Optimization of pre-structuring parameters in fabrication of magnetorheological elastomer

Pre-structuring of magnetic particles during fabrication of magnetorheological elastomer (MRE) is a crucial step, which results in the formation of chain-like columnar structures in the rubber matrix. In this study, MRE based on natural rubber and carbonyl iron particles were prepared. The Taguchi method was utilized to study the effect of several dominating factors during the fabrication process such as pre-curing time, pre-curing temperature and applied magnetic field during curing on the loss tangent (tan δ) and tensile properties. Tan δ was measured through parallel-plate rheometer over a frequency range of 1–100 Hz and a strain amplitude range of 0.1–6%. Tensile properties were measured with a universal tensile testing machine. The obtained data were statistically analyzed using S/N ratios and ANOVA in order to predict the optimal combination of factors, and then further experiments were conducted for verification purpose. Results indicated that the magnetic field had the greatest influence on tan δ when measured over a range of frequency and elongation at break. Furthermore, pre-curing time and magnetic field were found to influence tan δ when measured over a range of strain amplitude. However, none of the factors exhibited significant influence on tensile strength. In addition, the morphology of MRE was examined using scanning electron microscopy (SEM).