Preparation And Characterization Of Plasticity Magnetorheological Gel Based On PDMS

Plastic magnetorheological gel is a new type of magnetorheological material.The material has excellent magneto-rheological effect and excellent magnetic particle settling stability.Plastic magnetorheological gel not only enriches the types of magnetorheological materials,but also its unique structure and magnetic orientation make it an ideal material for studying the magnetorheological mechanism.In this paper,the preparation of a plastic magnetorheological gel matrix polydimethylsiloxane(PDMS)and its composite material polydimethylsiloxane/carbonyl iron powder(PDMS/CI)were studied,and its magnetorheological performance,shear stiffening performance,and magnetostrictive drive performance were discussed systematically.First,the preparation and properties of the substrate material PDMS were studied.The boric acid high temperature product was used as a crosslinker to adjust the content of boric acid to adjust the structure of the matrix PDMS.The structure of the matrix was analyzed by X-ray diffraction analysis and infrared spectrum analysis,and the shear stiffening properties were characterized.The results show that the boric acid enters the PDMS molecular chain,thus affecting the matrix structure;the matrix material has good shear hardening performance,and with the increase of boric acid in the raw material,the relative shear stiffening effect decreases and the absolute shear stiffening effect increases.PDMS/CI MR gel was prepared by dissolving-blending-evaporating.The differences of properties of samples with different crosslink content samples and different magnetic particle contents were studied.The microscopic morphology of different samples was characterized by scanning electron microscopy(SEM).The SEM images of the samples before and after the application of magnetic field show the movement of magnetic particles in the matrix.The effects of different crosslinker content and different magnetic particle content on magnetorheological properties,shear hardening properties,and magnetic actuation properties were investigated.Represented by sample of G-3/CI-3,MR effect under different frequency,strain and temperature conditions were studied.The results show: the plastic magnetorheological gel has excellent magnetorheological effects,furthermore,different crosslink content,magnetic particle content and different external stimuli conditions have significant influence on the MR properties of the samples;the addition of magnetic particles enhances the shear stiffening effect of the sample,but the shear stiffening effect is obviously decreased after the magnetic field is applied;the magneto-rheological driving properties of magnetorheological gels are affected by the synergistic effect of the strength of the matrix material and the magnetic interactions between the magnetic particles,but are dominated by the magnetic interactions between the magnetic particles,and therefore the magnetic particles content and the strength of the magnetic field increase,the magnetorheological gel enhances its drive performance.