane fragments decreased, the adsorption energy of methane fragments decreased. [ABSTRACT FROM AUTHOR]