Preparation And Evaluation Of Magnetorheological Elastomer Modified By ZDMA

Magnetorheological elastomer(MRE)is a new type of smart composite made ofmagnetic particles dispersed in elastomers.The main characteristic of this material is that its viscoelastic properties such as its storage modulus,loss modulus and damping factor can change rapidly and reversibly with the applied magnetic field.It has wide application prospects in the fields of prosthetics,rehabilitation machines,aerospace,ships,construction bridges,vibration control,shock absorption and noise reduction.However,The magnetic particles in general magnetorheological elastomers are difficult to disperse uniformly,which is the main reason that restricts its relative magnetorheological effect and leads to poor extension performance.It is of great significance for improving the magnetorheological and mechanical properties of magnetorheological elastomers to find the additives that can improve the dispersibility of magnetic particles in the matrix.In this paper,zinc methacrylate(zinc dimethacrylate,ZDMA)was selected as a dispersant,and the magnetorheological elastomer with silicon rubber as the matrix and carbonyl iron powder as dispersed phase was prepared.The magnetorheological elastomers with 0phr,5phr,10 phr,15phr,20 phr and 25 phr ZDMA were prepared respectively.The microstructure and microstructure of the 6 groups were characterized by SEM,FTIR and cross-linking density test.The Fe element in the Mapping diagram was quantified to investigate the effect of different content of ZDMA on the dispersion of magnetic particles in the matrix.The results show that the dispersion uniformity of the magnetic particles in the magnetorheological elastomer with ZDMA is improved and the crosslink density is significantly increased.In particular,the magnetic particles in the magnetorheological elastomer are dispersed most uniformly,and the crosslink density of the magnetorheological elastomer increases most significantly when 15 phr ZDMA is added.Therefore,the addition of zinc dimethacrylate improves the dispersion uniformity of the magnetic particles to some extent.Furthermore,the tensile properties,dynamic viscoelastic properties and magnetorheological effects of 6 groups of magnetorheological elastomers with different content of ZDMA were evaluated and compared.The experimental results of tensile test showthat the fracture strength of the ZDMA magnetorheological elastomer is reduced to a certain extent,but the elongation at break is obviously improved.In particular,when 15 phr ZDMA was added,the elongation at break of the magnetorheological elastomer reached 742% from375% of the control sample(without ZDMA).The elongation at break of the ZDMA sample added was 98% higher than that of the control sample.The test results of viscoelasticity show that the storage elastic modulus and loss modulus of the magnetorheological elastomer with ZDMA are higher than that of the magnetorheological elastomer without ZDMA.And this trend is consistent under magnetic field strengths of 0mT,115 mT,234mT,456 mT,and545mT.The magnetorheological properties test results show that the relative magnetorheological effect of magnetorheological elastomers increases with the addition of ZDMA.In particular,the relative magnetorheological effect of the magnetorheological elastomer filled with 15 phr of ZDMA reached 170%,which is 43% higher than that of the sample without ZDMA.It can be seen that the addition of ZDMA improves the dispersion uniformity of the magnetic particles in the silicone rubber matrix so that the elongation at break and the magnetorheological effect of the magnetorheological elastomer are significantly improved.