Effects of Petroleum-Based Oils as Dispersing Aids on Physicochemical Characteristics of Magnetorheological Elastomers.

Norizatie Muhammad Zaki,Nurul Azhani Yunus,Muhamad Shakir Yusoff,Nor Aziyatul Izni,Irfan Bahiuddin,Siti Aishah Abdul Aziz,Saiful Amri Mazlan

doi:10.3390/ma14227026

Abstract

This paper investigated the effects of petroleum-based oils (PBOs) as a dispersing aid on the physicochemical characteristics of natural rubber (NR)-based magnetorheological elastomers (MREs). The addition of PBOs was expected to overcome the low performance of magnetorheological (MR) elastomers due to their inhomogeneous dispersion and the mobility of magnetic particles within the elastomer matrix. The NR-based MREs were firstly fabricated by mixing the NR compounds homogeneously with different ratios of naphthenic oil (NO), light mineral oil (LMO), and paraffin oil (PO) to aromatic oil (AO), with weight percentage ratios of 100:0, 70:30, 50:50, and 30:70, respectively. From the obtained results, the ratios of NO mixed with low amounts of AO improved the material physicochemical characteristics, such as thermal properties. Meanwhile, LMO mixed the AO led to the best results for curing characteristics, microstructure observation, and magnetic properties of the MREs. We found that the LMO mixed with a high content of AO could provide good compatibility between the rubber molecular and magnetic particles due to similar chemical structures, which apparently enhance the physicochemical characteristics of MREs. In conclusion, the 30:70 ratio of LMO:AO is considered the preferable dispersing aid for MREs due to structural compounds present in the oil that enhance the physicochemical characteristics of the NR-based MREs.

Highlights

Magnetorheological elastomers (MREs) are a kind of smart material, whose rheological properties can be continuously, reversely, and rapidly controlled by an external magnetic field due to the existence of magnetic particles embedded in the elastomer matrix [1,2,3,4,5,6,7].Over the past decade, the properties of MREs have attracted immense attention, and they have use in several applications, such as prosthetic devices, spring elements, automotive bushing, medical devices, vibration absorbers, and piezo-sensors [8,9,10]
MREs can be fabricated as anisotropic or isotropic; in the former, a magnetic field is applied during the curing process; for isotropic, the curing process is performed without a magnetic field, producing either a uniform or random distribution of magnetic particles
The effect of the addition of different ratios of petroleum-based oils (PBOs) is first discussed because the curing process is crucial for the MRE samples to become crosslinked

Summary

Introduction

Magnetorheological elastomers (MREs) are a kind of smart material, whose rheological properties can be continuously, reversely, and rapidly controlled by an external magnetic field due to the existence of magnetic particles embedded in the elastomer matrix [1,2,3,4,5,6,7].Over the past decade, the properties of MREs have attracted immense attention, and they have use in several applications, such as prosthetic devices, spring elements, automotive bushing, medical devices, vibration absorbers, and piezo-sensors [8,9,10]. Magnetorheological elastomers (MREs) are a kind of smart material, whose rheological properties can be continuously, reversely, and rapidly controlled by an external magnetic field due to the existence of magnetic particles embedded in the elastomer matrix [1,2,3,4,5,6,7]. Anisotropic MREs contain chain-like or columnar structures of magnetic particles [11,12]. The matrix, magnetic particles, and additives are the main components of MREs, all of which have shown great influences on their properties. SiR faces a problem when magnetic particles are implemented in the MREs, since the particles cannot be blended with an SiR matrix [13,14]. SiR is soft rubber, and lacks mechanical properties such as low impact loading, which limits its application [15]

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