Enhancing Effect of Fe₃O₄/Nanolignocelluloses in Magnetorheological Fluid

Magnetorheological fluid (MRF) is an intelligent material, which can be controlled by an external magnetic field. It is widely used in damping, finishing, mechanical transmission, sealing, and other engineering fields due to its magnetorheological (MR) effect. However, despite decades of research and experimental development, the wide application of MRF is still restricted by its serious settlement problem owing to the density difference between the magnetic particles and carrier liquid. Here, using the coprecipitation method, a kind of Fe₃O₄-modified nanolignocellulose (Fe₃O₄/NLC) composite fiber was characterized by its unique advantages such as low density, soft magnetism property, and high specific surface. These Fe₃O₄/NLCs were used as a kind of reinforcing particle with carbonyl iron powder in the new bidisperse MRF system. The performances of MRF samples were enhanced by these superior properties. We found that all MRF samples with composite fibers exhibited excellent antisettlement and dynamic mechanical characteristics and cooperativity between Fe₃O₄ and NLCs. Furthermore, redispersibility of MRF is qualitatively evaluated by a shearing test in this paper, explaining the high property of antihardening. This composite fiber improves the comprehensive performance of MRF and has the potential to be repeatedly used in engineering applications.