Fe3O4/聚苯乙烯中空微球磁性复合微粒的制备及其磁流变性能的研究

Preparation and magnetorheological properties of magnetic composite particles based on Fe3O4/polystyrene hollow microspheres

用共沉淀法在聚苯乙烯（PS）中空微球表面包覆Fe3O4，制备了Fe3O4/Ps中空微球磁性复合微粒，当磁性包覆层的厚度为30～50nm时，复合微粒的室温表现密度为1．5g/cm^3，为传统磁流变液（MRF）中所用铁粉等软磁性颗粒密度（约7．9g/cm^3）的1/5，更为接近MRF中载液的密度。复合颗粒的磁滞回线比较狭长，呈软磁性，其磁性能和Fe3O4纳米颗粒相差不大。与Fe3O4颗粒相比，Fe3O4/PS中空磁性复合微粒在水载液中的沉降稳定性大大提高，复合微粒含量越高，其沉降稳定性越好。在磁性微粒含量相同的条件下，基于Fe3O4/PS中空磁性复合微粒的MRF的磁流变性能明显优于基于Fe3O4纳米微粒的MRF。

The soft magnetic composite particles based on Fe3O4/polystyrene hollow microspheres were prepared. The apparent density of the hollow magnetizable particles was about 1.5 g/ml, which was only one-fifth or one-fourth of that of normal magnetic particles based on Fe3O4 or Fe powder. The saturation magnetization of the magnetic composite particles is 0.21T, and the coercive force （Hc） of the magnetic composite particles was 8.03kA/m. The magnetorheological fluids based on such kind of soft magnetic composite particles show promoted sedimentation stability and magnetorheological properties, which are attributed to the novel hollow structures.