纳米Fe_3O_4/聚苯乙烯均匀分散体系的制备及结构

Preparation and Structure of Fe_3O_4 Nanoparticle-polystyrene Uniformly Dispersed System

用化学共沉淀法制备了Fe_3O_4纳米颗粒,以油酸为表面活性剂,苯乙烯为载液,制备了稳定的纳米Fe_3O_4可聚合磁流体,将可聚合磁流体经自由基引发聚合制成纳米Fe_3O_4/聚苯乙烯均匀分散体系,用WAXRD研究了Fe_3O_4纳米粒子的结晶情况;用FTIR研究了油酸表面改性前后Fe_3O_4粒子表面官能团的变化;用TEM研究了Fe_3O_4颗粒的粒径大小及其在苯乙烯单体和聚苯乙烯中的分散情况;用DSC和TGA研究了纳米Fe_3O_4/聚苯乙烯均匀分散体系的玻璃化转变温度(T_g)和热稳定性,结果表明,合成的纳米Fe_3O_4为立方晶型,平均粒径在10nm左右,油酸分子在Fe_3O_4表面是化学吸附,经表面处理的Fe_3O_4超细颗粒在苯乙烯和聚苯乙烯基体中分散较均匀。界面粘结较好,含1.8％Fe_3O_4纳米颗粒的聚苯乙烯的最大热失重温度比聚苯乙烯提高了13 K,Fe_3O_4/聚苯乙烯复合体系的饱和磁化强度σ_s为17.43 emu/g。

The nano-particles of Fe3O4 were prepared by a chemical co-precipitation method. A stable polymerizable magnetic fluid of nano-Fe3O4 was obtained by dispersing oleic acid-coated Fe3O4 nano-particles in styrene as a carrier liquid. A uniformly dispersed system of nano-particles of Fe3O4 in polystyrene has been acquired by the free radical polymerization of polymerizable magnetic fluid. The crystallization behavior and the surface of Fe3O4 nano-particles before and after the modification by oleic acid were investigated by WXRD and FTIR, respectively. The particle size and size dispersion of Fe3O4 nano-particles in styrene and polystyrene were studied by TEM. The glass transition temperature (Tg) and the thermal stability of nano-Fe3O4 /polystyrene dispersion system were also studied by means of DSC and TGA, respectively. The results indicate that the nano-Fe3O4 is a cubic crystal, the particle size is 10 nm on an average, the oleic acid molecules are chemically adsorbed on the surface of Fe3O4 nano-particles, the modified Fe3O4 nano-particles are dispersed homogeneously in styrene and in polystyrene. The temperature at sharp weight loss of polystyrene containing only 1.8% Fe3O4 nano-particles is 13 K higher than polystyrene and its saturation magnetization is 17. 43 emu/g.