Development and characterization of magnetorheological polymer gels

Abstract

Magnetorheological materials have been used in many applications in recent years. To develop new materials, polyurethane and silicone polymer gels were investigated. Rheology is qualitatively controlled for each system by controlling the concentration of reactants and diluents. The resulting polymers have solid, gel, or liquid states, depending on the crosslinking and dilution. The gels were characterized through kinetic analysis. Differential scanning calorimetry (DSC) was used with analysis methods to find the kinetic properties for diluted and undiluted polyurethane systems. Heat of reaction, order of reaction, preexponential constant, and activation energy were obtained from the experimental DSC data.

Synthesis and characterization of magnetorheological polyimide gels

“…The linear relation in this log-log plot indicates that the apparent viscosity is proportional to the power function of shear rate described by eq. (6). The values of ⌬ increase slightly with increasing magnetic field from 0.84 to 0.91 in the range of magnetic field investigated.…”

“…Adjusting the ratio of resin to crosslinker and percentage of diluents can control the off-state rheology of the system. 6 Mei also investigated static shear yield stress, off-state viscosity, and sedimentation properties of similar systems. 7 In this paper, MRPGs with improved redispersion performance and high temperature resistance property are investigated.…”

“…MRPGs are a new generation of materials used in vibration control and damping devices. Wilson et al 6 studied MRPGs prepared by suspending iron particles in silicone gel or polyurethane gel. Adjusting the ratio of resin to crosslinker and percentage of diluents can control the off-state rheology of the system.…”

Nanostructured and Surface Polymerized Iron Particles for Magnetorheological Fluids

“…Using the later method, a new generation of MRFs, known as magnetorheological polymer gels (MRPGs) used in vibration control and damping devices have been developed by Fuchs and coworkers. [4][5][6] These fluids contain partially crosslinked polymer gels, which are synthesized using non-stoichiometric amounts of monomers. Two MRPGs have been developed, [6] one is hydrocarbon polyol polyurethane MRPG, the other is silicone MRPG.…”

“…The latter case may result in precipitation of polymeric gel on the surface of the iron particles and improve the stability of the system. [4] However, a consideration relating to MRPG is that the interaction between polymer and iron particles' surfaces is physical absorption. Therefore the effect of inhibition of particles sedimentation and suspension stability has been limited.…”