• Elastomers and Composites
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• v.46 no.4
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• pp.311-317
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• 2011

The neodymium magnet inserted mold was proposed to orient magneto-responsible particles efficiently. The anisotropic magneto-rheological elastomer(MRE) was prepared using the new mold and the optimum amounts of the particles was 30 vol.%. As the orientation of particles was increased, the tensile strength of MRE was decreased, while the hardness of MRE was increased. It was found that the MRE containing 30 vol.% of magneto-responsible particles showed the maximum magneto-rheological effect. The ratio of shear modulus shift was 59% at the input current of 3 A. The transmissibility of MRE was decreased with increasing the input current and loading amounts of magneto-responsible particles. Therefore, the damping property of MRE could be improved by preparing the anisotropic MRE.

• Elastomers and Composites
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• v.51 no.2
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• pp.113-121
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• 2016

Magneto-rheological elastomer (MRE) is a material which shows reversible and various modulus under magnetic field. Comparing to conventional rubber vibration isolator, MREs are able to absorb broader frequency range of vibration. These characteristic phenomena result from the orientation of magnetic particle (i.e., chain-like formation) in rubber matrix. In this study, silicone rubber was used as a matrix of MREs. Carbonyl iron particle (CIP) was used to give magnetic field reactive modulus of MRE. The surface of the CIP was modified with chemical reactants such as silane coupling agent and poly(glycidyl methacrylate), to improve interfacial adhesion between matrix and CIP. The mechanical properties of MREs were measured without the application of magnetic field. The results showed that the tensile strength was decreased while the hardness was increased with the addition of CIP. Also, surface modification of CIP resulted in the improvement of physical properties of MRE, but the degree of orientation of CIP became decreased. The analysis of MR effect was carried out using electromagnetic equipment with various magnetic flux. As the addition of CIP and magnetic flux increased, increment of MR effect was observed. Even though the surface modification of CIP gave positive effect on the mechanical properties of MRE, MR effect was decreased with the surface modification of CIP due to decrease of CIP orientation. Throughout this study, it was found that the loading amounts of CIP affected the mechanical properties of MRE, and surface property of CIP was an important factor on MR effect of MRE.

• Smart Structures and Systems
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• v.12 no.1
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• pp.1-22
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• 2013

Magnetic nanoparticle based bioseparation in microfluidics is a multiphysics phenomenon that involves interplay of various parameters. The ability to understand the dynamics of these parameters is a prerequisite for designing and developing more efficient magnetic cell/bio-particle separation systems. Therefore, in this work proof-of-concept experiments are combined with advanced numerical simulation to design and optimize the capturing process of magnetic nanoparticles responsible for efficient microfluidic bioseparation. A low cost generic microfluidic platform was developed using a novel micromolding method that can be done without a clean room techniques and at much lower cost and time. Parametric analysis using both experiments and theoretical predictions were performed. It was found that flow rate and magnetic field strength greatly influence the transport of magnetic nanoparticles in the microchannel and control the capturing efficiency. The results from mathematical model agree very well with experiments. The model further demonstrated that a 12% increase in capturing efficiency can be achieved by introducing of iron-grooved bar in the microfluidic setup that resulted in increase in magnetic field gradient. The numerical simulations were helpful in testing and optimizing key design parameters. Overall, this work demonstrated that a simple low cost experimental proof-of-concept setup can be synchronized with advanced numerical simulation not only to enhance the functional performance of magneto-fluidic capturing systems but also to efficiently design and develop microfluidic bioseparation systems for biomedical applications.

• Elastomers and Composites
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• v.49 no.4
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• pp.267-274
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• 2014

Self vulcanizable blend system for magnetorheological elastomer (MRE) has been studied by dispersing magneto responsible particle (MRP) on elastomeric matrix. Chloroprene rubber was modified with maleic anhydride (MAH) using heat and pressure which is called dynamic maleation process. The optimum graft ratio of MAH was found at 10 phr contents and reaction temperature of $100^{\circ}C$. This could be confirmed by FT-IR analysis. Epoxided natural rubber (ENR) was blended with modified CR-g-MAH for self vulcanization. The optimum amounts of ENR was 30 wt% in terms of scorch time and curing rate. MRE was manufactured by electromagnetic equipment and orientation of MRE was confirmed by SEM. Finally, it was found that the tensile strength of anisotropic-MRE was higher than that of isotropic-MRE and the hardness was reverse.