Effects of silica on mechanical and rheological properties of EPDM-based magnetorheological elastomers

Abstract

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.

Temperature Dependent on Mechanical and Rheological Properties of EPDM-Based Magnetorheological Elastomers Using Silica Nanoparticles

“…Some unique phenomenon was observed in S1, as the interfacial defects clearly appeared after the temperature test [ 22 ]. Meanwhile, in S5 ( Figure 1 b), it is clearly observed that the CIPs and silica are embedded in the EPDM matrix, indicating a positive interfacial interactions between fillers and matrix [ 17 ]. In the meantime, some of the silica is adhered on the surface of CIPs and could be seen as a layer on the surface of CIP as seen in Figure 1 c. Basically, when the polymer is exposed to a high temperature (>50 °C), the molecules in the form of long polymer chains would vibrate and stretch, causing the chains to disentangle and slide more easily.…”

“…The values of elongation at break for the addition of 0, 3, 6, 9 and 11 wt.% were at 219.98%, 299.12%, 360.09%, 478.42% and 525.23%, respectively. This finding was mainly related to the adhesiveness of silica into CIPs that has improved the interfacial adhesion between fillers and matrix and enhanced the elasticity of the MRE [ 17 ]. The improved adhesion between fillers (CIPs and silica) and matrix has led to a better interaction on the surface of MRE because of the stress transfer between them.…”

“…The results revealed that the silane-modified silica has the highest tensile strength (22.22 MPa), followed by the silica filled SBR (10.84 MPa) and CB-filled SBR (10.74 MPa). In fact, the addition of 11 wt.% silica nanoparticles as an additive in the EPDM-based MRE has enhanced the tensile strength by almost 344%, increased from 3.18 to 14.13 MPa [ 17 ].…”

The Effect of Graphite Additives on Magnetization, Resistivity and Electrical Conductivity of Magnetorheological Plastomer

“…A small value of H c indicates good soft magnetic properties, which are desirable in the fabrication of smart materials as the magnet is easily demagnetized after removing the magnetic field. It should be noted that sample 6 could represent all the Gr–MRP samples (samples 2, 3, 4, and 5) since the content of CIP was the same at 70% and a few studies [ 38 , 39 ] have shown that the Gr does not substantially influence the magnetic properties, especially M s . The magnetization saturation was therefore mostly determined by the CIP content of MRP and Gr–MRP samples.…”

Effect of Volume Fraction on Shear Mode Properties of Fe-Co and Fe-Ni Filled Magneto-Rheological Elastomers

“…Magnetorheological Elastomers (MREs) are one such smart material, which when subject to an external magnetic field tend to change their mechanical and rheological properties such as stiffness, natural frequency, and damping capacity [ 16 , 17 , 18 , 19 ]. The controllability of the mechanical and rheological properties of MRE makes them resilient over a wide range of disturbance frequencies [ 20 , 21 ].…”