摘要
报道了具有核壳结构的Fe3O4 聚吡咯磁性纳米微球的合成方法和表征结果 .微球同时具有导电性和磁性能 .在优化的实验条件下 ,可得到饱和磁化强度为 2 3 4emu g ,矫顽力为 45 2Oe的磁性微球 .微球的导电性随着微球中Fe3O4含量的增加而下降 .微球的磁性能则随着Fe3O4含量的增加而增大 .Fe3O4磁流体的粒径和磁性聚吡咯微球的粒径均在纳米量级 .纳米Fe3O4粒子能够提高复合物的热性能 .实验表明 ,磁流体和聚吡咯之间存在着一定的相互作用 ,正是这种相互作用使磁性聚吡咯纳米微球的热稳定性提高 .
A novel approach to synthesize core-shell nanoparticles with Fe3O4 as the magnetic core and PPY as the conducting shell was investigated. The Fe3O4 nanoparticles primarily prepared by precipitation-oxidation method, and the Fe3O4-PPY nanoparticles with core-shell structure was synthesized via an in-situ polymerization of pyrrole monomer in an aqueous solution containing well-dispersed Fe3O4 nanoparticles and surfactant NaBS. The particles are almost spherical with diameters ranging from 20 similar to 30 nm. These particles are polydisperse and some of them agglomerated due to magneto-dipole interactions between particles. 70% to 80 % of the Fe3O4-PPY particles are ranged from 30 similar to 40 nm in diameter. The core-shell structure of nanoparticles was evidenced by TEM observations. The Fe3O4 content was found to affect significantly both the conductivity and the magnetization of the resulting PPY composites. When 9 % Fe3O4 was incorporated into PPY, the conductivity of PPY composite was greatly reduced from 6.52 x 10(-3) to 1.94 x 10(-4) S/cm. Further increasing of Fe3O4 content from 8.2% to 28.2wt% resulted in slight reduction of the conductivity at room temperature. The decrease in conductivity of Fe3O4-PPy Composites with increasing Fe3O4 content was due to a decrease in the doping degree, assigned as S/N ratio. The S/N ratios decrease from 0.34 to 0.19 with increasing Fe3O4 content from 0 to 28.2%. The magnetic properties of the Fe3O4-ppy nanocomposites depend on the Fe3O4 content too. Increasing Fe3O4 content from 0 to 28.2% considerably increased both the saturated magnetization ( Ms) and the coercive force ( Hc) from 0 to 23.42 emu/g and 0 to 45.2 Oe, respectively. Since PPY powder is not magnetic, the ferromagnetic properties of the composites are attributed to the magnetic Fe3O4 nanoparticles. The magnetic Fe3O4 nanoparticles can improve the thermal stability of Fe3O4-polypyrrole nanocomposites due to interaction between Fe3O4 particles and PPY chains.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2003年第3期393-397,共5页
Acta Polymerica Sinica
基金
香港理工大学ASD基金
中国工程物理研究院预研基金 (基金号 2 0 0 2 0 86 3)资助项目
