Chain formation mechanism of magnetic particles in magnetorheological elastomers during pre-structure

2021 ◽  
Vol 527 ◽  
pp. 167693
Author(s):  
Heng Wu ◽  
Zhiqiang Xu ◽  
Jun Wang ◽  
Xinqian Bo ◽  
Zhifa Tang ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Magnetic Particles ◽  
Chain Formation ◽  
Magnetorheological Elastomers

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

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7026
Author(s):  
Norizatie Muhammad Zaki ◽  
Nurul Azhani Yunus ◽  
Muhamad Shakir Yusoff ◽  
Saiful Amri Mazlan ◽  
Siti Aishah Abdul Aziz ◽  
...  
Keyword(s):  
Magnetic Particles ◽  
Physicochemical Characteristics ◽  
Magnetorheological Elastomers ◽  
Weight Percentage ◽  
Chemical Structures ◽  
Microstructure Observation ◽  
Curing Characteristics ◽  
Similar Chemical ◽  
Low Performance ◽  
Light Mineral

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.

MONITORING INTERPARTICLE DISTANCE IN MAGNETORHEOLOGICAL COMPOSITES

2007 ◽  
Vol 21 (28n29) ◽  
pp. 4868-4874
Author(s):  
G. BOSSIS ◽  
E. COQUELLE ◽  
C. NOEL ◽  
F. GIULIERI ◽  
A. M. CHAZE
Keyword(s):  
Magnetic Field ◽  
Liquid Crystal ◽  
Energy Dissipation ◽  
Viscoelastic Properties ◽  
Magnetic Particles ◽  
Interparticle Distance ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Elastomers ◽  
Magnetic Spheres ◽  
The Creation

We describe two different systems, the first one based on a magnetorheological elastomer and the second one on magnetic particles inside a liquid crystal. In both system we manage to have chain structures with particles that are not in contact. The effect of the gap between particles on the viscoelastic properties are studied. We show in particular how in magnetorheological elastomers, the energy dissipation is closely related to the creation and the motion of cavities in the gap between the particles. In liquid crystal chaining of particles can occur without applying a magnetic field. This happens if the anchoring of liquid crystal on the surface of the particles is homeotropic. We demonstrate how the combination of elastic defects and of a magnetic field allow to obtain microscopic springs made of a pair of magnetic spheres.

Sensing Behavior of Magnetorheological Elastomers

2009 ◽  
Vol 131 (9) ◽  
Author(s):  
Xiaojie Wang ◽  
Faramarz Gordaninejad ◽  
Mert Calgar ◽  
Yanming Liu ◽  
Joko Sutrisno ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electrical Properties ◽  
Magnetic Particles ◽  
External Stimulus ◽  
Magnetorheological Elastomer ◽  
Polymer Medium ◽  
Mechanical Loads ◽  
Magnetorheological Elastomers ◽  
Impedance Response ◽  
Ferromagnetic Particles

A magnetorheological elastomer (MRE) is comprised of ferromagnetic particles aligned in a polymer medium by exposure to a magnetic field. The structures of the magnetic particles within elastomers are very sensitive to the external stimulus of either mechanical force or magnetic field, which result in multiresponse behaviors in a MRE. In this study, the sensing properties of MREs are investigated through experimentally characterizing the electrical properties of MRE materials and their interfaces with external stimulus (magnetic field or stress/strain). A phenomenological model is proposed to understand the impedance response of MREs under mechanical loads and magnetic fields. Results show that MRE samples exhibit significant changes in measured values of impedance and resistance in response to compressive deformation, as well as the applied magnetic field.

Folding Actuation and Locomotion of Novel Magneto-Active Elastomer (MAE) Composites

2013 ◽  
Author(s):  
Paris von Lockette ◽  
Robert Sheridan
Keyword(s):  
Magnetic Field ◽  
Barium Ferrite ◽  
Magnetic Particles ◽  
Flat Surface ◽  
Iron Particles ◽  
Soft Magnetic ◽  
Magnetorheological Elastomers ◽  
Vibration Attenuation ◽  
Magnetically Aligned ◽  
Mechanical Actuation

Magneto-active elastomers (also called magnetorheological elastomers) are most often used in vibration attenuation application due to their ability to increase in shear modulus under a magnetic field. These shear-stiffening materials are generally comprised of soft-magnetic iron particles embedded in a rubbery elastomer matrix. More recently researchers have begun fabricating MAEs using hard-magnetic particles such as barium ferrite. Under the influence of uniform magnetic fields these hard-magnetic MAEs have shown large deformation bending behaviors resulting from magnetic torques acting on the distributed particles and consequently highlight their ability for use as remotely powered actuators. Using the magnetic-torque-driven hard-magnetic MAE materials and an unfilled silicone elastomer, this work develops novel composite geometries for actuation and locomotion. MAE materials are fabricated using 30% v/v 325 mesh barium ferrite particles in Dow Corning HS II silicone elastomers. MAE materials are cured in a 2T magnetic field to create magnetically aligned (anisotropic) materials as confirmed by vibrating sample magnetometry (VSM). Gelest optical encapsulant is used as the uniflled elastomer material. Mechanical actuation tests of cantilevers in bending and of accordion folding structures highlight the ability of the material to perform work in moderate, uniform fields of μ0H = 150 mT. Computational simulations are developed for comparison. Folding structures are also investigated as a means to produce untethered locomotion across a flat surface when subjected to an alternating field similar to scratch drive actuators; geometries investigated show promising results.

Effects of corrosion rate of the magnetic particles on the field-dependent material characteristics of silicone based magnetorheological elastomers

2020 ◽  
Vol 29 (8) ◽  
pp. 087003 ◽  
Author(s):  
Nurul Liyana Burhannuddin ◽  
Nur Azmah Nordin ◽  
Saiful Amri Mazlan ◽  
Siti Aishah Abdul Aziz ◽  
Seung-Bok Choi ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Magnetic Particles ◽  
Magnetorheological Elastomers ◽  
Material Characteristics ◽  
Field Dependent

scholarly journals Reinforcing Behaviors of Sulfur-Containing Silane Coupling Agent in Natural Rubber-Based Magnetorheological Elastomers with Various Vulcanization Systems

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5163
Author(s):  
Mengxin Wang ◽  
Xiaoqian Hao ◽  
Wenju Wang
Keyword(s):  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Magnetic Particles ◽  
Surface Hydrophobicity ◽  
Zero Magnetic Field ◽  
Rubber Matrix ◽  
Silane Coupling Agents ◽  
Magnetorheological Elastomers ◽  
Inorganic Particles ◽  
Silane Coupling

Magnetorheological elastomers (MRE) is known as an intelligent material constituted of a rubber matrix as well as soft magnetic particles. Silane coupling agents are used to raise the interplay between the inorganic particles and rubber matrix. Silane coupling agent, bis-[-3-(trimethylsilyl propyl)tetra sulfide] (Si69), was picked for comparison of its reinforcing efficiency in the MRE with various vulcanization systems: a conventional (CV), semi-efficient (semi-EV), and efficient (EV) vulcanization system. The outcome illustrated that not only was there improved Si69 surface hydrophobicity of the magnetic particles, but also enhanced Si69 in the interplay between the rubber matrix and magnetic particles. On one hand, the saturated induced magnetic modulus and zero magnetic field modulus of MRE was increased in the vulcanization system, and the loss factor was reduced after the magnetic particles were modified by Si69. On the other hand, the effect of Si69 on the MRE depended on the vulcanization system. The Si69 provided better enhancements in the EV system due to effects of the sulfur contribution of Si69.

The formation mechanism of the initial C–C chain in ethanol synthesis on γ-AlOOH(100)

2017 ◽  
Vol 19 (29) ◽  
pp. 19300-19307 ◽  
Author(s):  
Lin Zhang ◽  
Bing Bai ◽  
Hui Bai ◽  
Wei Huang ◽  
Zhi-Hua Gao ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
High Reactivity ◽  
Chain Formation ◽  
Ethanol Synthesis

The γ-AlOOH(100) surface shows high reactivity for the initial C–C chain formation in ethanol synthesis.

Characterization of actuation properties of magnetorheological elastomers with embedded hard magnetic particles

2012 ◽  
Vol 23 (9) ◽  
pp. 1049-1054 ◽  
Author(s):  
Jeong-Hoi Koo ◽  
Alexander Dawson ◽  
Hyung-Jo Jung
Keyword(s):  
Magnetic Materials ◽  
Magnetic Particles ◽  
Iron Particles ◽  
Magnetorheological Elastomer ◽  
Hard Magnetic Materials ◽  
Magnetorheological Elastomers ◽  
Cantilevered Beam ◽  
Magnetic Poles ◽  
New Generation

This study investigates a new generation of magnetorheological elastomers based on hard magnetic particles. Unlike traditional magnetorheological elastomers that use iron particles, a dispersion of hard magnetic materials aligned in an electromagnetic field will produce a magnetorheological elastomer with magnetic poles. When a magnetic field is applied, perpendicularly to these poles, the filler particles generate torque and cause rotational motion of the magnetorheological elastomer blend. The primary goal of this study is to fabricate and characterize the actuation properties of magnetorheological elastomers filled with various hard magnetic particles. To this end, samples of magnetorheological elastomers consisting of hard magnetic materials were fabricated using four different particle types, and a test setup (electromagnet) was constructed. After mounting the magnetically anisotropic samples in a fixed-free configuration, uniform magnetic fields are applied to the samples (perpendicular to the poled direction), which causes the sample to bend, similar to a cantilevered beam. The blocked force and tip displacement of the samples were measured to characterize actuation properties of the samples. The results show that the responses of the deflection and the blocked force at the tip show linear trends over a reasonable range, suggesting that magnetorheological elastomers consisting of hard magnetic materials can be used as bending-type actuators in small mechanical systems and devices.

The study of enhancement of magnetorheological effect based on natural rubber/thermoplastic elastomer SEBS hybrid matrix

2019 ◽  
Vol 31 (3) ◽  
pp. 339-348 ◽  
Author(s):  
Xincheng Song ◽  
Wenju Wang ◽  
Fufeng Yang ◽  
Guoping Wang ◽  
Xiaoting Rui
Keyword(s):  
Natural Rubber ◽  
Smart Materials ◽  
Carbonyl Iron ◽  
Magnetic Particles ◽  
Thermoplastic Elastomer ◽  
Iron Particles ◽  
Magnetorheological Elastomers ◽  
Hybrid Matrix ◽  
The Matrix ◽  
Magnetorheological Effect

Magnetorheological elastomers are one kind of smart materials which consist of matrix materials and magnetic particles. The mechanical properties of magnetorheological elastomers were controllable under an external magnetic field. Applications of magnetorheological elastomers are limited as a result of their poor magnetorheological effect and mechanical performance, so enhancing the magnetorheological effect of them is critical for their application. Styrene-ethylene-butylene-styrene based thermoplastic elastomer was added to natural rubber to fabricate hybrid matrix–based magnetorheological elastomers. Zero modulus of magnetorheological elastomers increased from 0.50 to 0.64 MPa and magnetorheological effect increased from 28.00% to 43.75% with the addition of styrene-ethylene-butylene-styrene based thermoplastic elastomer. The contact angle of carbonyl iron particles with the matrix showed that styrene-ethylene-butylene-styrene based thermoplastic elastomer can improve the compatibility of carbonyl iron particles with the matrix. Fourier-transform infrared spectroscopy analysis has been carried out to investigate the internal structure of hybrid matrix–based magnetorheological elastomers.

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