核-壳结构磁性复合微球的制备与表征

通过分散共聚制得了聚(丙烯酸-丙烯腈-苯乙烯)(PAAS)三元共聚物微球,调整聚合反应介质乙醇与水的体积比及分散剂的用量,可将PAAS微球的粒径控制在230～680nm的范围内;扫描电子显微镜观察发现,所得微球粒径具有较好的单分散性.以该PAAS共聚物微球为载体,在二价和三价铁盐存在的条件下控制体系的pH,经共沉淀将Fe_3O_4纳米颗粒有效沉积在微球表面,得到了以PAAS为核,Fe_3O_4为壳的核-壳结构磁性复合微球;热重分析结果表明,复合微球上Fe_3O_4的含量达41%,对磁场具有明显的响应性.

Preparation and characterization of magnetic composite microspheres with core-shell structure

Poly (acrylic acid)-co-polyacrylonitrile-co-polystyrene (PAA-co-PAN-CO-PSt) microspheres were pre-pared by dispersion copolymerization of acrylic acid, acrylonitrile and styrene using polyvinylpyrrolidone (PVP) as stabiliz-er. The diameter of the PAA-cco-PAN-co-PSt microspheres was controlled in range of 230 to 680 nm by adjusting ratio of ethanol to water and amount of stabilizer PVP. Fe_3O_4 nanoparticles were synthesized through adjusting pH of reaction sys-tem in the presence of Fe (Ⅱ/Ⅲ) salt and deposited on surfaces of the PAA-co-PAN-co-PSt microspheres by chemical co-precipitation. The finally formed magnetic composite microspheres had a core-shell structure, which with PAA-co-PAN-co-PSt as core and Fe_3O_4 as shell. The Fe_3O_4 content of the magnetic composite microspheres was reached to 41% based on the analysis of TGA. The composite microspheres obvious had magnetic response under magnetic field.