溶剂蒸发法制备磁性微胶囊及其相关性能

Preparation of Magnetic Microcapsules by Solvent Evaporation Method and Corresponding Properties

摘要:

将共沉淀法所得纳米OA-Fe3O4（亲油改性Fe3O4）分散于不同介质中形成磁流体作为芯材，以PMMA（聚甲基丙烯酸甲酯）作为壁材，采用溶剂蒸发法制备磁性微胶囊。对不同芯材及乳化剂进行筛选；考察乳化剂用量、m(芯材):m(壁材)及乳化转速对微胶囊制备的影响。通过XRD，FTIR，TEM，SEM，光学显微镜，VSM（振动样品磁强计）对纳米OA-Fe3O4和磁性微胶囊的有效成分、形貌、热性能、磁性能进行分析表征。结果表明：共沉淀法制备的纳米颗粒有效成分为Fe3O4且可形成稳定磁流体。OA-Fe3O4粒径在3~15nm，比饱和磁化强度为43.3emu/g，具有顺磁性。以分散在n-C16H34的OA-Fe3O4磁流体为芯材，在SDS（十二烷基硫酸钠）占乳化总量质量分数2%，m(芯材):m(壁材) =5:1，乳化转速800r/min条件下可制得外形规整，壁厚1~2μm且粒径集中于10±2μm的磁性微胶囊。该胶囊比饱和磁化强度为36.9emu/g，具有良好的磁响应性。

Abstract:

In this paper, the magnetic microcapsules were prepared by means of solvent evaporation. Core material was magnetofluid whose nano OA-Fe3O4 (oleic acid modified Fe3O4) magnetic particles prepared with coprecipitation were dispersed in different solvent media. Shell material was PMMA (polymethyl methacrylate). Optimum core material and emulsifier were selected. The encapsulation parameters, including mass fraction of emulsifier, core material to shell material mass ratio and shearing emulsification rate were investigated respectively. The active ingredient, morphology, thermal property and magnetic responsiveness of OA-Fe3O4 and magnetic microcapsule were characterized by XRD, FTIR, TEM, SEM, optical microscope and VSM (vibrating sample magnetometer). The results show that the effective ingredient of nanoparticle prepared by coprecipitation is Fe3O4, which can be successfully microencapsulated. The OA-Fe3O4 exhibits monodispersity, and its particle size is 3-15nm. OA-Fe3O4 also shows superparamagnetism, and its saturation magnetization is 43.3emu/g. The optimum process parameters of preparing magnetic microcapsules as follows: Magnetofluid of OA-Fe3O4 dispersing in n-C16H34 is core material, mass fraction of emulsifier SDS (sodium dodecyl sulfonate) to total emulsion is 2%, core material to wall material mass ratio is 5:1, and shearing rate is 800r/min. The wall thickness of magnetic microcapsule is 1-2μm and the particle size is concentrated on 10±2μm. The saturation magnetization of magnetic microcapsule is 43.3emu/g, which shows good magnetism response under magnetic field.