Rheological properties of isotropic magnetorheological elastomers featuring an epoxidized natural rubber

Abstract

This study presents principal field-dependent rheological properties of magnetorheological elastomers (MREs) in which an epoxidized natural rubber (ENR) is adopted as a matrix (in short, we call it ENR-based MREs). The isotropic ENR-based MRE samples are fabricated by mixing the ENR compound with carbonyl iron particles (CIPs) with different weight percentages. The morphological properties of the samples are firstly analysed using the microstructure assessment. The influences of the magnetic field on the viscoelastic properties of ENR-based MREs are then examined through the dynamic test under various excitation frequencies. The microstructure of MRE samples exhibits a homogeneous distribution of CIPs in the ENR matrix. The dramatic increment of storage modulus, loss modulus and loss tangent of the ENR-based MREs are also observed from the field-dependent rheological test. This directly demonstrates that the stiffness and damping properties of the samples can be adjusted by the magnetic field. It is also seen that the CIP content, exciting frequency and the magnetic field essentially influence the dynamic properties of the ENR-based MREs. The strong correlation between the magnetization and the magneto-induced storage modulus could be used as a useful guidance in synthesizing the ENRbased MREs for certain applications.

Linear magneto-viscoelastic model based on magnetic permeability components for anisotropic magnetorheological elastomers

“…The particle distribution is an important characteristic of MREs, because their properties are completely dependent on it. Isotropic MRE samples are prepared by vulcanisation without an external magnetic field; these samples have a random particle distribution [2,3]. However, if an external magnetic field is applied during the vulcanisation process, particles are aligned in the direction of the magnetic field, and consequently particle chains or thicker chain aggregates are obtained; these samples are called anisotropic MREs [4,5].…”

“…In order to obtain a better fitting to experimental data, more elements have been introduced increasing the number of fitting parameters [10]. 2 The fractional derivative model can be used to decrease the number of material parameters, and these parameters have a physical meaning [11]. Using these advantages the viscoelastic behaviour of isotropic [7,12] and anisotropic [13,14] MREs have recently been modelled using fractional derivative models.…”

Effect of Curing Current on Stiffness and Damping Properties of Magnetorheological Elastomers

“…This can be explained by the formation of the chain-like structures during the curing process. As the magnetic field strength is stronger, the chain-like structure becomes thicker and stronger which means that the interaction between the particles become stronger thus reducing the friction between the particles [33,34]. Therefore, as the friction energy between the particles decreases, the energy dissipations is lowered, which results in the decrement of loss factor.…”

Microrheology of magnetorheological silicone elastomers during curing process under the presence of magnetic field

“…The magnetization of MREs becomes pronounced with increasing SiCIPs content, demonstrating that a potential to alter the properties under the relatively low magnetic field intensity employed. [19][20][21] Fig . 3 presents MSD curves of the MREs under different magnetic field intensities at 25 • C. In the initial stage before silicone curing, MSD increases nearly linearly with t dec due to the free movement of SiCIPs in the viscous matrix with a relatively low viscosity.…”

“…14 MREs, as a solid analogue of MRFs in which magnetic particles are locked in an elastomeric polymer matrix to overcome particle sedimentation, have attracted significant interest in recent years regarding their potentials in engineering applications. [11][12][13][14][15][16][17][18][19][20][21] Thus far, their rheological characteristics have been extensively studied. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] However, the structural evolution during the process of elastomer curing under magnetic field is not yet illuminated.…”