Behavior of magnetorheological elastomers with coated particles

Abstract

Iron particle coating can improve the behavior of magnetorheological elastomers (MREs) by inhibiting iron particle rusting; however, such a process can change physical properties of MREs such as oxidation resistance, shear modulus, and stiffness change due to an applied magnetic field. In this study, MRE samples are fabricated with regular and polymerized iron particles. To investigate the possibility and extent of these changes, polymerized particle MRE samples are made using a combination of reversible addition fragmentation chain transfer and click chemistry. Shear test sample MREs with pure elastomer and 50 wt% MRE with and without polymerization are fabricated. To observe the effect of oxidation on shear properties of MREs, pure elastomer and 50 wt% coated and non-coated samples are oxidized using accelerated oxidation procedure. Experimental results show that oxidation significantly reduces the shear modulus of the elastomer matrix. The coating process of iron particles does not significantly change the shear modulus of resulting MREs but reduces the loss of shear modulus due to oxidation.

Theoretical Study of Nanocomposite Permittivity with a Tunable Clustering of Inclusions

“…This effect becomes stronger in nanocomposites because of the increased surface interaction energy between smaller inclusions separated by smaller distances. The use of surface‐functionalized fillers [ 41,96,107,117,128–131 ] to build a matrix‐free nanocomposite, or tailoring the dispersion of nanoparticles by designing the chain architecture [ 132 ] can solve this aggregation issue. Nevertheless, the scarcity of permittivity data prevents a reasonable testing of the mixing rules for such nanocomposites.…”

“…Homogeneous distributions of particles in experimental studies can be achieved by the functionalization of their surfaces. [ 41,96,107,117,128–131 ] In ref. [132], the influence of polymer chain architecture on nanoparticle dispersion and the mechanical behavior of the polymer nanocomposite are examined in coarse‐grained simulations.…”

Effect of Sonication Time on Magnetorheological Effect for Monomodal Magnetic Elastomers

“…It is well known that the dispersibility of magnetic particles strongly influences the magnetic-field response. The dispersibility of magnetic particles can be improved on a micro- or nano-scale, by the surface modification of magnetic particles [15,16,17,18], resulting in the giant magnetorheological response. For example, a magnetic elastomer with nanoscale homogeneity shows a large increase in Young’s modulus at relatively weak magnetic fields [19].…”

Magnetic Particle Filled Elastomeric Hybrid Composites and Their Magnetorheological Response

“…Recently, some studies to overcome this problem by fabricating the magnetic particles being surface-modified with organic or inorganic materials have been reported by using proper compatibilizers [ 74 , 75 , 76 , 77 , 78 , 79 ]. Li et al [ 75 ] prepared core-shell structured poly(methyl methacrylate) (PMMA)-coated CI particles to investigate the effect of particle coating on the dynamic properties of the MR elastomers with PMMA matrix.…”

“…It was found that the MR elastomers with surface-coated iron particles possessed superior mechanical properties with respect to the oxidation stability test. Behrooz et al [ 77 ] prepared poly(tetrafluoropropyl methacrylate) (PTFPMA)-coated iron particles utilizing a combination of reversible addition fragmentation chain transfer polymerization and click chemistry techniques. The PTFPMA-coated iron particles did not show a significant change in the shear modulus of the MR elastomers, but the loss of shear modulus due to oxidation was reduced.…”