Magneto-mechanical properties of elastic hybrid composites (original) (raw)
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Journal of Magnetism and Magnetic Materials, 2012
Viscoelastic and deformational behavior of soft magnetic elastomers with hard magnetic fillers under the influence of a magnetic field is studied by different experimental techniques. The magnetic elastomers used in this work were synthesized on the basis of silicone rubber filled with FeNdB particles and were magnetized in a field of 3 and 15 kOe. We have shown that due to high residual magnetization the materials demonstrate well pronounced non-elastic behavior already in the absence of any external magnetic field. In particular, in contrast to magnetic elastomers based on soft magnetic fillers their elastic modulus is strain-dependent. Under the influence of external magnetic field the storage and loss moduli of magnetic elastomers with hard magnetic filler can both increase and decrease tremendously.
Polymers for Advanced Technologies, 2020
Funding information Natural Sciences and Engineering Research Council of Canada; Fonds de recherche du Québec-Nature et technologies Polydimethylsiloxane (PDMS)/iron oxide magnetic nanoparticle (NP) composites with tailored mechanical properties are prepared for use in magnetically actuated soft devices based on their controlled deformation by the application of an external magnetic field. This investigation reports the synthesis and functionalization of iron oxide NPs, the preparation of the PDMS/NP composites, the evaluation of NP dispersion using scanning electron microscopy (SEM) and optical microscopy, and the mechanical characterization of the composite films. Characterization includes rheological measurements as well as stress-strain curves to obtain the Young modulus and elongation at break. SEM is used to probe individual NP dispersion, whereas optical microscopy provides rapid access to quantitative information about the size and distribution of particle aggregates. Results for nonfunctionalized (nf), oleic acid (OA)coated, and stearic acid (SA)-coated iron oxide NPs and their blends are presented. PDMS elastomers containing both OA-and SA-coated iron oxide NPs are found to have very low Young moduli with substantially higher resistance to failure than neat PDMS. For example, a formulation containing 2.5 wt% OA-coated NPs and 2.5 wt% SA-coated iron oxide NPs has a modulus of 0.15 MPa (compared with 0.24 MPa for neat PDMS), while it can withstand an elongation of about 1.5 times its initial length compared with only 0.3 times for neat PDMS. As a comparison, the modulus of the most commonly used commercial PDMS elastomer (Sylgard 184) is an order of magnitude higher than that of the composites prepared here, whereas maximum elongation is similar for the two. The formulations developed in this work could be used in applications where high deformability is required with limited magnetic field strength and/or NP loading.
Multifunctional magnetic soft composites: a review
Multifunctional Materials
Magnetically responsive soft materials are soft composites where magnetic fillers are embedded into soft polymeric matrices. These active materials have attracted extensive research and industrial interest due to their ability to realize fast and programmable shape changes through remote and untethered control under the application of magnetic fields. They would have many high-impact potential applications in soft robotics/devices, metamaterials, and biomedical devices. With a broad range of functional magnetic fillers, polymeric matrices, and advanced fabrication techniques, the material properties can be programmed for integrated functions, including programmable shape morphing, dynamic shape deformation-based locomotion, object manipulation and assembly, remote heat generation, as well as reconfigurable electronics. In this review, an overview of state-of-the-art developments and future perspectives in the multifunctional magnetically responsive soft materials is presented.
Polymers
The demand for multi-functional elastomers is increasing, as they offer a range of desirable properties such as reinforcement, mechanical stretchability, magnetic sensitivity, strain sensing, and energy harvesting capabilities. The excellent durability of these composites is the key factor behind their promising multi-functionality. In this study, various composites based on multi-wall carbon nanotubes (MWCNT), clay minerals (MT-Clay), electrolyte iron particles (EIP), and their hybrids were used to fabricate these devices using silicone rubber as the elastomeric matrix. The mechanical performance of these composites was evaluated, with their compressive moduli, which was found to be 1.73 MPa for the control sample, 3.9 MPa for MWCNT composites at 3 per hundred parts of rubber (phr), 2.2 MPa for MT-Clay composites (8 phr), 3.2 MPa for EIP composites (80 phr), and 4.1 MPa for hybrid composites (80 phr). After evaluating the mechanical performance, the composites were assessed for ind...
Magnetoactive elastomer composites
Polymer Testing, 2004
This paper deals with the development of magnetoactive elastomers and the exploration of some of their potential applications. In the course of material development, samples of particle-filled silicone rubber were produced and their mechanical and magnetic properties were experimentally determined. The test specimens consisted of pure and filled silicone with randomly dispersed as well as aligned magnetizable particle chains. To align the embedded particles in the elastomer, cross-linking of the resin took place in a magnetic field. Composite elastomer samples with different types of micron-size particles and various volume fractions were tested. Through alignment of the embedded particles, relative to pure silicone, the tensile strength increased by 80%, the tensile modulus by 200%, and the compression modulus by more than 300%. The maximum tensile strain of filled samples was generally reduced; however, samples with longitudinally aligned particles retained a relatively high strain capability as in the pure silicone rubber. Furthermore, to determine the active response of the composite, magnetic tests and coupled mechanical-magnetic experiments were performed. The magnetoactive elastomer composites produced and tested in this work demonstrated certain actuator force properties. The equivalent magnetic force calculated on the basis of these experiments and the magnetosolid mechanics theory showed the dependence of the magnetic force on the distribution of the particles in the elastomer. The elasto-magnetic behavior of beam samples was investigated by exposing the filled elastomer to the action of a permanent magnet at various gap distances, which led to the determination of a so-called magnetic bending stiffness. Moreover, through these experiments the influence of the particle alignment on the critical gap distance of the elastomagnetic instability of composite elastomer was quantitatively estimated. The compression tests on cylindrical samples in the absence and the presence of a magnetic field showed that the magnetic field would increase the stiffness of the material. These experiments lead to useful hints regarding the use of such elastomer composites as tunable force structural elements.
2020
New silicone magnetoactive elastomers have been investigated. Changes in elastic properties and resonance frequencies shifts in the investigated composite materials samples at the imposition external constant magnetic fields have been fixed by dynamic testing methods on vibration test benches. The method is developed and a calculation example necessary deformation creation in a magnetoactive material by means of electromagnetic fields influence is shown. The given technique of using the influence on the polymer elastic material by the electromagnetic field creates the possibility, by means of the given program specifications, to support the necessary decision on changing the dynamic characteristics (in accordance with the task changing factors in view). The material under development has a direct relation to robotics sensation, to creation of materials which are also called "smart materials". The studies show their possible application as intelligent sensors or sensors with magnetic field force feedback, which transmit signals to the computer's software control unit to support optimal decisions for "soft robotics" specified by the technical conditions. The material can be adapted as a touch sensor, allowing robots to feel the change in elastic properties in the object being contacted. The results show that it is possible to create structures for use in robotic devices based on electrically and magnetically controlled elastic polymer materials, providing a number of advantages over those currently in use.
Stress induced by the striction of hybrid magnetoactive elastic composites
Journal of Magnetism and Magnetic Materials, 2019
In this study we experimentally examine the mechanical stress induced by the striction of hybrid magnetoactive elastic composites in the direction parallel to an externally applied magnetic field. Elastic samples based on a polydimethylsiloxane matrix with embedded spherical magnetic soft carbonyl iron particles, spherical magnetic hard NdFeB-alloy particles as well as on a mixture of the two kinds of powder are under investigations. An effect of the structuring and pre-magnetization of the samples on the stress induced by the magnetodeformational effect is evaluated.
Physical Sciences Reviews, 2020
Hybrid magnetic elastomers (HMEs) belong to a novel type of magnetocontrollable elastic materials capable of demonstrating extensive variations of their parameters under the influence of magnetic fields. Like all cognate materials, HMEs are based on deformable polymer filled with a mixed or modified powder. The complex of properties possessed by the composite is a reflection of interactions occurring between the polymer matrix and the particles also participating in interactions among themselves. For example, introduction of magnetically hard components into the formula results in the origination of a number of significantly different behavioral features entirely unknown to magnetorheological composites of the classic type. Optical observation of samples based on magnetically hard filler gave the opportunity to establish that initial magnetization imparts magnetic moments to initially unmagnetized grains, as a result of which chain-like structures continue to be a feature of the mat...
Smart Magnetic Composites (SMC)
Metal, Ceramic and Polymeric Composites for Various Uses, 2011
Composite Materials elastomers filled with ferromagnetic material powders (e.g. carbonyl iron, GMM or their combination), polymers on the epoxy resin base containing powdered ferromagnetic materials,-solid magnetocaloric materials. Below, the following Smart Magnetic Composites have been discussed in detail: • Composites of porous matrix filled with magnetorheological fluid (MagnetoRheological Composites-MRC), • MagnetoRheological Elastomers-MRE, known also as Magneto-Active Elastomers-MAE), • Composites containing powdered material of giant magnetostriction (Giant Magnetostrictive Materials composites-GMMc). In each of the above cases the manufacturing technologies, ways of stimulating with magnetic field, methodology of research and properties identification as well as application examples, have been discussed. The material has been enriched with literature overview and results of the Authors' own research.
Magnetic Hybrid-Materials, 2021
Hybrid magnetic elastomers (HMEs) belong to a novel type of magnetocontrollable elastic materials capable of demonstrating extensive variations of their parameters under the influence of magnetic fields. Like all cognate materials, HMEs are based on deformable polymer filled with a mixed or modified powder. The complex of properties possessed by the composite is a reflection of interactions occurring between the polymer matrix and the particles also participating in interactions among themselves. For example, introduction of magnetically hard components into the formula results in the origination of a number of significantly different behavioral features entirely unknown to magnetorheological composites of the classic type. Optical observation of samples based on magnetically hard filler gave the opportunity to establish that initial magnetization imparts magnetic moments to initially unmagnetized grains, as a result of which chain-like structures continue to be a feature of the material even after external field removal. In addition, applying a reverse field causes them to turn into the polymer as they rearrange into new ring-like structures. Exploration of the relationship between the rheological properties and magnetic field conducted on a rheometer using vibrational mechanical analysis showed an increase of the relative elastic modulus by more than two orders of magnitude or by 3.8 MPa, whereas the loss factor exhibited steady growth with the field up to a value of 0.7 being significantly higher than that demonstrated by elastomers with no magnetically hard particles. At the same time, measuring the electroconductivity of elastomers filled with a nickel-electroplated carbonyl iron powder made it possible to observe that such composites demonstrated an increase of variation of the resistivity of the composite influenced by magnetic field in comparison to elastomers containing untreated iron particles. The studies conducted indicate that this material exhibits both magnetorheological and