Fe3O4-MWCNTs在环氧树脂中的定向排列

用共沉淀法制备了具有超顺磁性Fe₃O₄-MWCNTs（多壁碳纳米管）复合粒子，加入环氧树脂（EP）中，在0.6 T的弱定磁场下固化成型。采用TEM研究其定向程度及分散性，并进行动态热机械分析、差热分析和导热率测试。结果表明，MWCNTs表面包覆了磁性Fe₃O₄纳米粒子，Fe₃O₄-MWCNTs复合物按照首尾衔接的方式沿着磁场方向定向排列。Fe₃O₄-MWCNTs/EP纳米复合材料表现出明显的各向异性，垂直于Fe₃O₄-MWCNTs轴向导热率低于平行方向的导热率，Fe₃O₄-MWCNTs的加入对于平行方向的导热率影响不大。Fe₃O₄-MWCNTs的加入使环氧树脂的储能模量变小，损耗模量变大，损耗因子均大于纯环氧树脂，表现出良好的阻尼性能。当Fe₃O₄-MWCNTs与EP质量比为0.3%时，损耗因子在20 ℃的温域内大于0.7，最高值达到1.16。

Alignment of Fe3O4-MWCNTs in epoxy resin

Nanoparticles Fe₃O₄ were synthesized with co-precipitation method and coated on the surface of multi-walled carbon nanotubes (MWCNTs) to prepare the magnetic Fe₃O₄-MWCNTs hybrid. The magnetic Fe₃O₄-MWCNTs hybrid was aligned in the epoxy resin under weak magnetic field (0.6 T). Alignment and dispersion of Fe₃O₄-MWCNTs were studied by transmission electron microscope (TEM). Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermal conductivity were tested. As a result, nanoparticles Fe₃O₄ are coated on the surface of MWCNTs, hybrids are aligned end-to-up under 0.6 T magnetic field. Thermal conductivity is anisotropy, with lower thermal conductivity in vertical direction, while Fe₃O₄-MWCNTs hybrid has little effect on the parallel thermal conductivity. With adding Fe₃O₄-MWCNTs hybrid into epoxy resin, storage modulus decreases and loss modulus increases. In the meantime, loss factors of nano Fe₃O₄-MWCNTs/epoxy composites are higher than those of the pure epoxy resin exihibiting good damping property. When the mass ratio of Fe₃O₄-MWCNTs hybrid to epxy resin is 0.3%, loss factor is more than 0.7 and up to 1.16 at about 20 ℃.