【作者】 王维；

【导师】 官建国；

【作者基本信息】 武汉理工大学 ， 材料加工工程， 2002， 硕士

【摘要】 本论文制备了单分散和多分散的铁纳米粒子及环氧树脂-铁纳米复合粒子，用TEM、SEM、IR、DSC、FTIR等测试手段表征了它们的结构，并详细研究了粒子的结构与微波电磁参数的关系。研究结果表明： 1．以十二烷基磷酸酯为表面活性剂在液相中热分解五羰基铁制备了单分散的α-Fe纳米粒子，发现随表面活性剂用量增加纳米粒子粒径减小，粒子介电常数下降，磁导率上升；粒子介电常数和磁导率在粒径为39nm左右分别出现最小值和最大值。脱除部分包覆在纳米粒子表面的表面活性剂，可以明显降低铁纳米粒子的介电常数而对磁导率影响不大；减小纳米粒子表面的表面活性剂脂肪链链长使粒子的介电常数和磁导率均有大幅提高。 2．以双端氨基柔性大分子为表面活性剂制备了多分散的α-Fe粒子，并在此基础上以原位聚合复合法制备了环氧树脂-铁纳米复合粒子，发现随表面活性剂用量增加，复合粒子介电常数实部和磁导率先降低后增加，在表面活性剂用量为0.5g时复合粒子有较好的综合性能，频散特性优于传统微米羰基铁吸收剂。热传质问题是批量制备复合粒子的关键。 3．使复合粒子表面氧化，球磨破碎复合粒子或在制备α-Fe粒子时添加Span-80均可以降低复合粒子的介电常数，但复合粒子表面氧化同时使粒子磁导率虚部也有较大降低。 4．微米铁-纳米铁核壳复合粒子在壳层厚度为120nm时，磁导率有极大提高，表现出协同效应；在2GHz处磁导率实部、虚部均高于对应的纳米或微米粒子相应值的25％以上。更多还原

【Abstract】 Monodispersed and polydispersed iron nano particles, and epoxy resin-iron composite particles have been synthesized. The structure of the particles was characterized by TEM> SEM\ IR, DSC, FTIR etc. The relationship between the particles structure and the microwave electromagnetical parameters have been studied detailedly in this thesis. The results showed in the following:1. Monodispersed particles may be synthesized by thermal decomposing iron pentacarbonyl in liquid phase containing lauryl-phosphate mono-ester as the surfactant. With increasing dosage of the surfactant, the grain size of the particles decreases, as a result, the permittivity decreases and the permeability increases. The minimal permittivity and the maximal permeability occur at the diameter of about 39 nm. Removing partial surfactant covering on nanoparticles reduce the permittivity of particles remarkably, but little effect on the permeability; Decreasing the aliphatic chain length of the surfactant can improve both permittivity and permeability of particles evidently.2. Polydispersed a -Fe nanoparticles have been obtained by using bi-amine terminated polyurethane flexible macromolecule as a surfactant, and on the basis of them, the epoxy-iron nanocomposite particles have been synthesized by in situ polymerization compositing technology. The real parts of both the permittivity and the permeability of the nanocomposite decrease firstly and then increse with increasing dose of surfactant. The composite particles have ideal comprehensive properties at the dosage of the sufactactant of 0.5 g, and its frequency dispersion exceeds that of traditional micrometer carbonyl iron powders. Thermal mass transfer is the key to mass production.3. The surface oxidation of the composite particles, breakage of the composite particles using ball milling or the addition of Span-80 when synthesized may reduce the permittivity of the composite particles, but the surface oxidation may also reduce the imaginary part of the permeability of the composite particles.4. Synergistic effect exists when the shell thickness of the micrometer iron-nano iron core-shell structure composite particles is about 120nm, at which the permeability greatly increases. The real part and the image part of the permeability at 2 GHz obviously greater by 25% than the corresponding values of the iron microparticles and iron nanoparticles.更多还原