| 초록 |
For industrial applications of the magnetorheological (MR) fluids of which micron sized magnetic particles are dispersed in medium oils, several problems have to be improved, since most of the magnetic particles used in MR fluids show serious sedimentation problem due to the high density as well as the abrasion of the equipment. In this work, nano-sized PMMA particles synthesized were added into the MR fluid to prevent the sedimentation of the micron-sized carbonyl iron (CI) particles. For easy process of purifying dispersant after synthesis, the PMMA nanoparticles were synthesized by soap free emulsion polymerization. The weight fraction of PMMA in suspensions was fixed to 0.1 ~ 1%. Morphology of the nano-sized PMMA particle was confirmed via scanning electron microscope (SEM) images. Stability of sedimentation of the MR fluid was observed by turbiscan optical analyzer, showing that PMMA addition improved suspension stability with less sedimentation. |
